Science.gov

Sample records for osilae rodentia cricetidae

  1. [Molecular characterization of Sigmodon hirsutus (Rodentia: Cricetidae) populations in Venezuela].

    PubMed

    Lessmann, Janeth; Arrivillaga, Jazzmín; Aguilera, Marisol

    2011-06-01

    Recent phylogenetic studies based on cytochrome b gene sequence, have determined that the species historically known as Sigmodon hispidus (Rodentia) from South America comprises a species S. hirsutus of paraphyletic origin. The aim of this study was to test the hypothesis that populations from Venezuela, represent the sensu strict form, ancestral haplotypes, and monophyletic subspecieS. For this, 12 individual sequences from three localities of different biogeographic regions in Venezuela were evaluated and sequenced based on cyto b. Additionally, the sequences were used to develop a cladistic analysis and genetic distance calculations, and to compare this information with two individual sequences of Sigmodon specimens available in Genbank. Phylogenetic analyses show that the three populations of S. hirsutus of Venezuela form an ancestral and monophyletic subclade supported by high bootstrap values and significant genetic distance between subclade within the S. hirsutus. Besides, the existence of two lineages suggests two subspecies, S. hirsutus hirsutus from Venezuela, and S. hirsutus mexicanus from Mexico-Central America, but, both species need formal description.

  2. New species and records of the mite genus Prolistrophorus (Acariformes: Listrophoridae) from rodents of the subfamily Sigmodontinae (Rodentia: Cricetidae).

    PubMed

    Bochkov, Andre V; Lareschi, Marcela; Barreto, Mauricio

    2014-10-01

    Six fur-mite species of the genus Prolistrophorus Fain, 1970 (Acariformes: Listrophoridae) were recorded from Central and South American rodents of the subfamily Sigmodontinae (Rodentia: Cricetidae). Among them, Prolistrophorus (Aprolistrophorus) parabidentatus sp. nov. from Akodon azarae from Argentina and Prolistrophorus (Aprolistrophorus) tylomys sp. nov. from Tylomys nudicaudus from Guatemala are described as new for science. New hosts are recorded for the following species: Prolistrophorus (Prolistrophorus) grassii (Radford, 1954) from Zygodontomys brevicauda from Colombia, P. (P.) frontalis (Hirst, 1921) from Oligoryzomys sp. from Argentina, P. (P.) argentinus (Hirst, 1921) from Melanomys caliginosus, Akodon affinis from Colombia and Scapteromys aquaticus from Argentina, Prolistrophorus (Beprolistrophorus) hirstianus Fain, 1973 from Scapteromys aquaticus from Argentina.

  3. The tubular compartment and the spermatogenic dynamics of the wild rodent Oxymycterus nasutus (Rodentia: Cricetidae).

    PubMed

    Morais, Ana Carolina Torre; Balarini, Maytê Koch; Lopes, Elizabeth Oliveira; Menezes, Tatiana Prata; Quintela, Fernando Marques; Morais, Danielle Barbosa; Gomes, Marcos de Lucca M; Matta, Sérgio Luis P da

    2014-10-01

    Despite the order Rodentia present worldwide distribution and large number of species in the Brazilian fauna, detailed studies on testicular morphophysiology are still scarce. Therefore, this study aimed to analyze the dynamics of the spermatogenic process of Oxymycterus nasutus using morphometrical and stereological tools. Testicles from ten sexually mature males were used, showing a gonadosomatic index of 0.89%. The testicular parenchyma showed one of the highest tubulesomatic indexes reported among wild rodents - 0.82% - from which 65.12% was allocated into seminiferous epithelium. The average tubular diameter was 249.89 μm, whereas the epithelium height was 62.47 μm and the total length was 18.62 m per gram of testis. Eight different stages of the seminiferous epithelium cycle were described. Stage 1 was used for counting the germ cell population as well as the Sertoli cells. On average, 3.47 type-A spermatogonia, 24.39 primary spermatocytes in preleptotene/leptotene, 24.13 primary spermatocytes in pachytene, 68.38 round spermatids and 7.33 Sertoli cells were found per tubular cross section. There were 91.02 × 10(6) Sertoli cells per gram of testis and each cell was able to support 9.33 spermatids and 16.43 germ cells. The coefficient of spermatogonial mitosis was 7.02, while 2.83 spermatids were produced for each primary spermatocyte in pachytene. The overall efficiency of spermatogenesis was 19.70 cells, whereas the sperm reserve per gram of testis totalized 849.63 × 10(6) spermatids. Therefore, the presented data showed that O. nasutus shows a high energetic investment in reproduction, corroborating the findings for other species of the Cricetidae family.

  4. Histological and serological evidence of experimental paracoccidioidomycosis in Calomys callosus (Rodentia: Cricetidae)

    PubMed Central

    Berbert, Alceu LCV; Faria, Gabriele G; Gennari-Cardoso, Margareth L; Silva, Maria MMD; Mineo, José R; Loyola, Adriano M

    2007-01-01

    The responses of animal experimental models related to the infectivity, virulence and pathogenicity of Paracoccidioides brasiliensis is constantly used to develop new perspectives of investigation. The rodent Calomys callosus, Rengger 1830 (Rodentia: Cricetidae) is an indigenous inhabitant of the savannah environment found in the central regions of Brazil. The aim of the present work was to evaluate the histopathological and serological features of C. callosus after inoculation with the Pb18 strain of P. brasiliensis. Furthermore, A/Sn and B10.A mice strains were also tested to compare the results obtained in C. callosus to these well-established experimental models of resistance and susceptibility respectively. In every instance, survival analysis was performed, and histopathological study of the lungs, liver and spleen was employed to investigate tissue involvement, degree of inflammation and fungal presence. Levels of antibodies to P. brasiliensis were measured by using an enzyme-linked immunosorbent assay after 4 weeks and at the advanced stage of infection. The mortality rate was proportional to inoculation dose in all groups, but overall it was much superior in C. callosus than in the B10.A-susceptible mice. Macroscopical and microscopical pathological alterations were also more extensive and remarkable for C. callosus, once again proportional to inoculation dose, but more noticeable differences among the studied groups were found with 0.6 × 105 inoculum. In addition, the serological profile of C. callosus was similar to that found for B10.A-susceptible mice. Infection of C. callosus with 0.6 × 108 Pb18 inoculum resulted in more serious illness, and it decreased in severity in proportion to the inoculum dose. This difference was more pronounced in C. callosus, and the clinical, serological and pathological findings in this animal were more intense and precocious compared with the B10.A-susceptible mice. The present results suggest that C. callosus is a

  5. Histological and serological evidence of experimental paracoccidioidomycosis in Calomys callosus (Rodentia: Cricetidae).

    PubMed

    Berbert, Alceu L C V; Faria, Gabriele G; Gennari-Cardoso, Margareth L; Silva, Maria M M D; Mineo, José R; Loyola, Adriano M

    2007-02-01

    The responses of animal experimental models related to the infectivity, virulence and pathogenicity of Paracoccidioides brasiliensis is constantly used to develop new perspectives of investigation. The rodent Calomys callosus, Rengger 1830 (Rodentia: Cricetidae) is an indigenous inhabitant of the savannah environment found in the central regions of Brazil. The aim of the present work was to evaluate the histopathological and serological features of C. callosus after inoculation with the Pb18 strain of P. brasiliensis. Furthermore, A/Sn and B10.A mice strains were also tested to compare the results obtained in C. callosus to these well-established experimental models of resistance and susceptibility respectively. In every instance, survival analysis was performed, and histopathological study of the lungs, liver and spleen was employed to investigate tissue involvement, degree of inflammation and fungal presence. Levels of antibodies to P. brasiliensis were measured by using an enzyme-linked immunosorbent assay after 4 weeks and at the advanced stage of infection. The mortality rate was proportional to inoculation dose in all groups, but overall it was much superior in C. callosus than in the B10.A-susceptible mice. Macroscopical and microscopical pathological alterations were also more extensive and remarkable for C. callosus, once again proportional to inoculation dose, but more noticeable differences among the studied groups were found with 0.6x10(5) inoculum. In addition, the serological profile of C. callosus was similar to that found for B10.A-susceptible mice. Infection of C. callosus with 0.6x10(8) Pb18 inoculum resulted in more serious illness, and it decreased in severity in proportion to the inoculum dose. This difference was more pronounced in C. callosus, and the clinical, serological and pathological findings in this animal were more intense and precocious compared with the B10.A-susceptible mice. The present results suggest that C. callosus is a

  6. DNA barcoding of Murinae (Rodentia: Muridae) and Arvicolinae (Rodentia: Cricetidae) distributed in China.

    PubMed

    Li, Jing; Zheng, Xin; Cai, Yansen; Zhang, Xiuyue; Yang, Min; Yue, Bisong; Li, Jing

    2015-01-01

    Identification of rodents is very difficult mainly due to high similarities in morphology and controversial taxonomy. In this study, mitochondrial cytochrome oxidase subunit I (COI) was used as DNA barcode to identify the Murinae and Arvicolinae species distributed in China and to facilitate the systematics studies of Rodentia. In total, 242 sequences (31 species, 11 genera) from Murinae and 130 sequences (23 species, 6 genera) from Arvicolinae were investigated, of which 90 individuals were novel. Genetic distance, threshold method, tree-based method, online BLAST and BLOG were employed to analyse the data sets. There was no obvious barcode gap. The average K2P distance within species and genera was 2.10% and 12.61% in Murinae, and 2.86% and 11.80% in Arvicolinae, respectively. The optimal threshold was 5.62% for Murinae and 3.34% for Arvicolinae. All phylogenetic trees exhibited similar topology and could distinguish 90.32% of surveyed species in Murinae and 82.60% in Arvicolinae with high support values. BLAST analyses yielded similar results with identification success rates of 92.15% and 93.85% for Murinae and Arvicolinae, respectively. BLOG successfully authenticated 100% of detected species except Leopoldamys edwardsi based on the latest taxonomic revision. Our results support the species status of recently recognized Micromys erythrotis, Eothenomys tarquinius and E. hintoni and confirm the important roles of comprehensive taxonomy and accurate morphological identification in DNA barcoding studies. We believe that, when proper analytic methods are applied or combined, DNA barcoding could serve as an accurate and effective species identification approach for Murinae and Arvicolinae based on a proper taxonomic framework.

  7. Evolutionary story of a satellite DNA from Phodopus sungorus (Rodentia, Cricetidae).

    PubMed

    Paço, Ana; Adega, Filomena; Meštrović, Nevenka; Plohl, Miroslav; Chaves, Raquel

    2014-10-21

    With the goal to contribute for the understanding of satellite DNA evolution and its genomic involvement, in this work it was isolated and characterized the first satellite DNA (PSUcentSat) from Phodopus sungorus (Cricetidae). Physical mapping of this sequence in P. sungorus showed large PSUcentSat arrays located at the heterochromatic (peri)centromeric region of five autosomal pairs and Y-chromosome. The presence of orthologous PSUcentSat sequences in the genomes of other Cricetidae and Muridae rodents was also verified, presenting however, an interspersed chromosomal distribution. This distribution pattern suggests a PSUcentSat-scattered location in an ancestor of Muridae/Cricetidae families, that assumed afterwards, in the descendant genome of P. sungorus a restricted localization to few chromosomes in the (peri)centromeric region. We believe that after the divergence of the studied species, PSUcentSat was most probably highly amplified in the (peri)centromeric region of some chromosome pairs of this hamster by recombinational mechanisms. The bouquet chromosome configuration (prophase I) possibly displays an important role in this selective amplification, providing physical proximity of centromeric regions between chromosomes with similar size and/or morphology. This seems particularly evident for the acrocentric chromosomes of P. sungorus (including the Y-chromosome), all presenting large PSUcentSat arrays at the (peri)centromeric region. The conservation of this sequence in the studied genomes and its (peri)centromeric amplification in P. sungorus strongly suggests functional significance, possibly displaying this satellite family different functions in the different genomes. The verification of PSUcentSat transcriptional activity in normal proliferative cells suggests that its transcription is not stage-limited, as described for some other satellites.

  8. Chromosomal evolution of Arvicolinae (Cricetidae, Rodentia). III. Karyotype relationships of ten Microtus species.

    PubMed

    Lemskaya, Natalia A; Romanenko, Svetlana A; Golenishchev, Feodor N; Rubtsova, Nadezhda V; Sablina, Olga V; Serdukova, Natalya A; O'Brien, Patricia C M; Fu, Beiyuan; Yiğit, Nuri; Ferguson-Smith, Malcolm A; Yang, Fengtang; Graphodatsky, Alexander S

    2010-06-01

    The genus Microtus consists of 65 extant species, making it one of the rodentia genera with the highest number of species. The extreme karyotype diversification in Microtus has made them an ideal species group for comparative cytogenetics and cytotaxonomy. Conventional comparative cytogenetic studies in Microtus have been based mainly on chromosomal banding patterns; the number of Microtus species examined by molecular cytogenetics-cross-species chromosome painting-is limited. In this study, we used whole chromosome painting probes of the field vole Microtus agrestis to detect regions of homology in the karyotypes of eight Microtus species. For almost all investigated species, species-specific associations of conserved chromosomal segments were revealed. Analysis of data obtained here and previously published data allowed us to propose that the ancestral Microtus species had a 2n = 54 karyotype, including two associations of field vole chromosomal segments (MAG 1/17 and 2/8). Further mapping of the chromosome rearrangements onto a molecular phylogenetic tree allows the reconstruction of a karyotype evolution pathway in the Microtus genus.

  9. Rediscovery and New Morphological Data on Two Hassalstrongylus (Nematoda: Heligmonellidae) Coparasitic in the Marsh Rat Holochilus chacarius (Rodentia: Cricetidae) from Argentina.

    PubMed

    Digiani, María Celina; Notarnicola, Juliana; Navone, Graciela T

    2015-10-01

    Two species of Hassalstrongylus Durette-Desset, 1971, coparasitic in Holochilus chacarius Thomas (Rodentia, Cricetidae) and not recorded since their original description in 1937, were newly found in their type host and locality. Hassalstrongylus mazzai (Freitas, Lent and Almeida, 1937) and Hassalstrongylus argentinus (Freitas, Lent and Almeida, 1937) were obtained from Ho. chacarius from 2 different populations: one from Salta Province (northwest Argentina) and another from Chaco Province (northeast Argentina). The species described as Heligmonoides mazzai Freitas, Lent and Almeida, 1937 had been transferred to Hassalstrongylus even though its synlophe had never been studied. We provide the first descriptions and illustrations of the synlophe of males and females of Hassalstrongylus mazzai and the female of H. argentinus and account for morphological and metrical variability. We confirm, through the study of the synlophe, the placement of Hassalstrongylus mazzai in the genus Hassalstrongylus and designate neotypes for the species because the type material deposited by the authors could not be found. Females of both species were morphologically very similar, and a principal components analysis (PCA) performed on some morphometrical characters showed that the body length, uterus length, and an unexpected character as the number of eggs were useful characters in the discrimination of both species.

  10. A new species of Syphacia (Seuratoxyuris) (Nematoda: Oxyuridae) from Sooretamys angouya Fischer, 1814 (Rodentia: Cricetidae) in Argentina.

    PubMed

    Robles, María del Rosario; Panisse, Guillermo; Navone, Graciela Teresa

    2014-11-01

    Syphacia (Seuratoxyuris) hugoti n. sp. (Nematoda: Oxyuridae) is described from the cecum of Sooretamys angouya (Cricetidae: Sigmodontinae: Oryzomyini) captured in Formosa Province, Argentina. The diagnosis of the subgenus is emended, and the new species is separated from eight congeners by the distribution of submedian papillae and amphids, shape of the cephalic plate, presence of deirids, absence of cervical and lateral alae, length of the spicule, structure of the accessory hook of the gubernaculum and distance of excretory pore and vulva from the anterior extremity. The analysis suggests that S. (Se.) oryzomyos should be removed from Seuratoxyuris and redesignated as S. (Syphacia) oryzomyos n. comb. To date, of the species of Syphacia found in South and North American, 7 parasitize Oryzomyini rodents, of which two are distributed in Argentina. The present study constitutes the first record of the subgenus Seuratoxyuris from Argentina and the third record of a Syphacia species from rodents of the tribe Oryzomyini.

  11. Cytogenetics and karyosystematics of Oryzomys albigularis (Rodentia, Cricetidae) from Venezuela.

    PubMed

    Aguilera, M; Pérez-Zapata, A; Martino, A

    1995-01-01

    Several authors have proposed that Oryzomys albigularis constitutes a supraspecific complex and that chromosomal pericentromeric inversions have played a fundamental role in the diversifying process. With the purpose of clarifying the unclear taxonomic situation of the nominal forms of O. albigularis living in Venezuela, a cytogenetic study was carried out on individuals from five different localities along the Andean range and the Cordillera de la Costa. All of the individuals examined showed a diploid number (2n) of 66 chromosomes, but there were differences in the number of autosomal arms (FN = 90, 92, and 104) and in the morphology of the X chromosome (metacentric or acrocentric). The C-banding pattern was similar in all populations, autosomal heterochromatin was restricted to the centromere, and the Y chromosome was the only one that had completely heterochromatic arms. G-banding was useful in making arm-to-arm comparison between the FN = 90 and FN = 104 karyomorphs; 23 shared pairs were found, 7 pairs differed due to pericentric inversions, and 3 pairs had no correspondence. We postulate that these karyomorphs probably correspond to allospecies, and that the specific denominations must correspond to two previously recognized populations of sigmodontine rodents: O. caracolus Thomas 1914 (2n = 66, FN = 90), for the populations from the Cordillera de la Costa, and O. meridensis Thomas 1894 (2n = 66, FN = 104), for the populations distributed between the middle and extreme north of the Andean range. The specific denomination for the populations of animals from the southern portion of the Andean range (Oryzomys sp., 2n = 66, FN = 92) is still to be determined.

  12. Chromosomal evolution in Rodentia.

    PubMed

    Romanenko, S A; Perelman, P L; Trifonov, V A; Graphodatsky, A S

    2012-01-01

    Rodentia is the most species-rich mammalian order and includes several important laboratory model species. The amount of new information on karyotypic and phylogenetic relations within and among rodent taxa is rapidly increasing, but a synthesis of these data is currently lacking. Here, we have integrated information drawn from conventional banding studies, recent comparative painting investigations and molecular phylogenetic reconstructions of different rodent taxa. This permitted a revision of several ancestral karyotypic reconstructions, and a more accurate depiction of rodent chromosomal evolution.

  13. Chromosomal variation in Argentine populations of Akodon montensis Thomas, 1913 (Rodentia, Cricetidae, Sigmodontinae)

    PubMed Central

    Malleret, Matías Maximiliano; Labaroni, Carolina Alicia; García, Gabriela Verónica; Ferro, Juan Martín; Martí, Dardo Andrea; Lanzone, Cecilia

    2016-01-01

    Abstract The genus Akodon Meyen, 1833 is one of the most species-rich among sigmodontine rodents and has great chromosome variability. Akodon montensis has a relatively broad distribution in South America, and Argentine populations are located in the southernmost region of its range. Brazilian populations have important chromosomal variability, but cytogenetic data from Argentina are scarce. We performed a chromosome characterization of natural populations of Akodon montensis using conventional staining, C-banding, Ag-NORs and base-specific fluorochromes. A total of 31 specimens from five localities of Misiones Province, in Argentina, were analyzed. The 2n=24 chromosomes was the most frequently observed karyotype. However, five individuals presented 25 chromosomes due to a supernumerary B-chromosome; and one individual had 2n=26 due to one B plus a trisomy for chromosome 11. Additionally, two XY females and two variants of the X chromosomes were found. C-positive centromeric bands occurred in all chromosomes; additional C-bands were observed in some autosomes, the X, Y and B chromosomes. Ag-NORs were observed in five autosomes, and the B chromosome was frequently marked. Fluorochrome banding was similar among karyotypes of the analyzed populations. Comparisons of cytogenetic data among populations of Argentina and Brazil showed the presence of high intraspecific variability in Akodon montensis and some differences among regions. PMID:27186343

  14. [Supraspecies relationships in the subfamily (Rodentia, Cricetidae, Arvicolinae): unexpexted result of nuclear genes analysis].

    PubMed

    Abramson, N I; Lebedev, V S; Tesakov, A S; Bannikova, A A

    2009-01-01

    Phylogenetic analysis of supraspecies relationships in one of the most young and species rich group of myomorph rodents - subfamily Arvicolinae was carried out on the base of two nuclear genes. Results have shown that mole-voles - Ellobiusini, steppe voles - (Lagurini) and grey voles (Arvicolini) are sister groups. This divergence is the most late, third wave of radiation within the family. The sister clade to this group is the tribe of red-back voles - Myodini (=Clethrionomini) - "second radiation". The order of divergence for earliest radiation remains still unresolved (Ondatrini, Prometheomyini, Dicrostonychini, Lemmini). New data on the close relationships of mole voles, grey voles and steppe voles are unexpected one and contradict to the conventional views. The latter ideas on the significant ancientry and separation of Ellobiusini from all other voles is based on extreme simplicity of their rooted molars and very peculiar structure of the skull and postcranial skeleton. However, many of these characters most likely indicate on significant degree of adaptation to the subterranean life and have no phylogenetic signal.

  15. No differences in the Sry gene between males and XY females in Akodon (Rodentia, Cricetidae).

    PubMed

    Sánchez, A; Marchal, J A; Romero-Fernández, I; Pinna-Senn, E; Ortiz, M I; Bella, José L; Lisanti, J A

    2010-01-01

    Several species of the South American genus Akodon present fully fertile XY females besides XX ones. To analyze the possibility of a Sry mutation as the cause of sex reversal in A. azarae and A. boliviensis, we determined the sequence of the Sry gene in 2 males and 3 XY females from each of these species. The Sry gene sequence was also studied in A. dolores, a species that does not have XY females. In inter-specific comparisons, the percentage identities with respect to the region analyzed varied between 96.8% and 97.9%. An ORF of 543 nucleotides was identified, and the predicted Sry proteins comprised 180 amino acids, with an HMG domain of 83 amino acids. Our results indicate that female sex reversal in A. azarae and A. boliviensis cannot be explained by sequence differences in the Sry region analyzed here, which includes the complete ORF and, together with previous results concerning the inheritance of the XY condition, show that Sry mutation is not the basis of sex reversal.

  16. Karyotypic variation in the Andean rodent Phyllotisxanthopygus (Waterhouse, 1837) (Rodentia, Cricetidae, Sigmodontinae).

    PubMed

    Labaroni, Carolina Alicia; Malleret, Matías Maximiliano; Novillo, Agustina; Ojeda, Agustina; Rodriguez, Daniela; Cuello, Pablo; Ojeda, Ricardo; Dardo Martí; Lanzone, Cecilia

    2014-01-01

    Phyllotisxanthopygus (Waterhouse, 1837) is an Andean rodent endemic to South America. Despite its wide geographical distribution in Argentina, few individuals have been studied on the cytogenetic level and only through conventional staining. In this work, chromosome characterization of Argentine samples of this species was performed using solid staining, C-banding and base-specific fluorochromes. Twenty two specimens were analyzed, collected in the provinces of Jujuy, Catamarca, and the north and south of Mendoza. All studied specimens showed 2n=38, having mostly the bi-armed autosomes, metacentric or submetacentric. Fundamental Number varied between 70 and 72. These changes were due to the presence of chromosome heteromorphisms in individuals from southern Mendoza and Jujuy. C-banding revealed pericentromeric blocks of constitutive heterochromatin in most chromosomes. Acrocentric chromosomes involved in heteromorphisms showed high variation in the amount of heterochromatin within and among populations. Additionally, banding with fluorochromes (DAPI and chromomycin A3) revealed homologous localization of AT and GC rich regions among chromosomes of the different populations analyzed. Comparisons among heteromorphic pairs suggested, however, that the variation might be the result of complex chromosome rearrangements, involving possibly amplifications and/or deletions of heterochromatic segments. These results are in accordance with molecular studies that indicate genetic variability within and among the populations of this taxon.

  17. First cytogenetic information for Drymoreomys albimaculatus (Rodentia, Cricetidae), a recently described genus from Brazilian Atlantic Forest

    PubMed Central

    Suárez-Villota, Elkin Y.; Di-Nizo, Camilla B.; Neves, Carolina L.; Silva, Maria José de Jesus

    2013-01-01

    Abstract The recently described taxon Drymoreomys albimaculatus is endemic to the Brazilian Atlantic Forest and its biology and genetics are still poorly known. Herein, we present, for the first time, the karyotype of the species using classical and molecular cytogenetics, which showed 2n=62, FN=62, and interstitial telomeric signals at the sex chromosomes. Nuclear and mitochondrial DNA sequences from the two karyotyped individuals verify the taxonomic identity as the recently described Drymoreomys albimaculatus and confirm the relationship of the species with other Oryzomyini. Additionally, external morphological information is provided. PMID:23794904

  18. Chromosomal variation in Argentine populations of Akodon montensis Thomas, 1913 (Rodentia, Cricetidae, Sigmodontinae).

    PubMed

    Malleret, Matías Maximiliano; Labaroni, Carolina Alicia; García, Gabriela Verónica; Ferro, Juan Martín; Martí, Dardo Andrea; Lanzone, Cecilia

    2016-01-01

    The genus Akodon Meyen, 1833 is one of the most species-rich among sigmodontine rodents and has great chromosome variability. Akodon montensis has a relatively broad distribution in South America, and Argentine populations are located in the southernmost region of its range. Brazilian populations have important chromosomal variability, but cytogenetic data from Argentina are scarce. We performed a chromosome characterization of natural populations of Akodon montensis using conventional staining, C-banding, Ag-NORs and base-specific fluorochromes. A total of 31 specimens from five localities of Misiones Province, in Argentina, were analyzed. The 2n=24 chromosomes was the most frequently observed karyotype. However, five individuals presented 25 chromosomes due to a supernumerary B-chromosome; and one individual had 2n=26 due to one B plus a trisomy for chromosome 11. Additionally, two XY females and two variants of the X chromosomes were found. C-positive centromeric bands occurred in all chromosomes; additional C-bands were observed in some autosomes, the X, Y and B chromosomes. Ag-NORs were observed in five autosomes, and the B chromosome was frequently marked. Fluorochrome banding was similar among karyotypes of the analyzed populations. Comparisons of cytogenetic data among populations of Argentina and Brazil showed the presence of high intraspecific variability in Akodon montensis and some differences among regions.

  19. Reservoir competence of Microtus pennsylvanicus (Rodentia: Cricetidae) for the Lyme disease spirochete, Borrelia burgdorferi

    USGS Publications Warehouse

    Markowski, D.; Ginsberg, H.S.; Hyland, K.E.; Hu, R.

    1998-01-01

    The reservoir competence of the meadow vole, Microtus pennsylvanicus Ord, for the Lyme disease spirochete, Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt & Brenner was established on Patience Island, RI. Meadow voles were collected from 5 locations throughout Rhode Island. At 4 of the field sites, M. pennsylvanicus represented only 4.0% (n = 141) of the animals captured. However, on Patience Island, M. pennsylvanicus was the sole small mammal collected (n = 48). Of the larval Ixodes scapularis Say obtained from the meadow voles on Patience Island, 62% (n = 78) was infected with B. burgdorferi. Meadow voles from all 5 locations were successfully infected with B. burgdorferi in the laboratory and were capable of passing the infection to xenodiagnostic I. scapularis larvae for 9 wk. We concluded that M. pennsylvanicus was physiologically capable of maintaining B. burgdorferi infection. However, in locations where Peromyscus leucopus (Rafinesque) is abundant, the role of M. pennsylvanicus as a primary reservoir for B. burgdorferi was reduced.

  20. Nitric oxide production by Peromyscus yucatanicus (Rodentia) infected with Leishmania (Leishmania) mexicana

    PubMed Central

    Loría-Cervera, Elsy Nalleli; Sosa-Bibiano, Erika Ivett; Villanueva-Lizama, Liliana Estefanía; Van Wynsberghe, Nicole Raymonde; Canto-Lara, Silvia Beatriz; Batún-Cutz, José Luis; Andrade-Narváez, Fernando José

    2013-01-01

    Peromyscus yucatanicus (Rodentia: Cricetidae) is a primary reservoir of Leishmania (Leishmania) mexicana (Kinetoplastida: Trypanosomatidae). Nitric oxide (NO) generally plays a crucial role in the containment and elimination of Leishmania. The aim of this study was to determine the amount of NO produced by P. yucatanicus infected with L. (L.) mexicana. Subclinical and clinical infections were established in P. yucatanicus through inoculation with 1 x 102 and 2.5 x 106 promastigotes, respectively. Peritoneal macrophages were cultured alone or co-cultured with lymphocytes with or without soluble Leishmania antigen. The level of NO production was determined using the Griess reaction. The amount of NO produced was significantly higher (p ≤ 0.0001) in co-cultured macrophages and lymphocytes than in macrophages cultured alone. No differences in NO production were found between P. yucatanicus with subclinical L. (L.) mexicana infections and animals with clinical infections. These results support the hypothesis that the immunological mechanisms of NO production in P. yucatanicus are similar to those described in mouse models of leishmaniasis and, despite NO production, P. yucatanicus is unable to clear the parasite infection. PMID:23579796

  1. A new species of Argyromys (Rodentia, Mammalia) from the Oligocene of the Valley of Lakes (Mongolia): Its importance for palaeobiogeographical homogeneity across Mongolia, China and Kazakhstan

    PubMed Central

    Maridet, Olivier; Zhang, Zhaoqun; Daxner-Höck, Gudrun

    2017-01-01

    We describe a new species of Rodentia (Mammalia), Argyromys cicigei sp. nov. from Toglorhoi (fossil bed TGW-A/2a) in Mongolia and Ulantatal (fossil beds UTL 1 and UTL 7) in China. Its tooth morphology differs from the type species Argyromys aralensis from Akespe in Kazakhstan by smaller size and simpler structures. Argyromys has been assigned in different families of Muroidea, such as Tachyoryctoididae and Spalacidae. However, the presence of common characters indicates a closer relationship of Argyromys with the genera of Cricetidae s.l. (subfamilies Eucricetodontinae; Cricetopinae; Cricetodontinae and Gobicricetodontinae among others) from Asia than with the earliest representatives of Spalacidae or the endemic Tachyoryctoididae. Argyromys cicigei sp. nov. possesses a simple anterocone and anteroconid in the upper and lower first molars, respectively, which is characteristic for Cricetidae s.l. It has a flat occlusal surface in worn specimens; weakly-developed posterolophs; an oblique protolophule and metaloph on the upper molars and it lacks a labial anterolophid on the m1. These traits are also typical of the Oligocene genera Aralocricetodon and Plesiodipus, included in the subfamilies Cricetodontinae and Gobicricetodontinae respectively. The cladistic analysis performed here supports this hypothesis. The clade formed by Argyromys species is grouped with other cricetid taxa (s.l). Spalacids, however, form a different clade, as do the tachyoryctoids. Previous authors state that the Aral Formation (Kazakhstan) should be dated to the Oligocene instead of the Miocene, based on the presence of several taxa. The finds of Argyromys in both regions supports the statement that they are closer in age than previously thought. The occurrence of Argyromys in Kazakhstan, Mongolia and China evidences the biogeographic unity of the Central Asian bioprovince during the Oligocene. PMID:28328975

  2. A new species of Argyromys (Rodentia, Mammalia) from the Oligocene of the Valley of Lakes (Mongolia): Its importance for palaeobiogeographical homogeneity across Mongolia, China and Kazakhstan.

    PubMed

    López-Guerrero, Paloma; Maridet, Olivier; Zhang, Zhaoqun; Daxner-Höck, Gudrun

    2017-01-01

    We describe a new species of Rodentia (Mammalia), Argyromys cicigei sp. nov. from Toglorhoi (fossil bed TGW-A/2a) in Mongolia and Ulantatal (fossil beds UTL 1 and UTL 7) in China. Its tooth morphology differs from the type species Argyromys aralensis from Akespe in Kazakhstan by smaller size and simpler structures. Argyromys has been assigned in different families of Muroidea, such as Tachyoryctoididae and Spalacidae. However, the presence of common characters indicates a closer relationship of Argyromys with the genera of Cricetidae s.l. (subfamilies Eucricetodontinae; Cricetopinae; Cricetodontinae and Gobicricetodontinae among others) from Asia than with the earliest representatives of Spalacidae or the endemic Tachyoryctoididae. Argyromys cicigei sp. nov. possesses a simple anterocone and anteroconid in the upper and lower first molars, respectively, which is characteristic for Cricetidae s.l. It has a flat occlusal surface in worn specimens; weakly-developed posterolophs; an oblique protolophule and metaloph on the upper molars and it lacks a labial anterolophid on the m1. These traits are also typical of the Oligocene genera Aralocricetodon and Plesiodipus, included in the subfamilies Cricetodontinae and Gobicricetodontinae respectively. The cladistic analysis performed here supports this hypothesis. The clade formed by Argyromys species is grouped with other cricetid taxa (s.l). Spalacids, however, form a different clade, as do the tachyoryctoids. Previous authors state that the Aral Formation (Kazakhstan) should be dated to the Oligocene instead of the Miocene, based on the presence of several taxa. The finds of Argyromys in both regions supports the statement that they are closer in age than previously thought. The occurrence of Argyromys in Kazakhstan, Mongolia and China evidences the biogeographic unity of the Central Asian bioprovince during the Oligocene.

  3. Characterization of the satellite DNA Msat-160 from species of Terricola (Microtus) and Arvicola (Rodentia, Arvicolinae).

    PubMed

    Acosta, Manuel J; Marchal, Juan A; Fernández-Espartero, Cecilia; Romero-Fernández, Ismael; Rovatsos, Michail T; Giagia-Athanasopoulou, Eva B; Gornung, Ekaterina; Castiglia, Riccardo; Sánchez, Antonio

    2010-10-01

    In the subfamily Arvicolinae (Cricetidae, Rodentia) the satellite DNA Msat-160 has been so far described in only some species from the genus Microtus and in one species from another genus, Chionomys nivalis. Here we cloned and characterized this satellite in two new arvicoline species, Microtus (Terricola) savii and Arvicola amphibius (terrestris). We have also demonstrated, by PCR and FISH, its existence in the genomes of several other species from both genera. These results suggest that Msat-160 already occurred in the common ancestor of the four genera/subgenera of Arvicolinae (Microtus, Chionomys, Arvicola, and Terricola). In Arvicola and Terricola, Msat-160 showed the basic monomer length of 160 bp, although a higher-order repeat (HORs) of 640 bp could have been probably replacing the original monomeric unit in A. a. terrestris. Msat-160 was localized by FISH mostly on the pericentromeric regions of the chromosomes, but the signal intensity and the number of carrier chromosomes varied extremely even between closely related species, resulting in a species-specific pattern of chromosomal distribution of this satellite. Such a variable pattern most likely is a consequence of a rapid amplification and contraction of particular repeats in the pericentromeric regions of chromosomes. In addition, we proposed that the rapid variation of pericentromeric repeats is strictly related to the prolific species radiation and diversification of karyotypes that characterize Arvicolinae lineage. Finally, we performed phylogenetic analysis in this group of related species based on Msat-160 that results to be in agreement with previously reported phylogenies, derived from other molecular markers.

  4. Ultrastructure of the spermatozoon of the trematode Notocotylus noyeri (Digenea: Notocotylidae), a parasite of Microtus arvalis (Rodentia: Cricetidae).

    PubMed

    Ibnou Ndiaye, Papa; Torres, Jordi; Eira, Catarina; Shimalov, Vladimir V; Miquel, Jordi

    2015-01-01

    In the present paper, we describe the ultrastructure of the spermatozoon of the notocotylid Notocotylus noyeri (Joyeux, 1922) by means of transmission electron microscopy. The mature spermatozoon of N. noyeri exhibits the general pattern described in the majority of digeneans: two axonemes of the 9 + "1" pattern of the Trepaxonemata, nucleus, mitochondria, parallel cortical microtubules, spine-like bodies and ornamentation of the plasma membrane. The glycogenic nature of the electron-dense granules was evidenced applying the test of Thiéry. The ultrastructural features of the spermatozoon of N. noyeri present some differences in relation to those of the Pronocephalidea described until now, but confirm a general pattern for the Notocotylidae, namely a spermatozoon with two mitochondria and an anterior region with ornamentation of the plasma membrane associated with spine-like bodies. The posterior extremity of the spermatozoon exhibits only some microtubules after the disorganisation of the second axoneme. The present study confirms that some ultrastructural characters of the sperm cell such as the presence or absence of lateral expansions, the number of mitochondria and the morphology of both anterior and posterior spermatozoon extremities are useful for phylogenetic purposes within the Pronocephaloidea. Thus, unlike notocotylids, pronocephalids exhibit external ornamentation and a lateral expansion in the anterior spermatozoon region. Moreover, notocotylid spermatozoa present two mitochondria, whereas pronocephalid spermatozoa exhibit a single mitochondrion. Finally, pronocephalids are characterised by a type 2 posterior spermatozoon extremity, whereas notocotylids exhibit a type 3 posterior spermatozoon extremity.

  5. Analysis of meiotic chromosome structure and behavior in Robertsonian heterozygotes of Ellobius tancrei (Rodentia, Cricetidae): a case of monobrachial homology

    PubMed Central

    Matveevsky, Sergey; Bakloushinskaya, Irina; Tambovtseva, Valentina; Romanenko, Svetlana; Kolomiets, Oxana

    2015-01-01

    Abstract Synaptonemal complex (SC) chains were revealed in semisterile intraspecific F1 hybrids of Ellobius tancrei Blasius, 1884 (2n = 49, NF=56 and 2n=50, NF=56), heterozygous for Robertsonian (Rb) translocations. Chains were formed by Rb submetacentrics with monobrachial homology. Chromosome synapsis in spermatocytes of these hybrids was disturbed, apparently because of the problematic release of the chromosomes from the SC chains. These hybrids suffer from low fertility, and our data support the opinion that this is because a formation of Rb metacentrics with monobrachial homology within different races of the same species might be an initial event for the divergence of chromosomal forms. PMID:26752380

  6. Descriptive morphometry and stereology of the tubular compartment in the wild rodent Hylaeamys megacephalus (Rodentia: Cricetidae) from Central Brazil.

    PubMed

    de Melo, Fabiana Cristina Silveira Alves; de Sousa, Tatiane Pires; Costa, Kyvia Lugate C; da Matta, Sérgio Luis P; de Melo, Fabiano Rodrigues; Santa-Rita, Ricardo de Mattos

    2013-04-01

    Information on reproductive characteristics of wild rodents is scarce in the literature. This study aimed to assess the testis morphometry and stereology of Hylaeamys megacephalus. We used five animals in the study, captured in forest fragments in southwestern Goias State, between April and August 2009. The testes were fixed in Karnovsky solution, dehydrated, and embedded in methacrylate. Two-micrometer-thick sections from each sample were stained with toluidine blue/sodium borate 1%. Images of the testicular parenchyma were obtained from photomicroscope and morphometric and stereological analyses were carried out using the Image Pro-Plus software. The average body weight observed in the specimens of H. megacephalus in the study was 47.84 g, of which, 0.40% is allocated to the gonads (GSI) and 0.36% to the seminiferous tubules (TSI). These parameters suggest promiscuous reproductive behavior, of the polyandrous type, favoring males with higher sperm production and consequently, larger testes. The volume density of the seminiferous tubules was 94.46%, which represented a volume of 0.18 mL. The volume density and volume of the interstitium were 5.54% and 0.011 mL, respectively. The diameter of the seminiferous tubules was 206.5 μm and the height of seminiferous epithelium was 71.27 μm. H. megacephalus presents 5.06 m of seminiferous tubules and an average of 27.96 m of seminiferous tubules per gram of testis. The mitotic and meiotic indexes showed losses of 85 and 42%, respectively and an overall loss of 90% over the full spermatogenic process. The number of Sertoli cells per testis and per gram of testis was 7.8×10(6) and 95.28×10(6), respectively. Most of the morphometric parameters evaluated in H. megacephalus in this study are within the range of values described for most mammals.

  7. Shippingport, Kentucky, is the type locality for the white-footed mouse, Peromyscus leucopus (Rafinesque, 1818) (Mammalia: Rodentia: Cricetidae)

    USGS Publications Warehouse

    Woodman, Neal

    2015-01-01

    The white-footed mouse, Musculus leucopus Rafinesque, 1818 (= Peromyscus leucopus), is a common small mammal that is widespread in the eastern and central United States. Its abundance in many habitats renders it ecologically important, and its status as a reservoir for hantavirus and Lyme disease gives the species medical and economic significance. The recognition of two cytotypes and up to 17 morphological subspecies of P. leucopus indicates considerable variation in the species, and to understand this variation, it is important that the nominate subspecies be adequately defined so as to act as a standard for comparison. Relevant to this standard for the white-footed mouse is its type locality, which has generally been accepted to be either the vague "pine barrens of Kentucky" or the mouth of the Ohio River. Newly assembled information regarding the life and travels of Constantine S. Rafinesque, the North American naturalist who described P. leucopus, establishes that Rafinesque observed this species in July 1818 while visiting Shippingport, Kentucky, which is now within the city limits of Louisville, Jefferson Co., Kentucky. Shippingport is therefore the actual type locality for this species.

  8. Encephalitozoon infections in Rodentia and Soricomorpha in Japan.

    PubMed

    Tsukada, Ryusuke; Tsuchiyama, Atsuko; Sasaki, Mizuki; Park, Chun-Ho; Fujii, Yoshito; Takesue, Masataka; Hatai, Hitoshi; Kudo, Noboru; Ikadai, Hiromi

    2013-11-15

    Encephalitozoon is an obligate intracellular microsporidian parasite that infects a wide range of mammalian hosts. In this study, we used nested PCR to investigate the presence of Encephalitozoon infection in Rodentia and Soricomorpha in Japan. We attempted to amplify and sequence Encephalitozoon-specific DNA from brain and viscera samples of 180 animals collected between 2008 and 2010. Forty-three samples (23.9%) from the orders Rodentia and Soricomorpha were positive for Encephalitozoon. This study is the first report of Encephalitozoon infection in Rodentia and Soricomorpha in Japan, and our findings suggest that these hosts may play a role in the spread of microsporidian spores in the environment.

  9. Pterygodermatites (Paucipectines) baiomydis n. sp. (Nematoda: Rictulariidae), a parasite of Baiomys taylori (Cricetidae)

    PubMed Central

    Lynggaard, Christina; García-Prieto, Luis; Guzmán-Cornejo, Carmen; Osorio-Sarabia, David

    2014-01-01

    Pterygodermatites (Paucipectines) baiomydis n. sp., an intestinal parasite of the northern pygmy mouse, Baiomys taylori (Cricetidae), collected in La Yerbabuena, Colima, Mexico, is described herein. Specimens were studied using light and scanning electronic microscopy. This is the 19th species of the subgenus Paucipectines described worldwide and the fourth collected in Mexico. It is differentiated from the remaining species in the subgenus by having 25 perioral denticles, arranged in a triangle (seven on each lateroventral margin, and eleven on the dorsal margin), and 10 pairs of caudal papillae. PMID:25375029

  10. Nematofauna of Rodents of the Families Heteromyidae and Cricetidae from the Mexican Plateau.

    PubMed

    Iturbe-Morgado, José Carlos; Falcón-Ordaz, Jorge; Lira-Guerrero, Georgina; Fernández, Jesús A; Acosta, Roxana

    2017-02-01

    As a part of an ongoing project to inventory the helminth parasites of rodents in Mexico, 85 specimens of 2 families of rodents were collected from the Mexican Plateau: Cricetidae ( Neotoma sp., Neotoma leucodon , Onychomys arenicola , Peromyscus sp., Peromyscus eremicus , and Reithrodontomys sp.) and Heteromyidae ( Chaetodipus sp., Chaetodipus eremicus , Chaetodipus hispidus , Dipodomys merriami , Dipodomys ordii , Dipodomys ornatus, Dipodomys spectabilis , Liomys irroratus , Perognathus sp., and Perognathus flavus ). A total of 13 taxa of helminths were found: Heteromyoxyuris longejector, Heteromyoxyuris otomii, Heteromyoxyuris sp., Onchocercidae gen. sp. 1 and sp. 2, Physalopteridae gen. sp., Protospirura dipodomis, Pterygodermatites dipodomis, Subulura sp., Syphacia sp., Trichuris dipodomis, Vexillata liomyos, and Vexillata armande. The highest species richness was recorded in D. merriami (7 taxa). This study is the first report of nematodes from O. arenicola (Physalopteridae gen. sp.) and C. eremicus (H. longejector) and for V. liomyos from D. merriami . All reports of these species of nematodes represent new collection localities in Mexico.

  11. Chromosomal evolution of Arvicolinae (Cricetidae, Rodentia). II. The genome homology of two mole voles (genus Ellobius), the field vole and golden hamster revealed by comparative chromosome painting.

    PubMed

    Romanenko, Svetlana A; Sitnikova, Natalia A; Serdukova, Natalya A; Perelman, Polina L; Rubtsova, Nadezhda V; Bakloushinskaya, Irina Yu; Lyapunova, Elena A; Just, Walter; Ferguson-Smith, Malcolm A; Yang, Fengtang; Graphodatsky, Alexander S

    2007-01-01

    Using cross-species chromosome painting, we have carried out a comprehensive comparison of the karyotypes of two Ellobius species with unusual sex determination systems: the Transcaucasian mole vole, Ellobius lutescens (2n = 17, X in both sexes), and the northern mole vole, Ellobius talpinus (2n = 54, XX in both sexes). Both Ellobius species have highly rearranged karyotypes. The chromosomal paints from the field vole (Microtus agrestis) detected, in total, 34 and 32 homologous autosomal regions in E. lutescens and E. talpinus karyotypes, respectively. No difference in hybridization pattern of the X paint (as well as Y paint) probes on male and female chromosomes was discovered. The set of golden hamster (Mesocricetus auratus) chromosomal painting probes revealed 44 and 43 homologous autosomal regions in E. lutescens and E. talpinus karyotypes, respectively. A comparative chromosome map was established based on the results of cross-species chromosome painting and a hypothetical ancestral Ellobius karyotype was reconstructed. A considerable number of rearrangements were detected; 31 and 7 fusion/fission rearrangements differentiated the karyotypes of E. lutescens and E. talpinus from the ancestral Ellobius karyotype. It seems that inversions have played a minor role in the genome evolution of these Ellobius species.

  12. Chromosomal evolution of Arvicolinae (Cricetidae, Rodentia). I. The genome homology of tundra vole, field vole, mouse and golden hamster revealed by comparative chromosome painting.

    PubMed

    Sitnikova, Natalia A; Romanenko, Svetlana A; O'Brien, Patricia C M; Perelman, Polina L; Fu, Beiyuan; Rubtsova, Nadezhda V; Serdukova, Natalya A; Golenishchev, Feodor N; Trifonov, Vladimir A; Ferguson-Smith, Malcolm A; Yang, Fengtang; Graphodatsky, Alexander S

    2007-01-01

    Cross-species chromosome painting has become the mainstay of comparative cytogenetic and chromosome evolution studies. Here we have made a set of chromosomal painting probes for the field vole (Microtus agrestis) by DOP-PCR amplification of flow-sorted chromosomes. Together with painting probes of golden hamster (Mesocricetus auratus) and mouse (Mus musculus), the field vole probes have been hybridized onto the metaphases of the tundra vole (Microtus oeconomus). A comparative chromosome map between these two voles, golden hamster and mouse has been established based on the results of cross-species chromosome painting and G-banding comparisons. The sets of paints from the field vole, golden hamster and mouse identified a total of 27, 40 and 47 homologous autosomal regions, respectively, in the genome of tundra vole; 16, 41 and 51 fusion/fission rearrangements differentiate the karyotype of the tundra vole from the karyotypes of the field vole, golden hamster and mouse, respectively.

  13. Taxonomic revision of the Andean leaf-eared mouse, Phyllotis andium Thomas 1912 (Rodentia: Cricetidae), with the description of a new species.

    PubMed

    Rengifo, Edgardo M; Pacheco, Víctor

    2015-09-16

    The Andean Leaf-eared mouse, Phyllotis andium Thomas 1912, has been considered a widespread medium-size sigmodontine rodent (230 mm of total length and 35 grams approximately) that occurs from Tungurahua, Ecuador, through the Andes, to Lima, Peru. Previous studies performed on Phyllotis noted evidence of morphological geographical variation within the species, which is likely because of the several potential geographical barriers that exist within the distribution range of P. andium. We carried out a taxonomic revision of this species based on qualitative and quantitative morphological analyses of 330 specimens from 92 localities. This included appropriate comparisons with other species of the andium/amicus group and performed molecular analysis based on cytochrome b sequences. As a result, morphologic qualitative analysis suggested the recognition of three different taxa, which are supported by morphologic quantitative and molecular analyses. The three taxa here identified have allopatric distributional ranges separated by important geographic barriers. Following these identification criteria, P. andium is now recognized for the samples from Tungurahua, Ecuador to Huánuco, Peru, and includes melanius and fruticicolus as synonymous; the southern populations from the Ancash and Lima departments, in the western Peruvian Andes, are proposed to represent a new species; and we recognize P. stenops as a valid species with tamborum as a synonym. Finally, we postulate that the diversification of these three species is related to key events in the Andean orogeny.

  14. An integrative appraisal of the diversification in the Atlantic forest genus Delomys (Rodentia: Cricetidae: Sigmodontinae) with the description of a new species.

    PubMed

    Gonçalves, Pablo Rodrigues; de Oliveira, João Alves

    2014-01-30

    Recent taxonomic studies on Neotropical mammals have benefited from the use of genetic data to unravel and recognize species diversity in a number of genera, including the Atlantic forest endemic genus Delomys. However, the success of this approach depends on ability to link genetically identified lineages to species names based on voucher specimens that lack genetic data. Cytogenetic studies in the Atlantic forest endemic rodent genus Delomys have revealed two widespread karyotypes, 2n=72/FN=90 and 2n=82/FN=80, which have been respectively ascribed to Delomys sublineatus (Thomas, 1903) and D. dorsalis (Hensel, 1872). More recently, a third karyotype, 2n=82/FN=86, reported from specimens collected on two montaintops in southeastern Brazil, was interpreted as evidence for a third species, D. collinus Thomas, 1917. This nominal form had originally been described as a subspecies of D. dorsalis from Itatiaia, one of the mountain ranges where the third karyotype was later detected. The detection of two sympatric karyotypes at the type locality of D. collinus in the Itatiaia mountain range, Southeastern Brazil, prompted a reevaluation of the association of karyomorphs and species names. In this paper, we assessed the congruence of molecular (cytochrome b), cytogenetic and morphological characters, to diagnose the species in the genus, including data from recently collected series and type specimens. Our results indicate that the genetic and morphological patterns are largely congruent with the recognition of three species, each of which is karyotypically and morphologically diagnosable. Our morphological analyses of sympatric samples from Itatiaia refute the former association of the 2n=82/FN=86 karyotype with the holotype of D. dorsalis collinus (which is more similar to D. dorsalis with 2n=82/FN=80). Instead, we recognize and describe a new species for the 2n=82/FN=86 populations from the highest altitudinal zones of the Itatiaia and Caparaó mountains. The geographical variation in D. dorsalis is also explored and the status of D. d. collinus is discussed in the light of the molecular and morphological evidence. Finally, we discuss biogeographic hypotheses concerning the disjunct distributions of D. dorsalis and the new species.

  15. Differences in richness and composition of gastrointestinal parasites of small rodents (Cricetidae, Rodentia) in a continental and insular area of the Atlantic Forest in Santa Catarina state, Brazil.

    PubMed

    Kuhnen, V V; Graipel, M E; Pinto, C J C

    2012-08-01

    The first and only study on gastrointestinal parasites of wild rodents in the Island of Santa Catarina was done in 1987. The aim of this study was to identify intestinal parasites from wild rodents in Santo Amaro da Imperatriz and Santa Catariana Island, and to compare the richness and composition of the gastrointestinal parasite community of both areas. Rodents were captured with live traps, and feces were screened using the sedimentation method and optical microscopy. The following species of rodents were captured in the two areas: Akodon montensis, Euryoryzomys russatus, Oligoryzomys nigripes and Nectomys squamipes. In Santo Amaro da Impetratriz, prevalent parasites were: A. montensis (51%), E. russatus (62%), O. nigripes (53%) and N. squamipes (20%). From the Island of Santa Catarina the rodent prevalence rates were: A. montensis (43%), E. russatus (59%), O. nigripes (30%) and N. squamipes (33%) and the collected parasites were: Hymenolepis sp., Longistriata sp., Strongyloides sp., Hassalstrongylus sp., Syphacia sp., Trichomonas sp., Ancylostomidae, Trichuridae, Oxyuridae and Eucoccidiorida. The species richness (10.6 ± 0.7) of the endoparasite comunity in the area located on the continent was higher (p < 0.01) and different (p = 0.001) from that of the area located on the island (6.9 ± 0.5).

  16. Chromosome homologies of the highly rearranged karyotypes of four Akodon species (Rodentia, Cricetidae) resolved by reciprocal chromosome painting: the evolution of the lowest diploid number in rodents.

    PubMed

    Ventura, Karen; O'Brien, Patricia C M; Yonenaga-Yassuda, Yatiyo; Ferguson-Smith, Malcolm A

    2009-01-01

    Traditionally comparative cytogenetic studies are based mainly on banding patterns. Nevertheless, when dealing with species with highly rearranged genomes, as in Akodon species, or with other highly divergent species, cytogenetic comparisons of banding patterns prove inadequate. Hence, comparative chromosome painting has become the method of choice for genome comparisons at the cytogenetic level since it allows complete chromosome probes of a species to be hybridized in situ onto chromosomes of other species, detecting homologous genomic regions between them. In the present study, we have explored the highly rearranged complements of the Akodon species using reciprocal chromosome painting through species-specific chromosome probes obtained by chromosome sorting. The results revealed complete homology among the complements of Akodon sp. n. (ASP), 2n = 10; Akodon cursor (ACU), 2n = 15; Akodon montensis (AMO), 2n = 24; and Akodon paranaensis (APA), 2n = 44, and extensive chromosome rearrangements have been detected within the species with high precision. Robertsonian and tandem rearrangements, pericentric inversions and/or centromere repositioning, paracentric inversion, translocations, insertions, and breakpoints, where chromosomal rearrangements, seen to be favorable, were observed. Chromosome painting using the APA set of 21 autosomes plus X and Y revealed eight syntenic segments that are shared with A. montensis, A. cursor, and ASP, and one syntenic segment shared by A. montensis and A. cursor plus five exclusive chromosome associations for A. cursor and six for ASP chromosome X, except for the heterochromatin region of ASP X, and even chromosome Y shared complete homology among the species. These data indicate that all those closely related species have experienced a recent extensive process of autosomal rearrangement in which, except for ASP, there is still complete conservation of sex chromosomes homologies.

  17. Laelapinae mites (Acari: Parasitiformes: Laelapidae) parasitic of sigmodontine rodents from northern Peru, with the description of a new species from Akodon aerosus (Rodentia: Cricetidae: Sigmodontinae).

    PubMed

    Lareschi, Marcela; Velazco, Paúl M

    2013-04-01

    Laelapine mites are common parasites of sigmodontine rodents in the Neotropics. However, few species are reported from Peru as a result of the low number of mammal surveys that include ectoparasite collections. Herein we report 12 species of mites from northern Peru. From these, 8 are reported for the first time for the country, and 1 is new to science , Androlaepaps aerosus sp. nov., the latter associated exclusively with the sigmodontine Akodon aerosus . Most of the laelapine species were host specific. The new species, included in the Androlaelaps rotundus species group, resembles An. rotundus "sensu stricto" and An. ulysespardinasi in general appearance but is unique in the length of the hypostomal seta h3 (>58 μm), which is 3 times as long as the gnathosomal seta, and its tip reaching or over-reaching the gnathosomal setal bases; dorsal seta j2 is very long (>70 μm), almost reaching the point of j3.

  18. Ectoparasite occurrence associated with males and females of wild rodents Oligoryzomys flavescens (Waterhouse) and Akodon azarae (Fischer) (Rodentia: Cricetidae: Sigmodontinae) in the Punta Lara wetlands, Argentina.

    PubMed

    Lareschi, Marcela

    2010-01-01

    The objective of this research was to study infestation parameters and indexes of ectoparasites associated with each sex of the wild rodents Oligoryzomys flavescens (Waterhouse) andAkodon azarae (Fischer) in the Punta Lara wetlands, Argentina. A trend towards higher mean abundance (MA) and ectoparasite specific richness was observed in males of O. flavescens whereas those values were similar for both A. azarae sexes. The prevalence of the following ectoparasites was significantly higher on males (P<0.05): Mysolaelaps microspinosus Fonseca (65.2%) and Hoplopleura travassosi Werneck (73.9%) on O. flavescens, and Ixodes loricatus Neumann (71.4%) on A. azarae. Only H. travassosi mean abundance was significantly higher on males (MA=44.1). Since I. loricatus and Hoplopleura spp. are involved in the transmission of pathogens that cause diseases in animals and humans, and whose reservoirs are rodent hosts, these results are epidemiologically important.

  19. Morphometric analysis of the placenta in the New World mouse Necromys lasiurus (Rodentia, Cricetidae): a comparison of placental development in cricetids and murids

    PubMed Central

    2013-01-01

    Background Stereology is an established method to extrapolate three-dimensional quantities from two-dimensional images. It was applied to placentation in the mouse, but not yet for other rodents. Herein, we provide the first study on quantitative placental development in a sigmodontine rodent species with relatively similar gestational time. Placental structure was also compared to the mouse, in order to evaluate similarities and differences in developmental patterns at the end of gestation. Methods Fetal and placental tissues of Necromys lasiurus were collected and weighed at 3 different stages of gestation (early, mid and late gestation) for placental stereology. The total and relative volumes of placenta and of its main layers were investigated. Volume fractions of labyrinth components were quantified by the One Stop method in 31 placentae collected from different individuals, using the Mercator® software. Data generated at the end of gestation from N. lasiurus placentae were compared to those of Mus musculus domesticus obtained at the same stage. Results A significant increase in the total absolute volumes of the placenta and its main layers occurred from early to mid-gestation, followed by a reduction near term, with the labyrinth layer becoming the most prominent area. Moreover, at the end of gestation, the total volume of the mouse placenta was significantly increased compared to that of N. lasiurus although the proportions of the labyrinth layer and junctional zones were similar. Analysis of the volume fractions of the components in the labyrinth indicated a significant increase in fetal vessels and sinusoidal giant cells, a decrease in labyrinthine trophoblast whereas the proportion of maternal blood space remained stable in the course of gestation. On the other hand, in the mouse, volume fractions of fetal vessels and sinusoidal giant cells decreased whereas the volume fraction of labyrinthine trophoblast increased compared to N. lasiurus placenta. Conclusions Placental development differed between N. lasiurus and M. musculus domesticus. In particular, the low placental efficiency in N. lasiurus seemed to induce morphological optimization of fetomaternal exchanges. In conclusion, despite similar structural aspects of placentation in these species, the quantitative dynamics showed important differences. PMID:23433040

  20. Climatic niche conservatism and ecological opportunity in the explosive radiation of arvicoline rodents (Arvicolinae, Cricetidae).

    PubMed

    Lv, Xue; Xia, Lin; Ge, Deyan; Wu, Yongjie; Yang, Qisen

    2016-05-01

    Climatic niche conservatism shapes patterns of diversity in many taxonomic groups, while ecological opportunity (EO) can trigger rapid speciation that is less constrained by the amount of time a lineage has occupied a given habitat. These two processes are well studied, but limited research has considered their joint and relative roles in shaping diversity patterns. We characterized climatic and biogeographic variables for 102 species of arvicoline rodents (Arvicolinae, Cricetidae), testing the effects of climatic niche conservatism and EO on arvicoline diversification as lineages transitioned between biogeographic regions. We found that the amount of time a lineage has occupied a precipitation niche is positively correlated with diversity along a precipitation gradient, suggesting climatic niche conservatism. In contrast, shift in diversification rate explained diversity patterns along a temperature gradient. Our results suggest that an indirect relationship exists between temperature and diversification that is associated with EO as arvicoline rodents colonized warm Palearctic environments. Climatic niche conservatism alone did not fully explain diversity patterns under density-dependence, highlighting the additional importance of EO-related processes in promoting the explosive radiation in arvicoline rodents and shaping diversity pattern among biogeographic regions and along climatic gradients.

  1. Epizootiology of Tacaribe Serocomplex Viruses (Arenaviridae) Associated with Neotomine Rodents (Cricetidae, Neotominae) in Southern California

    PubMed Central

    Milazzo, Mary Louise; Cajimat, Maria N. B.; Mauldin, Matthew R.; Bennett, Stephen G.; Hess, Barry D.; Rood, Michael P.; Conlan, Christopher A.; Nguyen, Kiet; Wekesa, J. Wakoli; Ramos, Ronald D.; Bradley, Robert D.

    2015-01-01

    Abstract The objective of this study was to advance our knowledge of the epizootiology of Bear Canyon virus and other Tacaribe serocomplex viruses (Arenaviridae) associated with wild rodents in California. Antibody (immunoglobulin G [IgG]) to a Tacaribe serocomplex virus was found in 145 (3.6%) of 3977 neotomine rodents (Cricetidae: Neotominae) captured in six counties in southern California. The majority (122 or 84.1%) of the 145 antibody-positive rodents were big-eared woodrats (Neotoma macrotis) or California mice (Peromyscus californicus). The 23 other antibody-positive rodents included a white-throated woodrat (N. albigula), desert woodrat (N. lepida), Bryant's woodrats (N. bryanti), brush mice (P. boylii), cactus mice (P. eremicus), and deer mice (P. maniculatus). Analyses of viral nucleocapsid protein gene sequence data indicated that Bear Canyon virus is associated with N. macrotis and/or P. californicus in Santa Barbara County, Los Angeles County, Orange County, and western Riverside County. Together, analyses of field data and antibody prevalence data indicated that N. macrotis is the principal host of Bear Canyon virus. Last, the analyses of viral nucleocapsid protein gene sequence data suggested that the Tacaribe serocomplex virus associated with N. albigula and N. lepida in eastern Riverside County represents a novel species (tentatively named “Palo Verde virus”) in the genus Arenavirus. PMID:25700047

  2. Complete mitochondrial genome sequence of Marmota himalayana (Rodentia: Sciuridae) and phylogenetic analysis within Rodentia.

    PubMed

    Chao, Q J; Li, Y D; Geng, X X; Zhang, L; Dai, X; Zhang, X; Li, J; Zhang, H J

    2014-04-14

    This is the first report of a complete mitochondrial genome sequence from Himalayan marmot (Marmota himalayana, class Marmota). We determined the M. himalayana mitochondrial (mt) genome sequence by using long-PCR methods and a primer-walking sequencing strategy with genus-specific primers. The complete mt genome of M. himalayana was 16,443 bp in length and comprised 13 protein-coding genes, 2 ribosomal RNA (rRNA) genes, 22 transfer RNA (tRNA) genes, and a typical control region (CR). Gene order and orientation were identical to those in mt genomes of most vertebrates. The heavy strand showed an overall A+T content of 63.49%. AT and GC skews for the mt genome of the M. himalayana were 0.012 and -0.300, respectively, indicating a nucleotide bias against T and G. The control region was 997 bp in size and displayed some unusual features, including absence of repeated motifs and two conserved sequence blocks (CSB2 and CSB3), which is consistent with observations from two other rodent species, Sciurus vulgaris and Myoxus glis. Phylogenetic analysis of complete mt DNA sequences without the control region including 30 taxa of Rodentia was performed with Maximum-Likelihood (ML) and Bayesian Inference (BI) methods and provided strong support for Sciurognathi polyphyly and Hystricognathi monophyly. This analysis also provided evidence that M. himalayana mt DNA was closely related to that from Sciurus vulgaris (Sciuridae) and was similar to mt DNA from Myoxus glis.

  3. Acariform mites (Acariformes) - permanent symbionts of Hapalomysdelacouri Thomas (Rodentia, Muridae) in Vietnam.

    PubMed

    Bochkov, Andre V; Abramov, Alexei V

    2014-01-01

    Two new species of parasitic acariform mites (Acariformes) are described from the Delacour's marmoset rat Hapalomysdelacouri Thomas (Rodentia: Muridae) in Vietnam: Afrolistrophorus (Afrolistrophorus) hapalomyssp. n. (Listrophoridae) and Radfordia (Radfordia) mirabilissp. n. (Myobiidae). Based on morphological evidences, we show that species of both mite genera associated with Hapalomys Blyth do not demonstrate clear phylogenetic links with respective congeners from rodents of the closest genus Chiropodomys Peters (Rodentia: Muridae).

  4. Arthropod symbiotes of Laonastes aenigmamus (Rodentia:Diatomyidae).

    PubMed

    Bochkov, A V; Abramov, A V; Durden, L A; Apanaskevich, D A; Stekolnikov, A A; Stanyukovich, M K; Gnophanxay, S; Tikhonov, A N

    2011-04-01

    Arthropod symbiotes of the Laotian rock-rat, Laonastes aenigmamus (Rodentia:Diatomyidae), from Laos are examined. This host is a member of Diatomyidae previously thought to have gone extinct >10 million yr ago. Permanent symbiotes are represented by 2 species, a new species of sucking louse, Polyplax sp., near rhizomydis (Phthiraptera:Polyplacidae), and a new species of fur mite, Afrolistrophorus sp., near maculatus (Acariformes:Listrophoridae). The temporary parasites are represented by 18 species, i.e., 1 mesostigmatan species, i.e., a new species of Androlaelaps near casalis (Parasitiformes:Laelapidae); immature stages of 2 tick species, Ixodes granulatus and Haemaphysalis sp. (Parasitiformes:Ixodidae); and a rich fauna of chiggers (Acariformes:Trombiculidae) comprising 8 genera and 15 species. It is hypothesized that this host completely lost its initial fauna of ectosymbiotes and that ancestors of the recorded symbiotes switched to this host from rodents of the superfamily Muroidea.

  5. Taxonomic position of Eothenomys wardi (Arvicolinae: Cricetidae) based on morphological and molecular analyses with a detailed description of the species.

    PubMed

    Zeng, Tao; Jin, Wei; Sun, Zhi Yu; Liu, Yang; Murphy, Robert W; Fu, Jian Rong; Wang, Xin; Hou, Quan Fen; Tu, Fei Yun; Liao, Rui; Liu, Shao Ying; Yue, Bi Song

    2013-01-01

    Ward's Red-backed Vole (Eothenomys wardi) is a rodent from the family Cricetidae. This endemic species occurs only in extreme northwestern Yunnan province, China in the Mekong and Salween river divide. It occupies steep cliffs at 2,800 to 4,250 m above sea level on the remote Qinghai-Tibetan plateau. The validity of E. wardi is controversial and no specimens exist apart from the nominal series. In 2010, we collected 38 topotypes of E. wardi from Meri Snow Mountain. The results of our phylogenetic analyses based on nucleotide sequences of the mitochondrial genes cytochrome b (cytb) and cytochrome c oxidase subunit one (COI) suggest that E. wardi is the sister group of E. custos, against its previously presumed sister species or conspecific species E. chinensis. In addition, seven out of 34 morphological characters differentiate E. wardi from other members of the genus Eothenomys. Therefore, we consider E. wardi to be a valid species and we provide its detailed morphological description.

  6. Environmental Compliance Assessment and Management System Program (ECAMP). U.S. Air Force European Economic Community (EEC)

    DTIC Science & Technology

    1993-09-01

    pipistrellus RODENTIA Sciuridae Citellus citellus Cricetidae Cricetus cricetus Hystricidae Hystrix crisata CARNIVORA Canidae Canis lupus Alopex lagopus...cabrerae Microtus oeconomus arenicola Zapodidae Sicista betulina Hystricidae Hystrix cristata CARNIVORA Canidae Canis lupus except Spanish populations

  7. New karyotypes of Atlantic tree rats, genus Phyllomys (Rodentia: Echimyidae).

    PubMed

    Araújo, Naiara Pereira; Loss, Ana Carolina; Cordeiro-Junior, Dirceu A; da Silva, Kátia Regina; Leite, Yuri L R; Svartman, Marta

    2014-01-01

    Phyllomys (Echimyidae, Rodentia) is a genus of Neotropical rodents with available cytogenetic data restricted to six out of 13 species, mainly based on simple staining methods, without detailed analyses. In this work, we present new karyotypes for Phyllomys lamarum (diploid number 2n = 56, fundamental number or number of autosomal arms FN = 102) and Phyllomys sp. (2n = 74, FN = 140) from the state of Minas Gerais, southeastern Brazil. We provide the first GTG- and CBG-banding patterns, silver-staining of the nucleolar organizer regions (Ag-NORs), and fluorescence in situ hybridization (FISH) with telomeric and 45S rDNA probes of Phyllomys. In addition to examining their chromosomes and phenotypic characters, we sequenced mitochondrial DNA from the specimens analyzed to confirm their taxonomic identification. The comparison of the distinctive chromosome complements of our specimens with those of other species of Phyllomys already published allowed us to conclude that chromosome data may be very useful for the taxonomy of the genus, as no two species analyzed presented the same diploid and fundamental numbers (2n and FN).

  8. A Transitional Gundi (Rodentia: Ctenodactylidae) from the Miocene of Israel.

    PubMed

    López-Antoñanzas, Raquel; Gutkin, Vitaly; Rabinovich, Rivka; Calvo, Ran; Grossman, Aryeh

    2016-01-01

    We describe a new species of gundi (Rodentia: Ctenodactylidae: Ctenodactylinae), Sayimys negevensis, on the basis of cheek teeth from the Early Miocene of the Rotem Basin, southern Israel. The Rotem ctenodactylid differs from all known ctenodactylid species, including Sayimys intermedius, which was first described from the Middle Miocene of Saudi Arabia. Instead, it most resembles Sayimys baskini from the Early Miocene of Pakistan in characters of the m1-2 (e.g., the mesoflexid shorter than the metaflexid, the obliquely orientated hypolophid, and the presence of a strong posterolabial ledge) and the upper molars (e.g., the paraflexus that is longer than the metaflexus). However, morphological (e.g., presence of a well-developed paraflexus on unworn upper molars) and dimensional (regarding, in particular, the DP4 and M1 or M2) differences between the Rotem gundi and Sayimys baskini distinguish them and testify to the novelty and endemicity of the former. In its dental morphology, Sayimys negevensis sp. nov. shows a combination of both the ultimate apparition of key-characters and incipient features that would be maintained and strengthened in latter ctenodactylines. Thus, it is a pivotal species that bridges the gap between an array of primitive ctenodactylines and the most derived, Early Miocene and later, gundis.

  9. A Transitional Gundi (Rodentia: Ctenodactylidae) from the Miocene of Israel

    PubMed Central

    López-Antoñanzas, Raquel; Gutkin, Vitaly; Rabinovich, Rivka; Calvo, Ran; Grossman, Aryeh

    2016-01-01

    We describe a new species of gundi (Rodentia: Ctenodactylidae: Ctenodactylinae), Sayimys negevensis, on the basis of cheek teeth from the Early Miocene of the Rotem Basin, southern Israel. The Rotem ctenodactylid differs from all known ctenodactylid species, including Sayimys intermedius, which was first described from the Middle Miocene of Saudi Arabia. Instead, it most resembles Sayimys baskini from the Early Miocene of Pakistan in characters of the m1-2 (e.g., the mesoflexid shorter than the metaflexid, the obliquely orientated hypolophid, and the presence of a strong posterolabial ledge) and the upper molars (e.g., the paraflexus that is longer than the metaflexus). However, morphological (e.g., presence of a well-developed paraflexus on unworn upper molars) and dimensional (regarding, in particular, the DP4 and M1 or M2) differences between the Rotem gundi and Sayimys baskini distinguish them and testify to the novelty and endemicity of the former. In its dental morphology, Sayimys negevensis sp. nov. shows a combination of both the ultimate apparition of key-characters and incipient features that would be maintained and strengthened in latter ctenodactylines. Thus, it is a pivotal species that bridges the gap between an array of primitive ctenodactylines and the most derived, Early Miocene and later, gundis. PMID:27049960

  10. Hymenolepis folkertsi n. sp. (Eucestoda: Hymenolepididae) in the oldfield mouse Peromyscus polionotus (Wagner) (Rodentia: Cricetidae: Neotominae) from the southeastern Nearctic with comments on tapeworm faunal diversity among deer mice.

    PubMed

    Makarikov, Arseny A; Nims, Todd N; Galbreath, Kurt E; Hoberg, Eric P

    2015-06-01

    A previously unrecognized species of hymenolepidid cestode attributable to Hymenolepis is described based on specimens in Peromyscus polionotus, oldfield mouse, from Georgia near the southeastern coast of continental North America. Specimens of Hymenolepis folkertsi n. sp. differ from those attributed to most other species in the genus by having testes arranged in a triangle and a scolex with a prominent rostrum-like protrusion. The newly recognized species is further distinguished by the relative position and length of the cirrus sac, shape of seminal receptacle, and relative size of external seminal vesicle and seminal receptacle. Hymenolepidid cestodes have sporadically been reported among the highly diverse assemblage of Peromyscus which includes 56 distinct species in the Nearctic. Although the host genus has a great temporal duration and is endemic to the Nearctic, current evidence suggests that tapeworm faunal diversity reflects relatively recent assembly through bouts of host switching among other cricetid, murid, and geomyid rodents in sympatry.

  11. Mazzanema n. gen. and Mazzanema fortuita n. comb. for Longistriata fortuita Freitas, Lent, and Almeida, 1937 (Nematoda: Heligmonellidae), a parasite of the marsh rat Holochilus chacarius (Rodentia: Cricetidae) from northern Argentina.

    PubMed

    Digiani, María Celina; Notarnicola, Juliana; Paulos, María Soledad

    2013-10-01

    The species described as Longistriata fortuita Freitas, Lent, and Almeida, 1937 is here redescribed from new material collected from the type host, Holochilus chacarius balnearum Thomas, and the type locality, San Martín del Tabacal, Salta, Argentina. Neotypes are designed for the species since the type material deposited by the authors is lost. The original description did not include the synlophe or the female and both are here described. Several characters of the synlophe as the number of ridges (14-19), the ridges continuous and all around body, and the presence of a gradient of size of the ridges allow us to place the species within the Heligmonellidae, Nippostrongylinae. The species possesses a unique combination of characters as the synlophe having a carene together with characters of the caudal bursa as the pattern 1-3-1 and the strong development of the dorsal lobe and ray, which precludes its inclusion in any known genus of Nippostrongylinae. A new genus Mazzanema n. gen. is proposed for it, resulting in the new combination Mazzzanema fortuita n. comb.

  12. Karyotypes of two rare rodents, Hapalomys delacouri and Typhlomys cinereus (Mammalia, Rodentia), from Vietnam.

    PubMed

    Abramov, Alexei V; Aniskin, Vladimir M; Rozhnov, Viatcheslav V

    2012-01-01

    Karyotypes of Hapalomys delacouri (Rodentia, Muridae) and Typhlomys cinereus (Rodentia, Platacanthomyidae) from Vietnam are described for the first time. The diploid karyotype of Hapalomys delacouri is 38 (NFa=48), consisting of six pairs of bi-armed and 12 pairs of acrocentric autosomes decreasing in size; plus a large metacentric X chromosome and Y chromosome, also metacentric, that is equal in size to the largest pair of acrocentric autosomes. The newly described karyotype differs significantly from that reported for Hapalomys delacouri from northern Thailand. The latter record very likely represents a different species of Hapalomys, possibly the taxon Hapalomys pasquieri described from north-central Laos.The diploid karyotype of Typhlomys cinereus is 38 (NF=48), consisting of five pairs of meta- to submetacentric and 14 pairs of acrocentric chromosomes varying in size from large to small; sex chromosomes were not defined.

  13. Identification of lymphocytic choriomeningitis mammarenavirus in house mouse (Mus musculus, Rodentia) in French Guiana.

    PubMed

    Lavergne, Anne; de Thoisy, Benoît; Tirera, Sourakhata; Donato, Damien; Bouchier, Christiane; Catzeflis, François; Lacoste, Vincent

    2016-01-01

    Thirty-seven house mice (Mus musculus, Rodentia) caught in different localities in French Guiana were screened to investigate the presence of lymphocytic choriomeningitis mammarenavirus (LCMV). Two animals trapped in an urban area were found positive, hosting a new strain of LCMV, that we tentatively named LCMV "Comou". The complete sequence was determined using a metagenomic approach. Phylogenetic analyses revealed that this strain is related to genetic lineage I composed of strains inducing severe disease in humans. These results emphasize the need for active surveillance in humans as well as in house mouse populations, which is a rather common rodent in French Guianese cities and settlements.

  14. A new species of Reithrodontomys, subgenus Aporodon (Cricetidae: Neotominae), from the highlands of Costa Rica, with comments on Costa Rican and Panamanian Reithrodontomys

    USGS Publications Warehouse

    Gardner, Alfred L.; Carleton, Michael D.

    2009-01-01

    A new species of the rodent genus Reithrodontomys (Cricetidae: Neotominae) is described from Cerro Asuncion in the western Cordillera de Talamanca, Costa Rica. The long tail, elongate rostrum, bulbous braincase, and complex molars of the new species associate it with members of the subgenus Aporodon, tenuirostris species group. In its diminutive size and aspects of cranial shape, the new species (Reithrodontomys musseri, sp. nov.) most closely resembles R. microdon, a form known from highlands in Guatemala and Chiapas, Mexico. In the course of differentially diagnosing the new species, we necessarily reviewed the Costa Rican and Panamanian subspecies of R. mexicanus based on morphological comparisons, study of paratypes and vouchers used in recent molecular studies, and morphometric analyses. We recognize Reithrodontomys cherrii (Allen, 1891) and R. garichensis finders and Pearson, 1940, as valid species, and allocate R. mexicanus potrerograndei Goodwin, 1945, as a subjective synonym of R. brevirostris Goodwin, 1943. Critical review of museum specimens collected subsequent to Hooper's (1952) revision is needed and would do much to improve understanding of Reithrodontomys taxonomy and distribution in Middle America.

  15. The size of sebaceous glands in relation to the size of hair follicles on the heads of some small mammals (Insectivora, Chiroptera, Rodentia).

    PubMed

    Haffner, M

    1998-04-01

    Many large sebaceous glands have been described, and functions such as scent production suggested, but gland size has seldom been studied in relation to the surface area of their hair follicles. However, investigating this relationship is essential for establishing whether glands produce more sebum than would be required for lubricating associated hair alone. Here, the relationship between sebaceous gland size and the surface area of the associated hair follicles has been studied. Glands on the heads of 20 species from three orders were compared with those associated with fur hairs. In all species, the fur hairs had small hair follicles with small sebaceous glands, as had the mystacial and submandibular hairs of Rodentia. Medium-sized glands and hairs were found in the mystacial and submandibular region in Insectivora, and in the circumoral region in Chiroptera and Rodentia. Large glands and hairs were found on a pad in the corner of the mouth in Rodentia. Although the size of glands was not directly proportional to hair size, some gross trends were noted. Vibrissae had either no or very small sebaceous glands. It is likely that sebum has to be provided from elsewhere to lubricate their surfaces. The glands on the snout of Insectivora and Chiroptera are clearly enlarged and could probably produce more sebum than would be required for grooming vibrissae alone. In Rodentia, vibrissae were surrounded by small hair and glands, and the nearest glands large enough to provide sebum were the glands on the pad in the mouth corner.

  16. Broadening diversity in the Arostrilepis horrida complex: Arostrilepis kontrimavichusi n. sp. (Cyclophyllidea: Hymenolepididae) in the western red-backed vole Myodes californicus (Merriam) (Cricetidae: Arvicolinae) from temperate latitudes of the Pacific Northwest, North America.

    PubMed

    Makarikov, Arseny A; Hoberg, Eric P

    2016-06-01

    Specimens originally identified provisionally as Hymenolepis horrida (Linstow, 1901) [later Arostrilepis horrida (Linstow, 1901)] in Myodes californicus (Merriam) from near the Pacific coastal zone of southern Oregon are revised. Specimens in western red-backed voles represent an undescribed species of Arostrilepis Mas Coma & Tenora, 1997, contributing to recognition and resolution of a broadening complex encompassing cryptic diversity for these hymenolepidid tapeworms distributed across the Holarctic region. Consistent with recent studies defining diversity in the genus, the form, dimensions, and spination (pattern, shape and size) of the cirrus are diagnostic. Among 12 nominal congeners, specimens of A. kontrimavichusi n. sp. are further distinguished by the relative position and length of the cirrus-sac, arrangement of the testes and relative size of the external seminal vesicle and seminal receptacle. Specimens from Oregon voles represent the fifth endemic hymenolepidid in this genus from the Nearctic. Host range for the North American assemblage of species includes Cricetidae (Arvicolinae and Neotominae), Heteromyidae, Geomyidae, and rarely Sciuridae.

  17. A new species, Litomosoides odilae n. sp (Nematoda: Onchocercidae) from Oligoryzomys nigripes (Rodentia: Muridae) in the rainforest of Misiones, Argentina.

    PubMed

    Notarnicola, Juliana; Navone, Graciela

    2002-10-01

    A new species of Litomosoides was collected from the abdominal cavity of Oligoryzomys nigripes (Rodentia: Muridae) in a semideciduous secondary rainforest of Misiones, Argentina. Litomosoides odilae n. sp. belongs to the carinii group and is characterized by the amphids displaced dorsally; buccal capsule with an anterior segment transparent and an annular asymmetrical thickening; esophagus divided, with the posterior glandular portion slightly wider than the muscular; male cloacal aperture strongly protruded; and microfilaria sheathed with an attenuated tail. The morphology of the new species, which is similar to that of L petteri, a parasite of marsupials in Brazil, suggests that host-switching events may have occurred in the diversification of this genus.

  18. A new genus and species of Heligmonellidae (Nematoda: Trichostrongylina) parasitic in Delomys dorsalis (Rodentia: Sigmodontinae) from Misiones, Argentina.

    PubMed

    Digiani, María Celina; Kinsella, John M

    2014-10-01

    Alippistrongylus bicaudatus gen. et sp. n. (Nematoda: Heligmonellidae) is described from the striped Atlantic forest rat, Delomys dorsalis (Hensel) (Rodentia: Sigmodontinae), from the province of Misiones in Argentina. The new genus and species is characterised by a synlophe of 21 unequal ridges in both sexes without a gradient in size, with two ridges weakly sclerotised and oriented perpendicularly in the dorsal left quadrant; males with a highly dissymmetrical bursa with a hypertrophied right lobe, and females with a dorsal conical appendage just posterior to the vulva, conferring a two-tailed appearance to the female worms.

  19. The complete mitochondrial genome of Microtus fortis calamorum (Arvicolinae, Rodentia) and its phylogenetic analysis.

    PubMed

    Jiang, Xianhuan; Gao, Jun; Ni, Liju; Hu, Jianhua; Li, Kai; Sun, Fengping; Xie, Jianyun; Bo, Xiong; Gao, Chen; Xiao, Junhua; Zhou, Yuxun

    2012-05-01

    Microtus fortis is a special resource of rodent in China. It is a promising experimental animal model for the study on the mechanism of Schistosome japonicum resistance. The first complete mitochondrial genome sequence for Microtus fortis calamorum, a subspecies of M. fortis (Arvicolinae, Rodentia), was reported in this study. The mitochondrial genome sequence of M. f. calamorum (Genbank: JF261175) showed a typical vertebrate pattern with 13 protein coding genes, 2 ribosomal RNAs, 22 transfer RNAs and one major noncoding region (CR region).The extended termination associated sequences (ETAS-1 and ETAS-2) and conserved sequence block 1 (CSB-1) were found in the CR region. The putative origin of replication for the light strand (O(L)) of M. f. calamorum was 35bp long and showed high conservation in stem and adjacent sequences, but the difference existed in the loop region among three species of genus Microtus. In order to investigate the phylogenetic position of M. f. calamorum, the phylogenetic trees (Maximum likelihood and Bayesian methods) were constructed based on 12 protein-coding genes (except for ND6 gene) on H strand from 16 rodent species. M. f. calamorum was classified into genus Microtus, Arvcicolinae for the highly phylogenetic relationship with Microtus kikuchii (Taiwan vole). Further phylogenetic analysis results based on the cytochrome b gene ranged from M. f. calamorum to one of the subspecies of M. fortis, which formed a sister group of Microtus middendorfii in the genus Microtus.

  20. Paternal behavior and testosterone plasma levels in the Volcano Mouse Neotomodon alstoni (Rodentia: Muridae).

    PubMed

    Luis, Juana; Ramírez, Lorena; Carmona, Agustín; Ortiz, Guadalupe; Delgado, Jesús; Cárdenas, René

    2009-01-01

    Paternal behavior and testosterone plasma levels in the Volcano Mouse Neotomodon alstoni (Rodentia: Muridae). Although initially it was thought that testosterone inhibited the display of paternal behavior in males of rodents, it has been shown that in some species high testosterone levels are needed for exhibition of paternal care. In captivity, males of Volcano Mouse (Neotomodon alstoni) provide pups the same care provided by the mother, with the exception of suckling. Here we measured plasmatic testosterone concentrations 10 days after mating, five and 20 days postpartum, and 10 days after males were isolated from their families in order to determine possible changes in this hormone, associated to the presence and age of pups. Males of Volcano Mouse exhibited paternal behavior when their testosterone levels were relatively high. Although levels of this hormone did not change with the presence or pups age, males that invested more time in huddling showed higher testosterone levels. It is possible that in the Volcano Mouse testosterone modulates paternal behavior indirectly, as in the California mouse.

  1. Description of the karyotype of Rhagomys rufescens Thomas, 1886 (Rodentia, Sigmodontinae) from Southern Brazil Atlantic forest

    PubMed Central

    2010-01-01

    Rhagomys rufescens (Rodentia: Sigmodontinae) is an endemic species of the Atlantic forest from Southern and Southeastern Brazil. Some authors consider Rhagomys as part of the tribe Thomasomyini; but its phylogenetic relationships remain unclear. Chromosomal studies on eight specimens of Rhagomys rufescens revealed a diploid number of 2n = 36 and a number of autosome arms FN = 50. GTG, CBG and Ag-NOR banding and CMA3 /DAPI staining were performed on metaphase chromosomes. Eight biarmed and nine acrocentric pairs were found in the karyotype of this species. The X and Y chromosomes were both acrocentric. Most of the autosomes and the sex chromosomes showed positive C-bands in the pericentromeric region. The X chromosome showed an additional heterochromatic block in the proximal region of the long arm. Nucleolus organizer regions (NORs) were located in the pericentromeric region of three biarmed autosomes (pairs 4, 6 and 8) and in the telomeric region of the short arm of three acrocentrics (pairs 10, 12 and 17). CMA 3 /DAPI staining produced fluorescent signals in many autosomes, especially in pairs 4, 6, and 8. This study presents cytogenetic data of Rhagomys rufescens for the first time. PMID:21637420

  2. Codivergence in heteromyid rodents (Rodentia: heteromyidae) and their sucking lice of the genus Fahrenholzia (Phthiraptera: anoplura).

    PubMed

    Light, Jessica E; Hafner, Mark S

    2008-06-01

    Although most studies of codivergence rely primarily on topological comparisons of host and parasite phylogenies, temporal assessments are necessary to determine if divergence events in host and parasite trees occurred contemporaneously. A combination of cophylogenetic analyses and comparisons of branch lengths are used in this study to understand the host-parasite association between heteromyid rodents (Rodentia: Heteromyidae) and their sucking lice of the genus Fahrenholzia (Phthiraptera: Anoplura). Cophylogenetic comparisons based on nucleotide substitutions in the mitochondrial COI gene reveal a significant, but not perfect, pattern of cophylogeny between heteromyids and their sucking lice. Regression analyses show a significant functional relationship between the lengths of analogous branches in the host and parasite trees, indicating that divergence events in hosts and parasites were approximately contemporaneous. Thus, the topological similarity observed between heteromyids and their lice is the result of codivergence. These analyses also show that the COI gene in lice is evolving two to three times faster than the same gene in their hosts (similar to the results of studies of other lice and their vertebrate hosts) and that divergence events in lice occurred shortly after host divergence. We recommend that future studies of codivergence include temporal comparisons and, when possible, use the same molecular marker(s) in hosts and parasites to achieve the greatest insight into the history of the host-parasite relationship.

  3. Helminth fauna of the Siberian chipmunk, Tamias sibiricus Laxmann (Rodentia, Sciuridae) introduced in suburban French forests.

    PubMed

    Pisanu, Benoît; Jerusalem, Christelle; Huchery, Cindy; Marmet, Julie; Chapuis, Jean-Louis

    2007-05-01

    The spread of an immigrant host species can be influenced both by its specific helminth parasites that come along with it and by newly acquired infections from native fauna. The Siberian chipmunk, Tamias sibiricus Laxmann (Rodentia, Sciuridae), a northeastern Eurasiatic ground nesting Sciurid, has been introduced in France for less than three decades. Thirty individuals were collected from three suburban forests in the Ile-de-France Region between 2002 and 2006. Two intestinal nematode species dominated the helminth fauna: Brevistriata skrjabini [Prevalence, P, 99% C.I., 87% (64-97%); mean intensity, M.I., 99% C.I., 43 (28-78)] and Aonchotheca annulosa [P, 47% (25-69%); M.I., 35 (3-157)]. B. skrjabini is a direct life cycle nematode species of North Eurasiatic origin, with a restricted spectrum of phylogenetically related suitable hosts. This result indicates that B. skrjabini successfully settled and spread with founder pet chipmunks maintained in captivity and released in natura. Chipmunks acquired A. annulosa, a nematode species with a large spectrum of phylogenetically unrelated suitable host species, from local Muroid rodent species with similar behavior, life-history traits and habitats. Quantitative studies are needed to evaluate the potential for both B. skrjabini and A. annulosa to impede the spread of Tamias and for B. skrjabini to favor chipmunk colonization through detrimental effects upon native co-inhabiting host species.

  4. A new species of porcupine, genus Coendou (Rodentia: Erethizontidae) from the Atlantic forest of northeastern Brazil.

    PubMed

    Pontes, Antonio Rossano Mendes; Gadelha, José Ramon; Melo, Éverton R A; de Sá, Fabrício Bezerra; Loss, Ana Carolina; Caldara Junior, Vilacio; Costa, Leonora Pires; Leite, Yuri L R

    2013-01-01

    We report the discovery of a new species of Coendou (Rodentia, Erethizontidae), here designated Coendou speratus sp. nov. This small porcupine, locally known as coandumirim, is found in the Pernambuco Endemism Centre in the Atlantic coast of northeastern Brazil north of the São Francisco river, one of the most important known biodiversity hotspots. The geographic range of C. speratus overlaps with that of the larger, widespread C. prehensilis, but not with that of C. insidiosus from the southeastern Atlantic forest, nor with that of C. nycthemera, an eastern Amazonian species. Coendou speratus is a small-bodied, long-tailed species that appears to be completely spiny because it lacks long dorsal fur. The dorsal quills have conspicuously brownish red tips that contrast with the blackish dorsal background color. The new species is overall similar to C. nycthemera, but the dorsal body quills are typically tricolored in the former and bicolored in the latter. The new species is externally very distinct from C. insidiosus, especially because the latter has bicolored dorsal quills that are almost completely hidden beneath longer and homogeneous pale or dark hairs.

  5. DNA extraction from bristles and quills of Chaetomys subspinosus (Rodentia: Erethizontidae) using a novel protocol.

    PubMed

    Oliveira, C G; Martinez, R A; Gaiotto, F A

    2007-09-30

    DNA extraction protocols are as varied as DNA sources. When it comes to endangered species, it is especially important to pay attention to all details that ensure the completion of the study goals and effectiveness in attaining useful data for conservation. Chaetomys subspinosus (Rodentia: Erethizontidae) is a secretive arboreal porcupine endemic to certain ecosystems of the Brazilian Atlantic Forest. A multidisciplinary study (including genetic data) was performed to create a management plan for the conservation of this species. Individuals from natural populations of the states of Bahia, Espírito Santo and Sergipe were sampled. To obtain a reliable and abundant amount of starting material, non-destructive methods were tested, extracting DNA from the bristles and quills that comprise most of this animal's hide. This method has also been innovative in adapting a DNA extraction protocol traditionally used for plants. Digestion using proteinase K was followed by protein precipitation with CTAB, a chloroform-isoamyl alcohol cleaning and DNA precipitation with isopropyl alcohol. This protocol supplies good-quality DNA for genetic analysis with molecular markers based on PCR.

  6. Postnatal ontogeny of limb proportions and functional indices in the subterranean rodent Ctenomys talarum (Rodentia: Ctenomyidae).

    PubMed

    Echeverría, Alejandra Isabel; Becerra, Federico; Vassallo, Aldo Iván

    2014-08-01

    Burrow construction in the subterranean Ctenomys talarum (Rodentia: Ctenomyidae) primarily occurs by scratch-digging. In this study, we compared the limbs of an ontogenetic series of C. talarum to identify variation in bony elements related to fossorial habits using a morphometrical and biomechanical approach. Diameters and functional lengths of long bones were measured and 10 functional indices were constructed. We found that limb proportions of C. talarum undergo significant changes throughout postnatal ontogeny, and no significant differences between sexes were observed. Five of six forelimb indices and two of four hindlimb indices showed differences between ages. According to discriminant analysis, the indices that contributed most to discrimination among age groups were robustness of the humerus and ulna, relative epicondylar width, crural and brachial indices, and index of fossorial ability (IFA). Particularly, pups could be differentiated from juveniles and adults by more robust humeri and ulnae, wider epicondyles, longer middle limb elements, and a proportionally shorter olecranon. Greater robustness indicated a possible compensation for lower bone stiffness while wider epicondyles may be associated to improved effective forces in those muscles that originate onto them, compensating the lower muscular development. The gradual increase in the IFA suggested a gradual enhancement in the scratch-digging performance due to an improvement in the mechanical advantage of forearm extensors. Middle limb indices were higher in pups than in juveniles-adults, reflecting relatively more gracile limbs in their middle segments, which is in accordance with their incipient fossorial ability. In sum, our results show that in C. talarum some scratch-digging adaptations are already present during early postnatal ontogeny, which suggests that they are prenatally shaped, and other traits develop progressively. The role of early digging behavior as a factor influencing on

  7. Redescription of Trichuris pampeana (Nematoda: Trichuridae) from the South American subterranean rodent Ctenomys talarum Thomas, 1898 (Rodentia: Octodontidae).

    PubMed

    Rossin, M Alejandra; Malizia, Ana I

    2005-02-01

    Trichuris pampeana Suriano and Navone, 1994 (Nematoda: Trichuridae) is redescribed from voucher specimens from the type host Ctenomys azarae Thomas, 1903 (Rodentia: Octodontidae) and from parasites collected from 2 populations of the subterranean rodent C. talarum Thomas, 1898 from Mar de Cobo and Necochea, Buenos Aires Province, Argentina. After a revision of these nematodes, it was confirmed that the following characters were not considered in the original description: bacillary band, cells from the esophagointestinal junction, ejaculatory duct, vas deferens, adanal papillae, vagina, oviduct, and rectum. Additional information about the spicular sheath, vulva, uteri, and ovary is provided. The morphological features given in this redescription allow to confirm the identity of T. pampeana as a valid species and also to distinguish it more clearly from other species of the genus.

  8. Squamasnema amazonica n. gen. n. sp. (Heligmonellinae): A new parasite of Proechimys roberti (Rodentia: Echimyidae) in the Brazilian Amazon.

    PubMed

    Cordeiro, Helrik da Costa; Melo, Francisco Tiago de Vasconcelos; Furtado, Adriano Penha; Giese, Elane Guerreiro; Maldonado, Arnaldo; dos Santos, Jeannie Nascimento

    2015-08-01

    A new species of nematode, Squamasnema amazonica n. gen. n. sp., is described based on specimens found parasitizing the small intestine of Proechimys roberti (Rodentia: Echimyidae) collected during a survey of the fauna of Tapirapé-Aquirí National Forest (Brazil, Eastern Brazilian Amazon). The nematodes were fixed and processed for light microscopy and scanning electron microscopy (SEM). These nematodes were classified under the family Heligmonellidae and the subfamily Heligmonellinae. Although several species in the family Heligmonellidae exhibit discontinuous ridges, Squamasnema n. gen. and Trichotravassosia are the only genera with columns of scales along their entire body, as an apomorphy of the synlophe. Squamasnema n. gen. has columns of cuticular cells along its body, except for on the left flank, and exhibits a synlophe with no size gradient or inclination and does not present chitinized structures supporting the synlophe. Therefore, due to these morphological differences of Squamasnema n. gen., the creation of a new genus was necessary.

  9. A new genus and two new species of chigger mites (Acari: Trombiculidae) from the Laotian rock-rat Laonastes aenigmamus Jenkins, Kilpatrick, Robinson & Timmins (Rodentia: Diatomyidae).

    PubMed

    Stekolnikov, Alexandr A

    2014-01-01

    A new chigger mite genus Laotrombicula n. g. and two new species, Laotrombicula khunboromi n. sp. (type-species) and L. fangumi n. sp., are described from the Laotian rock-rat Laonastes aenigmamus Jenkins, Kilpatrick, Robinson & Timmins (Rodentia: Diatomyidae). The new genus is most similar to Trombiculindus Radford, 1948 and Leptotrombidium Nagayo, Miyagawa, Mitamura & Imamura, 1916 and differs from these genera by having the scutum of subhexagonal or semicircular shape vs widely rectangular; pinnatifid dorsocentral idiosomal setae vs foliaceous in Trombiculindus and unexpanded in Leptotrombidium; and by the presence of serrated longitudinal crests in the middle part of scutum.

  10. Virtual endocasts of Eocene Paramys (Paramyinae): oldest endocranial record for Rodentia and early brain evolution in Euarchontoglires

    PubMed Central

    Amador-Mughal, Farrah

    2016-01-01

    Understanding the pattern of brain evolution in early rodents is central to reconstructing the ancestral condition for Glires, and for other members of Euarchontoglires including Primates. We describe the oldest virtual endocasts known for fossil rodents, which pertain to Paramys copei (Early Eocene) and Paramys delicatus (Middle Eocene). Both specimens of Paramys have larger olfactory bulbs and smaller paraflocculi relative to total endocranial volume than later occurring rodents, which may be primitive traits for Rodentia. The encephalization quotients (EQs) of Pa. copei and Pa. delicatus are higher than that of later occurring (Oligocene) Ischyromys typus, which contradicts the hypothesis that EQ increases through time in all mammalian orders. However, both species of Paramys have a lower relative neocortical surface area than later rodents, suggesting neocorticalization occurred through time in this Order, although to a lesser degree than in Primates. Paramys has a higher EQ but a lower neocortical ratio than any stem primate. This result contrasts with the idea that primates were always exceptional in their degree of overall encephalization and shows that relative brain size and neocortical surface area do not necessarily covary through time. As such, these data contradict assumptions made about the pattern of brain evolution in Euarchontoglires. PMID:26817776

  11. Trypanosoma (Megatrypanum) lainsoni n. sp. from Mesomys hispidus (Rodentia: Echimyidae) in Brazil: trypomastigotes described from experimentally infected laboratory mice.

    PubMed

    Naiff, Roberto Daibes; Barrett, Toby Vincent

    2013-01-01

    We report the detection, isolation and description of Trypanosoma (Megatrypanum) lainsoni n. sp. from a caviomorph rodent, Mesomys hispidus (Rodentia: Echimyidae), obtained in the Rio Negro region of the state of Amazonas, in northern Brazil. Laboratory-bred white mice (Mus musculus) and rats (Rattus rattus) were inoculated with large numbers of culture forms by intraperitoneal route, and trypomastigotes appeared in their blood 3-8 days post-inoculation. One single epimastigote was also found in Mus musculus. Similar attempts to infect Rattus norvegicus, hamsters (Mesocricetus auratus), the opossum Didelphis marsupialis, the anteater Tamandua tetradactyla and triatomine bugs were unsuccessful, following six months of observations and microscopic examinations of blood films and blood cultures. As we have found no previous record of a Trypanosoma (Megatrypanum) species naturally infecting a member of the family Echimyidae, or any other caviomorph rodent, we conclude that this is the first time such an infection has been reported. The new species is unusual in the subgenus for its infectivity to laboratory mice.

  12. Virtual endocasts of Eocene Paramys (Paramyinae): oldest endocranial record for Rodentia and early brain evolution in Euarchontoglires.

    PubMed

    Bertrand, Ornella C; Amador-Mughal, Farrah; Silcox, Mary T

    2016-01-27

    Understanding the pattern of brain evolution in early rodents is central to reconstructing the ancestral condition for Glires, and for other members of Euarchontoglires including Primates. We describe the oldest virtual endocasts known for fossil rodents, which pertain to Paramys copei (Early Eocene) and Paramys delicatus (Middle Eocene). Both specimens of Paramys have larger olfactory bulbs and smaller paraflocculi relative to total endocranial volume than later occurring rodents, which may be primitive traits for Rodentia. The encephalization quotients (EQs) of Pa. copei and Pa. delicatus are higher than that of later occurring (Oligocene) Ischyromys typus, which contradicts the hypothesis that EQ increases through time in all mammalian orders. However, both species of Paramys have a lower relative neocortical surface area than later rodents, suggesting neocorticalization occurred through time in this Order, although to a lesser degree than in Primates. Paramys has a higher EQ but a lower neocortical ratio than any stem primate. This result contrasts with the idea that primates were always exceptional in their degree of overall encephalization and shows that relative brain size and neocortical surface area do not necessarily covary through time. As such, these data contradict assumptions made about the pattern of brain evolution in Euarchontoglires.

  13. A phylogeographic study of the endemic rodent Eliurus carletoni (Rodentia: Nesomyinae) in an ecological transition zone of Northern Madagascar.

    PubMed

    Rakotoarisoa, Jean-Eric; Raheriarisena, Martin; Goodman, Steven M

    2013-01-01

    We conducted a mitochondrial phylogeographic study of the endemic dry forest rodent Eliurus carletoni (Rodentia: Nesomyinae) in an ecological transition zone of northern Madagascar (Loky-Manambato) and 2 surrounding regions (Ankarana and Analamerana). The main goal was to assess the evolutionary consequences on this taxon of the complex landscape features and Quaternary ecological vicissitudes. Three haplogroups were identified from the 215 specimens obtained from 15 populations. High levels of genetic diversity and significant genetic differentiation among populations were observed. The different geographical subdivisions of the study area by regions, by river catchment zones, and the physical distance between populations are not correlated with genetic patterns. In contrast, population structure is mostly explained by the geographic distribution of the samples among existing forest blocks. E. carletoni experienced a genetic bottleneck between 18 750 and 7500 years BP, which correlates with periods when moister climates existed on the island. Overall, our data suggest that the complex genetic patterns of E. carletoni can be explained by Quaternary climatic vicissitudes that resulted in habitat fluctuations between dry and humid forests, as well as subsequent human-induced fragmentation of forest habitat.

  14. Habitat use by Oryzomys subflavus (Rodentia) in an open shrubland formation in Restinga de Jurubatiba National Park, RJ, Brazil.

    PubMed

    Bergallo, H G; Luz, J L; Raíces, D S; Hatano, F H; Martins-Hatano, F

    2005-11-01

    The Restinga de Jurubatiba has at least 10 plant formations, including open Clusia shrubland. This formation is composed of dense shrubs of many shapes and sizes, where Clusia hilariana is one of the most important plant species. Shrublands with Clusia (CC) are poorer in plant species and less dense than shrublands without Clusia (SC). Oryzomys subflavus (Rodentia) is the most abundant small mammal species in the open Clusia shrubland. We tested the hypothesis that the abundance of rodents would increase with the size of the patch and would be higher in SC shrublands. Rodents were captured, marked and released in three 780-m-long transects. At each capture site, we evaluated the shape of the shrubland patch, calculated the area and noted the category of the shrubland. Using ANCOVA, we ascertained whether the abundance of Oryzomys subflavus increased with the sampled area and used CC and SC shrublands differently. We also verified if the size of patches used by rodents varies in the same frequency as the size of available shrublands. Rodent abundance was found to increase significantly with the area. There were no differences in the size of the patches used by rodents and the frequency of the size of available patches. This finding indicates that O. subflavus, in the study area, is a generalist species that uses its habitat according to availability.

  15. Catalog of type specimens of recent mammals: Rodentia (Sciuromorpha and Castorimorpha) in the National Museum of Natural History, Smithsonian Institution

    USGS Publications Warehouse

    Fisher, Robert D.; Ludwig, Craig A.

    2012-01-01

    The type collection of Recent mammals in the Division of Mammals, National Museum of Natural History, Smithsonian Institution, contains 843 specimens bearing names of 820 species group taxa of Rodentia (Sciuromorpha and Castorimorpha) as of July 2011. This catalog presents a list of these holdings, which comprise 798 holotypes, 14 lectotypes, seven syntypes (30 specimens), and one neotype. In addition, we include three holotypes and 10 specimens that are part of syntype series that should be in the collection but cannot be found and three syntypes that were originally in this collection but are now known to be in other collections. One specimen that no longer has name-bearing status is included for the record. Forty-one of the names are new since the last type catalog. One new lectotype is designated. Suborders and families are listed as in Wilson and Reeder. Within families, currently recognized genera are arranged alphabetically. Within each currently recognized genus, accounts are arranged alphabetically by original published name. Information in each account includes original name and abbreviated citation thereto, current name if other than original, citation for first use of current name combination for the taxon (or new name combination if used herein for the first time), type designation, U.S. National Museum catalog number(s), preparation, age and sex, type locality, date of collection and name of collector, collector’s original number, and comments or additional information as appropriate. Digital photographs of each specimen serve as a condition report and will be linked to each electronic specimen record.

  16. Description of a new species of Ixodes Latreille, 1795 (Acari: Ixodidae) and redescription of I. lasallei Méndez & Ortiz, 1958, parasites of agoutis and pacas (Rodentia: Dasyproctidae, Cuniculidae) in Central and South America.

    PubMed

    Apanaskevich, Dmitry A; Bermúdez, Sergio E

    2017-05-01

    Ixodes bocatorensis n. sp. (Acari: Ixodidae), is described based on adults ex agoutis (Rodentia: Dasyproctidae), pacas (Rodentia: Cuniculidae) and "tapir and sloth" (Perissodactyla: Tapiridae and Pilosa) from Colombia, Panama and Venezuela. Adults of I. bocatorensis n. sp. are similar to those of I. lasallei Méndez & Ortiz, 1958 but can be distinguished by the scutum dimensions, punctation pattern, gnathosoma and palpi measurements and their ratios, basis capituli anterior angle and shape of the spur of palpal segment I ventrally. For comparative purposes the female of I. lasallei is redescribed and the true male of this species is described for the first time. Studied adults of I. lasallei were found on agoutis, pacas and ocelot (Carnivora: Felidae) in Colombia, Peru and Venezuela.

  17. The chromosome complement of Acomys spp. (Rodentia, Muridae) from Oursi, Burkina Faso--the ancestral karyotype of the cahirinus-dimidiatus group?

    PubMed

    Volobouev, V; Gautun, J C; Sicard, B; Tranier, M

    1996-11-01

    We present here data on chromosome banding analysis (R- and C-bands) of Acomys sp. (Rodentia, Muridae) from Oursi, Burkina Faso, characterized by 2n = FN = 68 and comparison of its banding patterns with those of Acomys dimidiatus from Saudi Arabia (2n = 38, FN = 70), studied previously. The study revealed complete homology between acrocentric chromosomes of Acomys sp. and chromosome arms of 16 pairs of metacentric and two pairs of acrocentric chromosomes of A. dimidiatus. In addition to monobrachial homology, one tandem translocation accompanied by a centromeric shift was identified in the karyotype of the latter species. The data obtained show that karyotypes of all the species of the Acomys cahirinus-dimidiatus group studied previously may be derived from that of Acomys sp. from Oursl by means of numerous non-homologous Rb translocations and 1-2 tandem transiocations, and thus its karyotype may be considered as ancestral for the cahirinus-dimidiatus group.

  18. Third lineage of rodent eimerians: morphology, phylogeny and re-description of Eimeria myoxi (Apicomplexa: Eimeriidae) from Eliomys quercinus (Rodentia: Gliridae).

    PubMed

    Kvičerová, Jana; Mikeš, Václav; Hypša, Václav

    2011-09-01

    Coccidian oocysts from feces of 46 individuals of the garden dormouse, Eliomys quercinus (Rodentia: Gliridae), were morphologically and molecularly characterized. Both morphological and sequence data (18S rDNA and ORF 470) showed low variability, indicating that all samples represent a single species. By comparison with published morphological descriptions of coccidia from glirid rodents, we determined that the samples represent Eimeria myoxi. Molecular data suggest that this species does not fall within the 2 known rodent-specific groups but branches as a third independent lineage. However, its exact position in respect to other eimerian clusters could not be established due to the lack of phylogenetic information at this taxonomic level for the 18S rRNA and ORF 470 genes. Based on these results, we provide a re-description of Eimeria myoxi, which contains morphological and molecular characteristics sufficient for its further unequivocal identification.

  19. The role of the subterranean rodent Ctenomys talarum (Rodentia: Octodontidae) in the life cycle of Taenia taeniaeformis (Cestoda: Taeniidae) in urban environments.

    PubMed

    Rossin, Alejandra; Malizia, Ana I; Denegri, Guillermo M

    2004-06-10

    This work is the first report of subterranean rodent Ctenomys talarum (Rodentia: Octodontidae) as intermediate host of Taenia taeniaeformis in urban areas of Mar de Cobo (Buenos Aires Province, Argentina) and to experimentally reproduce in domestic dogs the adult stage of this parasite. Prevalence, mean abundance and mean intensity of infection with T. taeniaeformis larvae in the liver and peritoneal cavity of C. talarum were 64%, 15.3 and 9.8, respectively. Ten adults of T. taeniaeformis were obtained from experimentally infected dogs. Information about the role of subterranean rodents in the life cycle of this parasite is also given. The above mentioned data indicate that T. taeniaeformis is a frequent parasite of this species of rodents, at least within the study area. Also explanations for the high prevalence of larval forms of this parasite in C. talarum populations are given.

  20. Body shape and life style of the extinct Balearic dormouse Hypnomys (Rodentia, Gliridae): new evidence from the study of associated skeletons.

    PubMed

    Bover, Pere; Alcover, Josep A; Michaux, Jacques J; Hautier, Lionel; Hutterer, Rainer

    2010-12-31

    Hypnomys is a genus of Gliridae (Rodentia) that occurred in the Balearic Islands until Late Holocene. Recent finding of a complete skeleton of the chronospecies H. morpheus (Late Pleistocene-Early Holocene) and two articulated skeletons of H. cf. onicensis (Late Pliocene) allowed the inference of body size and the calculation of several postcranial indexes. We also performed a Factorial Discriminant Analysis (FDA) in order to evaluate locomotory behaviour and body shape of the taxa. Using allometric models based on skull and tooth measurements, we calculated a body weight between 173 and 284 g for H. morpheus, and direct measurements of articulated skeletons yielded a Head and Body Length (HBL) of 179 mm and a Total Body Length of 295 mm for this species. In addition to the generally higher robustness of postcranial bones already recorded by previous authors, H. morpheus, similar to Canariomys tamarani, another extinct island species, displayed elongated zygopodium bones of the limbs and a wider distal humerus and femur than in an extant related taxon, Eliomys quercinus. Indexes indicated that Hypnomys was more terrestrial and had greater fossorial abilities than E. quercinus. This was also corroborated by a Discriminant Analysis, although no clear additional inference of locomotory abilities could be calculated.

  1. New families of site-specific repetitive DNA sequences that comprise constitutive heterochromatin of the Syrian hamster (Mesocricetus auratus, Cricetinae, Rodentia).

    PubMed

    Yamada, Kazuhiko; Kamimura, Eikichi; Kondo, Mariko; Tsuchiya, Kimiyuki; Nishida-Umehara, Chizuko; Matsuda, Yoichi

    2006-02-01

    We molecularly cloned new families of site-specific repetitive DNA sequences from BglII- and EcoRI-digested genomic DNA of the Syrian hamster (Mesocricetus auratus, Cricetrinae, Rodentia) and characterized them by chromosome in situ hybridization and filter hybridization. They were classified into six different types of repetitive DNA sequence families according to chromosomal distribution and genome organization. The hybridization patterns of the sequences were consistent with the distribution of C-positive bands and/or Hoechst-stained heterochromatin. The centromeric major satellite DNA and sex chromosome-specific and telomeric region-specific repetitive sequences were conserved in the same genus (Mesocricetus) but divergent in different genera. The chromosome-2-specific sequence was conserved in two genera, Mesocricetus and Cricetulus, and a low copy number of repetitive sequences on the heterochromatic chromosome arms were conserved in the subfamily Cricetinae but not in the subfamily Calomyscinae. By contrast, the other type of repetitive sequences on the heterochromatic chromosome arms, which had sequence similarities to a LINE sequence of rodents, was conserved through the three subfamilies, Cricetinae, Calomyscinae and Murinae. The nucleotide divergence of the repetitive sequences of heterochromatin was well correlated with the phylogenetic relationships of the Cricetinae species, and each sequence has been independently amplified and diverged in the same genome.

  2. Body Shape and Life Style of the Extinct Balearic Dormouse Hypnomys (Rodentia, Gliridae): New Evidence from the Study of Associated Skeletons

    PubMed Central

    Bover, Pere; Alcover, Josep A.; Michaux, Jacques J.; Hautier, Lionel; Hutterer, Rainer

    2010-01-01

    Hypnomys is a genus of Gliridae (Rodentia) that occurred in the Balearic Islands until Late Holocene. Recent finding of a complete skeleton of the chronospecies H. morpheus (Late Pleistocene-Early Holocene) and two articulated skeletons of H. cf. onicensis (Late Pliocene) allowed the inference of body size and the calculation of several postcranial indexes. We also performed a Factorial Discriminant Analysis (FDA) in order to evaluate locomotory behaviour and body shape of the taxa. Using allometric models based on skull and tooth measurements, we calculated a body weight between 173 and 284 g for H. morpheus, and direct measurements of articulated skeletons yielded a Head and Body Length (HBL) of 179 mm and a Total Body Length of 295 mm for this species. In addition to the generally higher robustness of postcranial bones already recorded by previous authors, H. morpheus, similar to Canariomys tamarani, another extinct island species, displayed elongated zygopodium bones of the limbs and a wider distal humerus and femur than in an extant related taxon, Eliomys quercinus. Indexes indicated that Hypnomys was more terrestrial and had greater fossorial abilities than E. quercinus. This was also corroborated by a Discriminant Analysis, although no clear additional inference of locomotory abilities could be calculated. PMID:21209820

  3. Catalog of type specimens of recent mammals: orders Didelphimorpha through Chiroptera (Excluding Rodentia) in the National Museum of Natural History, Smithsonian Institution

    USGS Publications Warehouse

    Fisher, Robert D.; Ludwig, Craig A.

    2015-01-01

    The type collection of Recent Mammals in the Division of Mammals, National Museum of Natural History, Smithsonian Institution, contains 820 specimens bearing names of 809 species-group taxa of Didelphimorphia through Chiroptera, excluding Rodentia, as of June 2014. This catalog presents an annotated list of these holdings comprised of 788 holotypes, 26 lectotypes, 11 syntypes (22 specimens), and 4 neotypes. Included are several specimens that should be in the collection but cannot be found or are now known to be in other collections. One hundred and twenty-seven of the names are new since the last type catalog covering these orders, Poole and Schantz (1942). Five specimens reported in Poole and Schantz (1942) were subsequently sent to the Vertebrate Paleontology collection and are not included here. Orders and families are ordered as in Wilson and Reeder (2005); within families, currently recognized genera are arranged alphabetically; within each currently recognized genus, accounts are arranged alphabetically by original published name. Information in each account includes original name and abbreviated citation thereto, current name if other than original, citation for first use of current name combination for the taxon (or new name combination if used herein for the first time), type designation, U.S. National Museum catalog number(s), preparation, age and sex, date of collection and collector, original collector number, type locality, and remarks as appropriate. Digital photographs of each specimen will serve as a condition report and will be attached to each electronic specimen record.

  4. Catalog of type specimens of recent mammals: Rodentia (Myomorpha, Anomaluromorpha, and Hystricomorpha) in the National Museum of Natural History, Smithsonian Institution

    USGS Publications Warehouse

    Fisher, Robert D.; Ludwig, Craig A.

    2014-01-01

    The type collection of Recent mammals in the Division of Mammals, National Museum of Natural History, Smithsonian Institution, contains 945 specimens bearing names of 931 species-group taxa of Rodentia (Myomorpha, Anomaluromorpha, and Hystricomorpha) as of August 2013. This catalog presents an annotated list of these holdings comprised of 905 holotypes, 16 lectotypes, 8 syntypes (48 specimens), and 2 neotypes. In addition, we include 44 specimens that are part of syntype series that should be in the collection but cannot be found or are now known to be in other collections. One hundred and ten of the names are new since the last type catalog covering these suborders A lectotype for Mus peruvianus Peale, 1848, is newly designated herein. Nine specimens previously reported were subsequently sent to the vertebrate paleontology collection and are not included here. Suborders and families are ordered as in Carleton and Musser; within families, currently recognized genera are arranged alphabetically; within each currently recognized genus, accounts are arranged alphabetically by original published name. Information in each account includes original name and abbreviated citation thereto, current name if other than original, citation for first use of current name combination for the taxon (or new name combination if used herein for the first time), type designation, U.S. National Museum catalog number(s), preparation, age and sex, date of collection and collector, original collector number, type locality, and remarks as appropriate. Digital photographs of each specimen will serve as a condition report and will be attached to each electronic specimen record.

  5. Analysis of gamasid mites (Acari: Mesostigmata) associated with the Asian house rat, Rattus tanezumi (Rodentia: Muridae) in Yunnan Province, southwest China.

    PubMed

    Huang, Li-Qin; Guo, Xian-Guo; Speakman, John R; Dong, Wen-Ge

    2013-05-01

    During a survey lasting from 1990 to 2008, we captured 4,113 Asian house rats, Rattus tanezumi Temminck 1844 (Rodentia: Muridae) from 28 counties of Yunnan Province in southwestern China. From these rats, a total of 19,304 gamasid mites (Acari: Mesostigmata) were collected and identified as comprising 50 different species. The species diversity of gamasid mites from this single rat species is higher than that reported previously from multiple hosts within a given geographical region. Of the 50 mite species, 31 species belonged to ectoparasites and 19 species belonged to free-living mites. The species diversity of the mites from rats trapped outdoors was much higher than from rats trapped indoors. The parameter K from the negative binomial distribution was used to measure the spatial distribution patterns of the dominant mite species and revealed that all the mites had an aggregated distribution among the rat hosts. Most mite species showed a predominantly female-biased population structure with many more females than males.

  6. Rodentia and lagomorpha

    USGS Publications Warehouse

    Sheffield, S.R.; Sawicka-Kapusta, K.; Cohen, J.B.; Rattner, B.A.; Shore, Richard F.; Rattner, Barnett A.

    2001-01-01

    This comprehensive review examines the extensive literature on wild rodents and lagomorphs as biomonitors of environmental contamination. This chapter covers studies dealing with exposure and effects of environmental contaminants on rodent and lagomorph species, including pesticides (organochlorines, organophosphorus and carbamate compounds, herbicides, plant growth regulators, fungicides, and rodenticides), other organic chemicals, metals, radionuclides, and other miscellaneous contaminants. Many research needs become evident when reviewing ecotoxicological data for rodents and lagomorphs, the most striking being the paucity of information on rodent families other than Muridae (mice and rats). While our ability to qualitatively extrapolate effects observed in laboratory studies to field situations is good for a variety of contaminants, quantitative predictions of dose-response relationships are poor because inter-specific variation and differences in exposure patterns between laboratory and wild species to toxicants are for the most part unknown. More sophisticated comparative toxicity studies need to be undertaken that build on previous work in order to develop a database of information, to account for and model differences in exposure pathways, to document interactions among multiple stressors, to generate data establishing thresholds, critical concentrations, and diagnostic guidelines, and even to develop physiologically-based toxicokinetic models. Such efforts may enhance our ability to predict effects on wild populations, including threatened and endangered species.

  7. Functional differentiation of trailing and leading forelimbs during locomotion on the ground and on a horizontal branch in the European red squirrel (Sciurus vulgaris, Rodentia).

    PubMed

    Schmidt, André

    2011-06-01

    Mammalian locomotion is characterized by the frequent use of in-phase gaits in which the footfalls of the left and right fore- or hindlimbs are unevenly spaced in time. Although previous studies have identified a functional differentiation between the first limb (trailing limb) and the second limb (leading limb) to touch the ground during terrestrial locomotion, the influence of a horizontal branch on limb function has never been explored. To determine the functional differences between trailing and leading forelimbs during locomotion on the ground and on a horizontal branch, X-ray motion analysis and force measurements were carried out in two European red squirrels (Sciurus vulgaris, Rodentia). The differences observed between trailing and leading forelimbs were minimal during terrestrial locomotion, where both limbs fulfill two functions and go through a shock-absorbing phase followed by a generating phase. During locomotion on a horizontal branch, European red squirrels reduce speed and all substrate reaction forces transmitted may be due to the reduction of vertical oscillation of the center of mass. Further adjustments during locomotion on a horizontal branch differ significantly between trailing and leading forelimbs and include limb flexion, lead intervals, limb protraction and vertical displacement of the scapular pivot. Consequently, trailing and leading forelimbs perform different functions. Trailing forelimbs function primarily as shock-absorbing elements, whereas leading forelimbs are characterized by a high level of stiffness. This functional differentiation indicates that European red squirrels 'test' the substrate for stability with the trailing forelimb, while the leading forelimb responds to or counteracts swinging or snapping branches.

  8. The mammalian 2'-5' oligoadenylate synthetase gene family: evidence for concerted evolution of paralogous Oas1 genes in Rodentia and Artiodactyla.

    PubMed

    Perelygin, Andrey A; Zharkikh, Andrey A; Scherbik, Svetlana V; Brinton, Margo A

    2006-10-01

    Multiple 2'-5' oligoadenylate (2-5A) synthetases are important components of innate immunity in mammals. Gene families encoding these proteins have previously been studied mainly in humans and mice. To reconstruct the evolution of this gene family in mammals, a search for additional 2-5A synthetase genes was performed in rat, cattle, pig, and dog. Twelve 2'-5' oligoadenylate synthetase (Oas) genes were identified in the rat genome, including eight Oas1 genes, two Oas1 pseudogenes, single copies of Oas2 and Oas3, and two Oas-like genes, Oasl1 and Oasl2. Four OAS genes were detected in the pig genome and five OAS genes were found in both the cattle and dog genomes. An OAS3 gene was not found in either the cattle or the pig genome. While two tandemly duplicated OAS-like (OASL) genes were identified in the dog genome, only a single OASL orthologue was found in both the cattle and the pig genomes. The bovine and porcine OASL genes contain premature stop codons and encode truncated proteins, which lack the typical C-terminal double ubiquitin domains. The cDNA sequences of the rat, cattle, pig, and dog OAS genes were amplified, sequenced and compared with each other and with those in the human, mouse, horse, and chicken genomes. Evidence of concerted evolution of paralogous 2'-5' oligoadenylate synthetase 1 genes was obtained in rodents (Rodentia) and even-toed ungulates (Artiodactyla). Calculations using the nonparametric Kolmogorov-Smirnov test suggested that the homogenization of paralogous OAS1 sequences was due to gene conversion rather than stabilizing selection.

  9. A Golgi study of the sixth layer of the cerebral cortex. I. The lissencephalic brain of Rodentia, Lagomorpha, Insectivora and Chiroptera.

    PubMed Central

    Ferrer, I; Fabregues, I; Condom, E

    1986-01-01

    A study of the morphological characteristics of the neurons in layer VI of the cerebral cortex was carried out using the rapid Golgi method in several lissencephalic species including Rodentia (rat, mouse, vole (Microtus agrestis) and hamster), Lagomorpha (rabbit), Insectivora (hedgehog) and in the Chiroptera the dwarf bat (Pipistrellus pipistrellus). There was a basic uniformity in the structure of the sixth layer. Main neuronal types in lamina VIa were large pyramidal neurons, triangular or atypical pyramidal cells, multiapical pyramidal neurons, inverted pyramids, fusiform neurons, Martinotti cells and bi-tufted cells. Main neuronal types in lamina VIb were medium sized, flattened pyramids, large and small horizontal neurons, horizontal pyramidal cells, fan shaped neurons and multipolar spinous neurons with long descending axons. Sparsely spinous and spine-free multipolar neurons with short axons were present in the two laminae of layer VI, but sparsely spinous neurons with axons similar to those found in basket cells of other layers of the cortex were observed mainly in lamina VIa. Neuronal subsystems were tentatively classified on the basis of the course of the axons. Pyramidal neurons, fusiform neurons, multiapical pyramidal cells, inverted pyramidal cells, fan shaped neurons and multipolar neurons with large descending axons were interpreted as being the main source of long projection and association connections. Large horizontal neurons were interpreted as possible ipsilateral association neurons because the horizontal course of the axons over long distances followed the boundary of the deeper region of the sixth layer. Three intracortical (association) subsystems were included. Axons of Martinotti cells and collateral ascending axons of pyramidal neurons (including multiapical pyramidal neurons) formed the ascending interlaminar fibrillary subsystem. Axons of small horizontal cells and horizontal collaterals of pyramidal neurons formed the horizontal

  10. Myocoptid mites (Acariformes: Myocoptidae) of the fauna of the former USSR.

    PubMed

    Bochkov, Andre V

    2016-11-17

    Mites of the family Myocoptidae (Acariformes: Sarcoptoidea) of the former USSR are revised based on the collection of the Zoological Institute RAS (St. Petersburg, Russia). Seventeen described species are recorded. Four species are described as new for science: Trichoecius dubininae sp. nov. from Lasiopodomys gregalis (Pallas) (Rodentia: Cricetidae) from Russia (Chelyabinsk Prov., type locality), Kazakhstan and Kirghizia, T. lemmus sp. nov. from Lemmus sibiricus (Kerr) (Rodentia: Cricetidae) from Russia (Taymyr peninsula), T. meriones sp. nov. from Meriones meridianus (Pallas) (Rodentia: Muridae) from Turkmenia, and Myocoptes meriones sp. nov. from Meriones tamariscinus (type host) from Kirghizia (type locality) and Meriones libycus (Lichtenstein) from Tajikistan. In addition, the presence of 7 more species in the fauna of the former USSR is considered highly probable. Myocoptids of the former USSR represent all 6 genera currently recognized in the family. Keys to species, their hosts and localities are provided and all data are summarized in tabular format. A new name Apocalyptoides nom. nov. is proposed for the preoccupied generic name Apocalypsis Bochkov, 2010 not Butler (1876).

  11. Capture of syncytin-Mar1, a Fusogenic Endogenous Retroviral Envelope Gene Involved in Placentation in the Rodentia Squirrel-Related Clade

    PubMed Central

    Redelsperger, François; Cornelis, Guillaume; Vernochet, Cécile; Tennant, Bud C.; Catzeflis, François; Mulot, Baptiste; Heidmann, Odile; Dupressoir, Anne

    2014-01-01

    ABSTRACT Syncytin genes are fusogenic envelope protein (env) genes of retroviral origin that have been captured for a function in placentation. Within rodents, two such genes have previously been identified in the mouse-related clade, allowing a demonstration of their essential role via knockout mice. Here, we searched for similar genes in a second major clade of the Rodentia order, the squirrel-related clade, taking advantage of the complete sequencing of the ground squirrel Ictidomys tridecemlineatus genome. In silico search for env genes with full coding capacity identified several candidate genes with one displaying placenta-specific expression, as revealed by quantitative reverse transcription-PCR analysis of a large panel of tissues. This gene belongs to a degenerate endogenous retroviral element, with recognizable hallmarks of an integrated provirus. Cloning of the gene in an expression vector for ex vivo cell-cell fusion and pseudotype assays demonstrated fusogenicity on a large panel of mammalian cells. In situ hybridization on placenta sections showed specific expression in domains where trophoblast cells fuse into a syncytiotrophoblast at the fetomaternal interface, consistent with a role in syncytium formation. Finally, we show that the gene is conserved among the tribe Marmotini, thus dating its capture back to about at least 25 million years ago, with evidence for purifying selection and conservation of fusogenic activity. This gene that we named syncytin-Mar1 is distinct from all seven Syncytin genes identified to date in eutherian mammals and is likely to be a major effector of placentation in its related clade. IMPORTANCE Syncytin genes are fusogenic envelope genes of retroviral origin, ancestrally captured for a function in placentation. Within rodents, two such genes had been previously identified in the mouse-related clade. Here, in the squirrel-related rodent clade, we identified the envelope gene of an endogenous retrovirus with all the

  12. Capture of syncytin-Mar1, a fusogenic endogenous retroviral envelope gene involved in placentation in the Rodentia squirrel-related clade.

    PubMed

    Redelsperger, François; Cornelis, Guillaume; Vernochet, Cécile; Tennant, Bud C; Catzeflis, François; Mulot, Baptiste; Heidmann, Odile; Heidmann, Thierry; Dupressoir, Anne

    2014-07-01

    Syncytin genes are fusogenic envelope protein (env) genes of retroviral origin that have been captured for a function in placentation. Within rodents, two such genes have previously been identified in the mouse-related clade, allowing a demonstration of their essential role via knockout mice. Here, we searched for similar genes in a second major clade of the Rodentia order, the squirrel-related clade, taking advantage of the complete sequencing of the ground squirrel Ictidomys tridecemlineatus genome. In silico search for env genes with full coding capacity identified several candidate genes with one displaying placenta-specific expression, as revealed by quantitative reverse transcription-PCR analysis of a large panel of tissues. This gene belongs to a degenerate endogenous retroviral element, with recognizable hallmarks of an integrated provirus. Cloning of the gene in an expression vector for ex vivo cell-cell fusion and pseudotype assays demonstrated fusogenicity on a large panel of mammalian cells. In situ hybridization on placenta sections showed specific expression in domains where trophoblast cells fuse into a syncytiotrophoblast at the fetomaternal interface, consistent with a role in syncytium formation. Finally, we show that the gene is conserved among the tribe Marmotini, thus dating its capture back to about at least 25 million years ago, with evidence for purifying selection and conservation of fusogenic activity. This gene that we named syncytin-Mar1 is distinct from all seven Syncytin genes identified to date in eutherian mammals and is likely to be a major effector of placentation in its related clade. Importance: Syncytin genes are fusogenic envelope genes of retroviral origin, ancestrally captured for a function in placentation. Within rodents, two such genes had been previously identified in the mouse-related clade. Here, in the squirrel-related rodent clade, we identified the envelope gene of an endogenous retrovirus with all the features of a

  13. New species and records of mites of the superfamily Sarcoptoidea (Acariformes: Psoroptidia) from mammals in Brazil.

    PubMed

    Bochkov, Andre V; Valim, Michel P

    2016-01-01

    Sixteen species of the superfamily Sarcoptoidea (Acariformes: Psoroptidia) belonging to 10 genera of the families Atopomelidae, Listrophoridae, Chirodiscidae, and Listropsoralgidae are recorded in Brazil. Among them, three species, Prolistrophorus hylaeamys sp. nov. from Hylaeamys laticeps (Lund, 1840) (Cricetidae: Sigmodontinae) from Minas Gerais, Lynxacarus serrafreirei sp. nov. from Galictis cuja (Molina, 1782) (Carnivora: Mustelidae) from Rio de Janeiro (Listrophoridae), and Didelphoecius micoureus sp. nov. (Atopomelidae) from Micoureus paraguayanus (Tate, 1931) (Didelphimorphia: Didelphidae) from Minas Gerais are described as new for science. Three species of the family Listrophoridae, Prolistrophorus bidentatus Fain et Lukoschus, 1984 from Akodon cursor (Winge, 1887) (Rodentia: Cricetidae) (new host), Prolistrophorus ctenomys Fain, 1970 from Ctenomys torquatus Lichtenstein, 1830 (Rodentia: Ctenomyidae) (new host), and Leporacarus sylvilagi Fain, Whitaker et Lukoschus, 1981 from Sylvilagus brasiliensis (Linnaeus, 1758) (Lagomorpha: Leporidae) (new host) -from Minas Gerais and Rio Grande do Sul, and one species of the family Chirodiscidae, Parakosa tadarida McDaniel and Lawrence, 1962 from Molossus molossus (Pallas, 1766) (Chiroptera: Molossidae) are recorded for the first time in Brazil. The previously unknown female of Didelphoecius validus Fain, Zanatta-Coutinho et Fonseca, 1996 (Atopomelidae) from Metachirus nudicaudatus (Geoffroy, 1803) (Didelphimorphia: Didelphidae) from Minas Gerais is described. All data on host-parasite associations of sarcoptoids in Brazil are summarized. Totally, 61 sarcoptoid species of 8 families are recorded in Brazil.

  14. A novel satellite DNA sequence in the Peromyscus genome (PMSat): Evolution via copy number fluctuation.

    PubMed

    Louzada, Sandra; Vieira-da-Silva, Ana; Mendes-da-Silva, Ana; Kubickova, Svatava; Rubes, Jiri; Adega, Filomena; Chaves, Raquel

    2015-11-01

    Satellite DNAs (satDNA) are tandemly arrayed repeated sequences largely present in eukaryotic genomes, which play important roles in genome evolution and function, and therefore, their analysis is vital. Here, we describe the isolation of a novel satellite DNA family (PMSat) from the rodent Peromyscus eremicus (Cricetidae, Rodentia), which is located in pericentromeric regions and exhibits a typical satellite DNA genome organization. Orthologous PMSat sequences were isolated and characterized from three species belonging to Cricetidae: Cricetus cricetus, Phodopus sungorus and Microtus arvalis. In these species, PMSat is highly conserved, with the absence of fixed species-specific mutations. Strikingly, different numbers of copies of this sequence were found among the species, suggesting evolution by copy number fluctuation. Repeat units of PMSat were also found in the Peromyscus maniculatus bairdii BioProject, but our results suggest that these repeat units are from genome regions outside the pericentromere. The remarkably high evolutionary sequence conservation along with the preservation of a few numbers of copies of this sequence in the analyzed genomes may suggest functional significance but a different sequence nature/organization. Our data highlight that repeats are difficult to analyze due to the limited tools available to dissect genomes and the fact that assemblies do not cover regions of constitutive heterochromatin.

  15. Ocular comparative anatomy of the family Rodentia.

    PubMed

    Rodriguez-Ramos Fernandez, Julia; Dubielzig, Richard R

    2013-07-01

    There is little information regarding ocular anatomy and histology in many of the rodent species. Histological analyses for morphologic features were performed in 31 globes from 18 rodent species submitted to and archived at the Comparative Ocular Pathology Laboratory of Wisconsin. The following measurements were taken: thickness of the cornea, corneal epithelium, corneal stroma, Descemet's membrane, and retina. H&E sections were evaluated for the following anatomical features: presence of pigmented epithelial cells in the peripheral cornea, presence and location of Schlemm's canal, presence of iridal sphincter and dilator and ciliary body muscles, presence of pars plicata and plana, presence of retinal vessels, presence of lamina cribrosa, and presence of tapetum lucidum. The springhaas was the only rodent in our collection that presented a well-developed tapetum lucidum fibrosum. The presence of retinal vessels was variable: vessels were observed in all of the members of the mouse-related clade, except the springhaas and the beaver, in all of the squirrel-related clade members, and in none of the Ctenohystrica. In the flying squirrels, blood vessels extended to the outer limiting membrane in the photoreceptor layer. Beavers, chinchillas, capybara, and guinea pigs lacked vessels within the retina; however, they had vessels within the optic nerve head. Ground squirrels have an optic nerve head, which is linear in the horizontal plane and an asymmetric retina. The tree-dwelling squirrels have a rounded but still elongated optic nerve, and the flying squirrel has a round optic nerve head like all the other rodents.

  16. Molecular diversification of Trichuris spp. from Sigmodontinae (Cricetidae) rodents from Argentina based on mitochondrial DNA sequences.

    PubMed

    Callejón, Rocío; Robles, María Del Rosario; Panei, Carlos Javier; Cutillas, Cristina

    2016-08-01

    A molecular phylogenetic hypothesis is presented for the genus Trichuris based on sequence data from mitochondrial cytochrome c oxidase 1 (cox1) and cytochrome b (cob). The taxa consisted of nine populations of whipworm from five species of Sigmodontinae rodents from Argentina. Bayesian Inference, Maximum Parsimony, and Maximum Likelihood methods were used to infer phylogenies for each gene separately but also for the combined mitochondrial data and the combined mitochondrial and nuclear dataset. Phylogenetic results based on cox1 and cob mitochondrial DNA (mtDNA) revealed three clades strongly resolved corresponding to three different species (Trichuris navonae, Trichuris bainae, and Trichuris pardinasi) showing phylogeographic variation, but relationships among Trichuris species were poorly resolved. Phylogenetic reconstruction based on concatenated sequences had greater phylogenetic resolution for delimiting species and populations intra-specific of Trichuris than those based on partitioned genes. Thus, populations of T. bainae and T. pardinasi could be affected by geographical factors and co-divergence parasite-host.

  17. Pericentric satellite DNA and molecular phylogeny in Acomys (Rodentia).

    PubMed

    Kunze, B; Traut, W; Garagna, S; Weichenhan, D; Redi, C A; Winking, H

    1999-01-01

    Satellite DNAs (stDNAs) of four Acomys species (spiny-mice), A. cahirinus, A. cineraceus, A. dimidiatus and A. russatus, belong to closely related sequence families. Monomer sizes range from 338 to 364 bp. Between-species sequence identity was from 81.0% to 97.2%. The molecular phylogeny of the sequences helps to clarify the taxonomy of this 'difficult' group. The A. dimidiatus genome contains about 60000 repeats. According to the restriction patterns, repeats are arranged in tandem. The stDNA maps to the centromeric heterochromatin of most autosomes, both acrocentric and metacentric, but appears to be absent in the centromeric region of Y chromosomes. A well-conserved centromere protein B (CENP-B) box is present in the stDNA of A. russatus while it is degenerated in the other species.

  18. Chromosome Polymorphism in Microtus (Alexandromys) mujanensis (Arvicolinae, Rodentia).

    PubMed

    Lemskaya, Natalya A; Kartavtseva, Irina V; Rubtsova, Nadezhda V; Golenishchev, Fedor N; Sheremetyeva, Irina N; Graphodatsky, Alexander S

    2015-01-01

    The Muya Valley vole (Microtus mujanensis) has a constant diploid chromosome number of 2n = 38, but an unstable karyotype with polymorphic chromosome pairs. Here, we describe 4 karyotypic variants involving 2 polymorphic chromosome pairs, MMUJ8 and MMUJ14, in 6 animals from Buryatia using a combination of GTG-banding and chromosome painting with M. agrestis probes. We suggest that the polymorphic pairs MMUJ8 and MMUJ14 were formed through pericentric inversions that played a major role during karyotype evolution of the species. We also propose that the stable diploid number with some ongoing polymorphism in the number of chromosome arms indicates that this evolutionarily young endemic species of Russian Far East is on the way to karyotype and likely species stabilization.

  19. Complete mitochondrial genome of Lasiopodomys mandarinus mandarinus (Arvicolinae, Rodentia).

    PubMed

    Li, Yangwei; Lu, Jiqi; Wang, Zhenlong

    2016-01-01

    Mandarin voles (Lasiopodomys mandarinus) is a subterranean rodent species that are often used as a model for studying subterranean hypoxic stress in mammals. Its subspecies L. m. mandarinus span in cropland in most area of north China and is regarded as an agricultural pest. In this paper, the complete mitochondrial genome of L. m. mandarinus has been determined. Our results showed that the mitochondrial genome of L. m. mandarinus is a circular molecule of 16,367 bp, which contents 13 protein-coding, 22 tRNAs and 2 rRNAs genes. The overall base composition of the heavy strand is 32.47% A, 27.04% T, 27.01% C, and 13.47% G. with an AT content of 59.51%.

  20. [Ovarian activity of Agouti paca (Rodentia: Agoutidae) under captivity].

    PubMed

    Montes Pérez, Rubén C; Cabrera Baz, Elsy A

    2006-09-01

    The ovarian activity of Agouti paca was characterized by hormonal profiles and ovarian structures. Samples of blood were taken from eight females (seven adults and one juvenile) at the breeding grounds of the Facultad de Medicina Veterinaria y Zootecnia in Yucatśn, Mexico. Sampling lasted approximately two months and was done every three and six days. Blood was collected from anesthetized animals, and the levels of progesterone (P4) and 17 beta estradiol (E2) were analized by radioimmunoassay technique. Macroscopic and microscopic analyses were carried out in ovaries of dead animals. The estrous cycle lasted 29+/-8.4 days, levels of 1.61+/-0.65 ng/ml for P4 and 39+/-24 pg/ml for E2 were observed for a follicular phase, 6.18+/-3.70 ng/ml and 29+/-16 pg/ml for P4 and E2 respectively in the luteal phase. Statistically significant differences were found between phases for P4 but not for E2. The presence of extragonadal steroids with levels of P4 of 1.9+/-0.77 ng/ml and E2 of 22+/-17 pg/ml were observed, which are not produced by the effects of managing stress. The changes in the levels of P4 during the cycle are indicators of luteal activity, with the intersticial tissue acting probably as active steroids-producing gland. Follicular growth was observed during the entire cycle.

  1. Mastomys (rodentia: muridae) species distinguished by hemoglobin pattern differences.

    PubMed

    Robbins, C B; Krebs, J W; Johnson, K M

    1983-05-01

    Hemoglobin electrophoresis patterns were found to be reliable markers for distinguishing two species of Mastomys in Sierra Leone having 32 and 38 chromosomes. All 32-chromosome animals exhibited a single hemoglobin pattern, whereas those with 38-chromosomes had four distinguishable patterns. Both karyotypes were present throughout Sierra Leone. The 38-chromosome species was more prevalent in the Guinea savanna zone to the north, while the 32-chromosome species was most dominant in human-modified high forest areas of the eastern and southern parts of the country. In almost all situations the 32-chromosome species was more common in houses than in bush habitats; the reverse was true for Mastomys having 38 chromosomes. Analysis of hemoglobin patterns thus becomes useful for species identification, and is necessary to understand the roles of the different Mastomys forms as reservoirs of human diseases, such as Lassa fever in West Africa.

  2. Phylogeographic Study of Apodemus ilex (Rodentia: Muridae) in Southwest China

    PubMed Central

    Kilpatrick, C. William; Liu, Shao-Ying; Yu, Fa-Hong; Jiang, Xue-Long

    2012-01-01

    Background The Mountains of southwest China have complex river systems and a profoundly complex topography and are among the most important biodiversity hotspots in the world. However, only a few studies have shed light on how the mountains and river valleys promote genetic diversity. Apodemus ilex is a fine model for investigating this subject. Methodology/Principal Findings To assess the genetic diversity and biogeographic patterns of Apodemus ilex, the complete cytochrome b gene sequences (1,140 bp) were determined from 203 samples of A. draco/ilex that were collected from southwest China. The results obtained suggested that A. ilex and A. draco are sistergroups and diverged from each other approximately 2.25 million years ago. A. ilex could be divided into Eastern and Western phylogroups, each containing two sub-groups and being widespread in different geographical regions of the southern Hengduan Mountains and the western Yunnan - Guizhou Plateau. The population expansions of A. ilex were roughly from 0.089 Mya to 0.023 Mya. Conclusions Our result suggested that A. ilex is a valid species rather than synonym of A. draco. As a middle-high elevation inhabitant, the phylogenetic pattern of A. ilex was strongly related to the complex geographical structures in southwest China, particularly the existence of deep river valley systems, such as the Mekong and Salween rivers. Also, it appears that the evolutionary history of A. ilex, such as lineage divergences and population expansions were strongly affected by climate fluctuation in the Late Pleistocene. PMID:22347481

  3. Dietary Ecology of Murinae (Muridae, Rodentia): A Geometric Morphometric Approach

    PubMed Central

    Gómez Cano, Ana Rosa; Hernández Fernández, Manuel; Álvarez-Sierra, M. Ángeles

    2013-01-01

    Murine rodents represent a highly diverse group, which displays great ecological versatility. In the present paper we analyse the relationship between dental morphology, on one hand, using geometric morphometrics based upon the outline of first upper molar and the dietary preference of extant murine genera, on the other. This ecomorphological study of extant murine rodents demonstrates that dietary groups can be distinguished with the use of a quantitative geometric morphometric approach based on first upper molar outline. A discriminant analysis of the geometric morphometric variables of the first upper molars enables us to infer the dietary preferences of extinct murine genera from the Iberian Peninsula. Most of the extinct genera were omnivore; only Stephanomys showed a pattern of dental morphology alike that of the herbivore genera. PMID:24236090

  4. Late Pleistocene voles (Arvicolinae, Rodentia) from the Baranica Cave (Serbia)

    NASA Astrophysics Data System (ADS)

    Bogićević, Katarina; Nenadić, Draženko; Mihailović, Dušan

    2012-02-01

    Baranica is a cave system situated in the south-eastern part of Serbia, four kilometers south to Knjaževac, on the right bank of the Trgovi\\vski Timok. The investigations in Baranica were conducted from 1994 to 1997 by the Faculty of Philosophy from Belgrade and the National Museum of Knjaževac. Four geological layers of Quaternary age were recovered. The abundance of remains of both large and small mammals was noticed in the early phase of the research. In this paper, the remains of eight vole species are described: Arvicola terrestris (Linnaeus, 1758), Chionomys nivalis (Martins, 1842), Microtus (Microtus) arvalis (Pallas, 1778) and Microtus (Microtus) agrestis (Linnaeus, 1761), Microtus (Stenocranius) gregalis (Pallas, 1779), Microtus (Terricola) subterraneus (de Sélys-Longchamps, 1836), Clethrionomys glareolus (Schreber, 1780) and Lagurus lagurus (Pallas, 1773). Among them, steppe and open area inhabitants prevail. Based on the evolutionary level and dimensions of the Arvicola terrestris molars, as well as the overall characteristics of the fauna, it was concluded that the deposits were formed in the last glacial period of the Late Pleistocene. These conclusions are rather consistent with the absolute dating of large mammal bones (23.520 ± 110 B.P. for Layer 2 and 35.780 ± 320 B.P. for Layer 4).

  5. Diversity and Karyotypic Evolution in the Genus Neacomys (Rodentia, Sigmodontinae).

    PubMed

    da Silva, Willam O; Pieczarka, Julio C; Rossi, Rogério V; Schneider, Horacio; Sampaio, Iracilda; Miranda, Cleuton L; da Silva, Cláudia R; Cardoso, Elizandra M; Nagamachi, Cleusa Y

    2015-01-01

    Neacomys (Sigmodontinae) comprises 8 species mainly found in the Amazonian region. We describe 5 new karyotypes from Brazilian Amazonia: 2 cytotypes for N. paracou (2n = 56/FNa = 62-66), 1 for N. dubosti (2n = 64/FNa = 68), and 2 for Neacomys sp. (2n = 58/FNa = 64-70), with differences in the 18S rDNA. Telomeric probes did not show ITS. We provide a phylogeny using Cytb, and the analysis suggests that 2n = 56 with a high FNa is ancestral for the genus, as found in N. paracou, being retained by the ancestral forms of the other species, with an increase in 2n occurring independently in N. spinosus and N. dubosti. Alternatively, an increase in 2n may have occurred in the ancestral taxon of the other species, followed by independent 2n-reduction events in Neacomys sp. and in the ancestral species of N. tenuipes, N. guianae, N. musseri, and N. minutus. Finally, a drastic reduction event in the diploid number occurred in the ancestral species of N. musseri and N. minutus which exhibit the lowest 2n of the genus. The karyotypic variations found in both intra- and interspecific samples, associated with the molecular phylogeny, suggest a chromosomal evolution with amplification/deletion of constitutive heterochromatin and rearrangements including fusions, fissions, and pericentric inversions.

  6. Mesoamerican tree squirrels evolution (Rodentia: Sciuridae): a molecular phylogenetic analysis.

    PubMed

    Villalobos, Federico; Gutierrez-Espeleta, Gustavo

    2014-06-01

    The tribe Sciurini comprehends the genera Sciurus, Syntheosiurus, Microsciurus, Tamiasciurus and Rheinthrosciurus. The phylogenetic relationships within Sciurus have been only partially done, and the relationship between Mesoamerican species remains unsolved. The phylogenetic relationships of the Mesoamerican tree squirrels were examined using molecular data. Sequence data publicly available (12S, 16S, CYTB mitochondrial genes and IRBP nuclear gene) and cytochrome B gene sequences of four previously not sampled Mesoamerican Sciurus species were analyzed under a Bayesian multispecies coalescence model. Phylogenetic analysis of the multilocus data set showed the neotropical tree squirrels as a monophyletic clade. The genus Sciurus was paraphyletic due to the inclusion of Microsciurus species (M. alfari and M. flaviventer). The South American species S. aestuans and S. stramineus showed a sister taxa relationship. Single locus analysis based on the most compact and complete data set (i.e. CYTB gene sequences), supported the monophyly of the South American species and recovered a Mesoamerican clade including S. aureogaster, S. granatensis and S. variegatoides. These results corroborated previous findings based on cladistic analysis of cranial and post-cranial characters. Our data support a close relationship between Mesoamerican Sciurus species and a sister relationship with South American species, and corroborates previous findings in relation to the polyphyly of Microsciurus and Syntheosciurus paraphyly.

  7. Children's Attitudes towards Animals: Evidence from the RODENTIA Project

    ERIC Educational Resources Information Center

    Fonseca, Maria Joao; Franco, Nuno H.; Brosseron, Francis; Tavares, Fernando; Olsson, I. Anna S.; Borlido-Santos, Julio

    2011-01-01

    The instructional use of animals is a popular strategy to engage students with science, enhance their motivation, and promote values such as respect, tolerance, and empathy for all living beings. Although these beneficial outcomes are widely acknowledged, research has not provided reliable indicators of their efficiency. Therefore, it is essential…

  8. Late Pleistocene echimyid rodents (Rodentia, Hystricognathi) from northern Brazil.

    PubMed

    Ferreira, Thais M F; Olivares, Adriana Itati; Kerber, Leonardo; Dutra, Rodrigo P; Avilla, Leonardo S

    2016-06-07

    Echimyidae (spiny rats, tree rats and the coypu) is the most diverse family of extant South American hystricognath rodents (caviomorphs). Today, they live in tropical forests (Amazonian, coastal and Andean forests), occasionally in more open xeric habitats in the Cerrado and Caatinga of northern South America, and open areas across the southern portion of the continent (Myocastor). The Quaternary fossil record of this family remains poorly studied. Here, we describe the fossil echimyids found in karst deposits from southern Tocantins, northern Brazil. The analyzed specimens are assigned to Thrichomys sp., Makalata cf. didelphoides and Proechimys sp. This is the first time that a fossil of Makalata is reported. The Pleistocene record of echimyids from this area is represented by fragmentary remains, which hinders their determination at specific levels. The data reported here contributes to the understanding of the ancient diversity of rodents of this region, evidenced until now in other groups, such as the artiodactyls, cingulates, carnivores, marsupials, and squamate reptiles.

  9. Analysis of ectoparasites (chigger mites, gamasid mites, fleas and sucking lice) of the Yunnan red-backed vole (Eothenomys miletus) sampled throughout its range in southwest China.

    PubMed

    Peng, P-Y; Guo, X-G; Song, W-Y; Hou, P; Zou, Y-J; Fan, R; He, X-S

    2015-12-01

    The Yunnan red-backed vole Eothenomys miletus (Rodentia: Cricetidae) is an endemic rodent species and reservoir host of zoonoses in southwest China. Based on a large host sample (2463 voles collected from 39 localities between 2001 and 2013), a general analysis of four categories of ectoparasite (fleas, sucking lice, chigger mites and gamasid mites) on E. miletus across its entire range of distribution was made. This analysis identified a total of 71 895 ectoparasites belonging to 320 species (30 species of flea, 9 of sucking louse, 106 of gamasid mite and 175 of chigger mite) with a high prevalence (87%), mean abundance (29.19) and mean intensity (33.69). Of the 18 vector species of zoonoses found on E. miletus, the flea Ctenophthalmus quadratus (Siphonaptera: Hystrichopsyllidae) and chigger mite Leptotrombidium scutellare (Trombidiformes: Trombiculidae) were the dominant species; these are the main vectors of zoonoses in China. All of the dominant parasite species showed an aggregated distribution pattern. Male voles harboured more species of parasite than females. Chigger mites represented the most abundant species group on voles and their prevalence was positively correlated with mean abundance (r = 0.73; P < 0.05). As a single rodent species, E. miletus has a high potential to harbour abundant ectoparasites with high species diversity and high rates of infestation. The sex of the vole affects ectoparasite infestation.

  10. Spontaneous expression of magnetic compass orientation in an epigeic rodent: the bank vole, Clethrionomys glareolus

    NASA Astrophysics Data System (ADS)

    Oliveriusová, Ludmila; Němec, Pavel; Pavelková, Zuzana; Sedláček, František

    2014-07-01

    Magnetoreception has been convincingly demonstrated in only a few mammalian species. Among rodents, magnetic compass orientation has been documented in four species of subterranean mole rats and two epigeic (i.e. active above ground) species—the Siberian hamster and the C57BL/6J mouse. The mole rats use the magnetic field azimuth to determine compass heading; their directional preference is spontaneous and unimodal, and their magnetic compass is magnetite-mediated. By contrast, the primary component of orientation response is learned in the hamster and the mouse, but both species also exhibit a weak spontaneous bimodal preference in the natural magnetic field. To determine whether the magnetic compass of wild epigeic rodents features the same functional properties as that of laboratory rodents, we investigated magnetic compass orientation in the bank vole Clethrionomys glareolus (Cricetidae, Rodentia). The voles exhibited a robust spontaneous bimodal directional preference, i.e. built nests and slept preferentially along the north-south axis, and deflected their directional preference according to a shift in the direction of magnetic north, clearly indicating that they were deriving directional information from the magnetic field. Thus, bimodal, axially symmetrical directional choice seems to be a common feature shared by epigeic rodents. However, spontaneous directional preference in the bank vole appeared to be more pronounced than that reported in the hamster and the mouse. These findings suggest that bank voles are well suited for future studies investigating the adaptive significance and mechanisms of magnetic orientation in epigeic rodents.

  11. A synaptonemal complex-derived mechanism for meiotic segregation precedes the evolutionary loss of homology between sex chromosomes in arvicolid mammals.

    PubMed

    de la Fuente, Roberto; Sánchez, Antonio; Marchal, Juan Alberto; Viera, Alberto; Parra, María Teresa; Rufas, Julio S; Page, Jesús

    2012-10-01

    Synapsis and reciprocal recombination between sex chromosomes are restricted to the pseudoautosomal region. In some animal species, sex chromosomes do not present this region, although they utilize alternative mechanisms that ensure meiotic pairing and segregation. The subfamily Arvicolinae (Rodentia, Cricetidae) includes numerous species with achiasmate sex chromosomes. In order to know whether the mechanism involved in achiasmate segregation is an ancient feature in arvicolid species, we have compared the sex chromosomes of both the Mediterranean vole (Microtus duodecimcostatus) and the water vole (Arvicola terrestris). By means of immunofluorescence, we have found that sex chromosomes in M. duodecimcostatus are asynaptic and develop a synaptonemal complex-derived structure that mediates pairing and facilitates segregation. In A. terrestris, sex chromosomes are synaptic and chiasmate but also exhibit a synaptonemal complex-derived filament during anaphase I. Since phylogenetic relationships indicate that the synaptic condition is ancestral in arvicolids, this finding indicates that the mechanism for achiasmate sex chromosome segregation precedes the switching to the asynaptic condition. We discuss the origin of this synaptonemal complex-derived mechanism that, in turn, could counterbalance the disruption of homology in the sex chromosomes of those species.

  12. Shared ancestry between a newfound mole-borne hantavirus and hantaviruses harbored by cricetid rodents.

    PubMed

    Kang, Hae Ji; Bennett, Shannon N; Hope, Andrew G; Cook, Joseph A; Yanagihara, Richard

    2011-08-01

    Discovery of genetically distinct hantaviruses in multiple species of shrews (order Soricomorpha, family Soricidae) and moles (family Talpidae) contests the conventional view that rodents (order Rodentia, families Muridae and Cricetidae) are the principal reservoir hosts and suggests that the evolutionary history of hantaviruses is far more complex than previously hypothesized. We now report on Rockport virus (RKPV), a hantavirus identified in archival tissues of the eastern mole (Scalopus aquaticus) collected in Rockport, TX, in 1986. Pairwise comparison of the full-length S, M, and L genomic segments indicated moderately low sequence similarity between RKPV and other soricomorph-borne hantaviruses. Phylogenetic analyses, using maximum-likelihood and Bayesian methods, showed that RKPV shared a most recent common ancestor with cricetid-rodent-borne hantaviruses. Distributed widely across the eastern United States, the fossorial eastern mole is sympatric and syntopic with cricetid rodents known to harbor hantaviruses, raising the possibility of host-switching events in the distant past. Our findings warrant more-detailed investigations on the dynamics of spillover and cross-species transmission of present-day hantaviruses within communities of rodents and moles.

  13. Extensive Chromosomal Reorganization in the Evolution of New World Muroid Rodents (Cricetidae, Sigmodontinae): Searching for Ancestral Phylogenetic Traits

    PubMed Central

    Pereira, Adenilson Leão; Malcher, Stella Miranda; Nagamachi, Cleusa Yoshiko; O’Brien, Patricia Caroline Mary; Ferguson-Smith, Malcolm Andrew; Mendes-Oliveira, Ana Cristina; Pieczarka, Julio Cesar

    2016-01-01

    Sigmodontinae rodents show great diversity and complexity in morphology and ecology. This diversity is accompanied by extensive chromosome variation challenging attempts to reconstruct their ancestral genome. The species Hylaeamys megacephalus–HME (Oryzomyini, 2n = 54), Necromys lasiurus—NLA (Akodontini, 2n = 34) and Akodon sp.–ASP (Akodontini, 2n = 10) have extreme diploid numbers that make it difficult to understand the rearrangements that are responsible for such differences. In this study we analyzed these changes using whole chromosome probes of HME in cross-species painting of NLA and ASP to construct chromosome homology maps that reveal the rearrangements between species. We include data from the literature for other Sigmodontinae previously studied with probes from HME and Mus musculus (MMU) probes. We also use the HME probes on MMU chromosomes for the comparative analysis of NLA with other species already mapped by MMU probes. Our results show that NLA and ASP have highly rearranged karyotypes when compared to HME. Eleven HME syntenic blocks are shared among the species studied here. Four syntenies may be ancestral to Akodontini (HME2/18, 3/25, 18/25 and 4/11/16) and eight to Sigmodontinae (HME26, 1/12, 6/21, 7/9, 5/17, 11/16, 20/13 and 19/14/19). Using MMU data we identified six associations shared among rodents from seven subfamilies, where MMU3/18 and MMU8/13 are phylogenetic signatures of Sigmodontinae. We suggest that the associations MMU2entire, MMU6proximal/12entire, MMU3/18, MMU8/13, MMU1/17, MMU10/17, MMU12/17, MMU5/16, MMU5/6 and MMU7/19 are part of the ancestral Sigmodontinae genome. PMID:26800516

  14. Parasite diversity at the Holarctic nexus: species of Arostrilepis (Eucestoda: Hymenolepididae) in voles and lemmings (Cricetidae: Arvicolinae) from greater Beringia.

    PubMed

    Makarikov, Arseny A; Galbreath, Kurt E; Hoberg, Eric P

    2013-01-23

    Previously unrecognized species of hymenolepidid cestodes attributable to Arostrilepis Mas-Coma & Tenora, 1997 in arvicoline rodents from the greater Beringian region and western North America are described. Discovery and characterization of these tapeworms contributes to the recognition of a complex of cryptic species distributed across the Holarctic region. Three species are proposed: Arostrilepis gulyaevi sp. n. is named for cestodes in Myodes rufocanus from the Republic of Buryatia, southeastern Siberia and from the Khabarovskiy Kray, Chukotka Autonomous Okrug, and Magadanskaya Oblast', Russian Far East (western Beringia); A. cooki sp. n. is named for cestodes in Myodes gapperi from British Columbia, Canada and Montana, USA; and A. rauschorum sp. n. is named for cestodes in Microtus oeconomus, M. longicaudus, M. pennsylvanicus and M. xanthognathus from the Brooks Range, Seward Peninsula, north-central interior, and Arctic coastal plains of Alaska (eastern Beringia) and Montana, USA. Consistent with recent studies defining diversity in the genus, the form, size, and spination (pattern, shape and size) of the cirrus are diagnostic; species are further distinguished by the relative position and length of the cirrus sac, and arrangement of the testes. Assessment of genetic data from the cytochrome b gene of mitochondrial DNA complements differentiation of this complex based on morphological attributes and confirms known species diversity within the genus. New data for geographical distribution and host specificity of known Arostrilepis spp. indicate that 3 of 12 recognized species have Holarctic distributions extending across Beringia. These include Arostrilepis beringiensis (Kontrimavichus & Smirnova, 1991) in lemmings (species of Lemmus and Synaptomys), A. cf. janickii Makarikov & Kontrimavichus, 2011 in root voles (M. oeconomus) MAKARIKOV ET AL. 402 · Zootaxa 3608 (6) © 2013 Magnolia Press and A. macrocirrosa Makarikov, Gulyaev & Kontrimavichus, 2011 in red backed voles (species of Myodes) and less often other rodent host species.

  15. The valid generic name for red-backed voles (Muroidea: Cricetidae: Arvicolinae): restatement of the case for Myodes Pallas, 1811

    USGS Publications Warehouse

    Carleton, Michael D.; Gardner, Alfred L.; Pavlinov, Igor Ya.; Musser, Guy G.

    2014-01-01

    In view of contradictions in the recent literature, the valid genus-group name to be applied to northern red-backed voles—Myodes Pallas, 1811, or Clethrionomys Tilesius, 1850—is reviewed. To develop the thesis that Myodes (type species, Mus rutilus Pallas, 1779) is the correct name, our discussion explores the 19th-century taxonomic works that bear on the relevant taxa, the transition in zoological codes apropos the identification of type species, and past nomenclatural habits in cases where no type species was originally indicated. We conclude that Myodes is the senior name to use for the genus-group taxon that includes the Holarctic species rutilus and frame this conclusion within a synonymy of the genus.

  16. Diversity at the Holarctic nexus: species of Arostrilepis (Eucestoda: Hymenolepididae) in arvicoline rodents (Cricetidae: Arvicolinae) from greater Beringia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Previously unrecognized species of hymenolepidid cestodes attributable to Arostrilepis Mas-Coma & Tenora, 1997 in arvicoline rodents from the greater Beringian region and western North America are described. Discovery and characterization of these tapeworms contributes to the recognition of a compl...

  17. A Newly Emerged Cutaneous Leishmaniasis Focus in Northern Israel and Two New Reservoir Hosts of Leishmania major

    PubMed Central

    Faiman, Roy; Abbasi, Ibrahim; Jaffe, Charles; Motro, Yoav; Nasereddin, Abdelmagid; Schnur, Lionel F.; Torem, Moshe; Pratlong, Francine; Dedet, Jean-Pierre; Warburg, Alon

    2013-01-01

    In 2006/7, 18 cases of cutaneous leishmaniasis (CL) were reported for the first time from Sde Eliyahu (pop. 650), a village in the Beit She'an valley of Israel. Between 2007–2011, a further 88 CL cases were diagnosed bringing the total to 106 (16.3% of the population of Sde Eliyahu). The majority of cases resided in the south-western part of the village along the perimeter fence. The causative parasite was identified as Leishmania major Yakimoff & Schokhor, 1914 (Kinetoplastida: Trypanosomatidae). Phlebotomus papatasi (Scopoli), 1786 (Diptera: Psychodidae) was found to be the most abundant phlebotomine species comprising 97% of the sand flies trapped inside the village, and an average of 7.9% of the females were positive for Leishmania ITS1 DNA. Parasite isolates from CL cases and a sand fly were characterized using several methods and shown to be L. major. During a comprehensive survey of rodents 164 Levant voles Microtus guentheri Danford & Alston, 1880 (Rodentia: Cricetidae) were captured in alfalfa fields bordering the village. Of these 27 (16.5%) tested positive for Leishmania ITS1 DNA and shown to be L. major by reverse line blotting. A very high percentage (58.3% - 21/36) of Tristram's jirds Meriones tristrami Thomas, 1892 (Rodentia: Muridae), found further away from the village also tested positive for ITS1 by PCR. Isolates of L. major were successfully cultured from the ear of a wild jird found positive by ITS1 PCR. Although none of the wild PCR-positive voles exhibited external pathology, laboratory-reared voles that were infected by intradermal L. major inoculation, developed patent lesions and sand flies became infected by feeding on the ears of these laboratory-infected voles. This is the first report implicating M. guentheri and M. tristrami as reservoirs of Leishmania. The widespread co-distribution of M. guentheri and P. papatasi, suggests a significant threat from the spread of CL caused by L. major in the Middle East, central Asia and southern

  18. A glimpse on the pattern of rodent diversification: a phylogenetic approach

    PubMed Central

    2012-01-01

    Background Development of phylogenetic methods that do not rely on fossils for the study of evolutionary processes through time have revolutionized the field of evolutionary biology and resulted in an unprecedented expansion of our knowledge about the tree of life. These methods have helped to shed light on the macroevolution of many taxonomic groups such as the placentals (Mammalia). However, despite the increase of studies addressing the diversification patterns of organisms, no synthesis has addressed the case of the most diversified mammalian clade: the Rodentia. Results Here we present a rodent maximum likelihood phylogeny inferred from a molecular supermatrix. It is based on 11 mitochondrial and nuclear genes that covers 1,265 species, i.e., respectively 56% and 81% of the known specific and generic rodent diversity. The inferred topology recovered all Rodentia clades proposed by recent molecular works. A relaxed molecular clock dating approach provided a time framework for speciation events. We found that the Myomorpha clade shows a greater degree of variation in diversification rates than Sciuroidea, Caviomorpha, Castorimorpha and Anomaluromorpha. We identified a number of shifts in diversification rates within the major clades: two in Castorimorpha, three in Ctenohystrica, 6 within the squirrel-related clade and 24 in the Myomorpha clade. The majority of these shifts occurred within the most recent familial rodent radiations: the Cricetidae and Muridae clades. Using the topological imbalances and the time line we discuss the potential role of different diversification factors that might have shaped the rodents radiation. Conclusions The present glimpse on the diversification pattern of rodents can be used for further comparative meta-analyses. Muroid lineages have a greater degree of variation in their diversification rates than any other rodent group. Different topological signatures suggest distinct diversification processes among rodent lineages. In

  19. Localized versus generalist phenotypes in a broadly distributed tropical mammal: how is intraspecific variation distributed across disparate environments?

    PubMed Central

    2013-01-01

    Background The extent of phenotypic differentiation in response to local environmental conditions is a key component of species adaptation and persistence. Understanding the structuring of phenotypic diversity in response to local environmental pressures can provide important insights into species evolutionary dynamics and responses to environmental change. This work examines the influence of steep environmental gradients on intraspecific phenotypic variation and tests two hypotheses about how the tropical soft grass mouse, Akodon mollis (Cricetidae, Rodentia), contends with the disparate environmental conditions encompassed by its broad distribution. Specifically, we test if the species expresses a geographically unstructured, or generalist, phenotype throughout its range or if it shows geographically localized morphological differentiation across disparate environments. Results Using geometric morphometric and ecomorphological analyses of skull shape variation we found that despite distinct environmental conditions, geographically structured morphological variation is limited, with the notable exception of a distinct morphological disjunction at the high-elevation forest-grassland transition in the southern portion of A. mollis distribution. Based on genetic analyses, geographic isolation alone does not explain this localized phenotype, given that similar levels of genetic differentiation were also observed among individuals inhabiting other ecosystems that are nonetheless not distinct morphologically. Conclusions Instead of phenotypic specialization across environments in these tropical mountains, there was limited differentiation of skull shape and size across the broad range of A. mollis, with the exception of individuals from the puna, the highest-elevation ecosystem. The high morphological variance among individuals, together with a weak association with local environmental conditions, not only highlights the flexibility of A. mollis’ skull, but also

  20. A widespread distribution for Arostrilepis tenuicirrosa (Eucestoda: Hymenolepididae) in Myodes voles (Cricetidae: Arvicolinae) from the Palearctic based on molecular and morphological evidence: historical and biogeographic implications.

    PubMed

    Galbreath, Kurt E; Ragaliauskaite, Kristina; Kontrimavichus, Leonas; Makarikov, Arseny A; Hoberg, Eric P

    2013-12-01

    Hymenolepidid cestodes in Myodes glareolus from Lithuania and additional specimens originally attributed to Arostrilepis horrida from the Republic of Belarus are now referred to A. tenuicirrosa. Our study includes the first records of A. tenuicirrosa from the European (western) region of the Palearctic, and contributes to the recognition of A. horrida (sensu lato) as a complex of cryptic species distributed broadly across the Holarctic. Specimens of A. tenuicirrosa from Lithuania were compared to cestodes representing apparently disjunct populations in the eastern Palearctic based on structural characters of adult parasites and molecular sequence data from nuclear (ITS2) and mitochondrial (cytochrome b) genes. Morphological and molecular data revealed low levels of divergence between eastern and western populations. Phylogeographic relationships among populations and host biogeographic history suggests that limited intraspecific diversity within A. tenuicirrosa may reflect a Late Pleistocene transcontinental range expansion from an East Asian point of origin.

  1. DNA sequence analysis and the phylogeographical history of the rodent Deltamys kempi (Sigmodontinae, Cricetidae) on the Atlantic Coastal Plain of south of Brazil.

    PubMed

    Montes, M A; Oliveira, L F B; Bonatto, S L; Callegari-Jacques, S M; Mattevi, M S

    2008-11-01

    The rodent Deltamys kempiThomas, 1917 is found on the Coastal Plain - a recently formed geographic region located on Brazil's south-east coast. Considering that Deltamys is the only South American sigmodontine with a sex chromosome system of type X(1)X(1)X(2)X(2)/X(1)X(2)Y, this investigation was focused on the phylogeographic history of this taxon by using gene sequence analysis, trying to clarify when Deltamys differentiated, what was its centre of diversification, and what were the probable routes it used to reach its present distribution. We analysed sequences of the mitochondrial cytochrome b gene and nuclear recombination activating gene 2, performed cranial measurements and searched for centric fusions in individuals collected in distinct localities. The results, clearly demonstrate that D. kempi, on the Coastal Plain, divided into two groups, one occupying a small portion to the north of this region and the other spreading widely to the south. In this process, the phenomena of marine transgression and regressions which moulded its habitat, together with the occurrence of successive chromosomal rearrangements, were certainly the fundamental factors in shaping D. kempi diversification.

  2. Molecular phylogenetic position of endangered Wilfredomys within Sigmodontinae (Cricetidae) based on mitochondrial and nuclear DNA sequences and comments on Wiedomyini.

    PubMed

    Machado, Leonardo Ferreira; Passaia, Milena Henrique; Rodrigues, Fernando Pacheco; Peters, Felipe Bortolotto; Sponchiado, Jonas; Valiati, Victor Hugo; Christoff, Alexandre Uarth

    2015-07-20

    Wilfredomys, a monotypic genus of endangered sigmodontine rats, was historically related to the tribe Thomasomyini or considered "incertae sedis". Given no molecular data is available for Wilfredomys, the phylogenetic position of this taxon is uncertain in relation to modern, molecular hypotheses of sigmodontine relationships. We investigate the phylogeny of Wilfredomys to provide a hypothesis of its position within Sigmodontinae based on nuclear and mitochondrial DNA sequences. Bayesian and maximum likelihood phylogenetic analyses recovered Wilfredomys oenax as sister to Wiedomys pyrrhorhinos, and Wie. cerradensis fell out sister to this clade. At the genus level, Phaenomys is sister to Wilfredomys + Wiedomys, forming a novel and well-supported sigmodontine clade. Our results suggest that tribe Wiedomyini should encompass Wilfredomys in addition to Wiedomys and Cholomys, thus the hypothesis that Wiedomys is paraphyletic should be investigated further. Another plausible classification scheme consistent with our results would be to expand Wiedomyini to encompass the clade composed of Phaenomys + Wilfredomys + Wiedomys. Last, our recovery of an "Atlantic clade" composed of lineages restricted to eastern South America supports the idea that this region has likely played an important role in sigmodontine diversification.

  3. A widespread distribution for Arostrilepis tenuicirrosa (Eucestoda: Hymenolepididae) among arvicoline rodent hosts (Cricetidae) from the Palearctic based on molecular and morphological criteria: Historical and biogeographic

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hymenolepidid cestodes in Myodes glareolus from Lithuania and additional specimens originally attributed to Arostrilepis horrida from the Republic of Belarus are now referred to A. tenuicirrosa. Our study includes the first records of A. tenuicirrosa from the European (western) region of the Palearc...

  4. A review of Gongylonema spp. (Nematoda: Gongylonematidae) in North American rodents with description of a new species from the cotton rat, Sigmodon hispidus (Mammalia: Cricetidae).

    PubMed

    Kinsella, John M; Robles, Maria Del Rosario; Preisser, Whitney C

    2016-05-02

    Gongylonema archboldi n. sp. (Nematoda: Gongylonematidae) is described from tunnels in the gastric mucosa of the stomach of the cotton rat (Sigmodon hispidus) from Highlands County, Florida, U.S.A. Measurements are also given for specimens from cotton mice (Peromyscus gossypinus), oldfield mice (Peromyscus polionotus), Florida mice (Podomys floridanus), and golden mice (Ochrotomys nuttalli) from the same locality. Additional specimens were collected from the cotton rat and the rice rat (Oryzomys palustris) from Berry Island, San Patricio County, Texas. The new species is differentiated from congeners by a combination of the following characters: length of the left spicule, length and shape of the gubernaculum, distribution of cuticular bosses, length of esophagus, and distance of the vulva from the posterior end. The status of the genus Gongylonema in North American rodents is reviewed.

  5. A new flea of the genus Ctenidiosomus (Siphonaptera, Pygiopsyllidae) from Salta Province, Argentina

    PubMed Central

    López-Berrizbeitia, M. Fernanda; Hastriter, Michael W.; Barquez, Rubén M.; Díaz, M. Mónica

    2015-01-01

    Abstract A new species of flea of the genus Ctenidiosomus Jordan, 1931 (Siphonaptera: Pygiopsyllidae) is described from Phyllotis osilae J. A. Allen, 1901, from Salta Province, Argentina. This is the first time that Ctenidiosomus has been recorded in Argentina. A key to species of males of Ctenidiosomus is presented. PMID:26257563

  6. The origin of an unusual sex chromosome constitution in Acomys sp. (Rodentia, Muridae) from Tanzania.

    PubMed

    Castiglia, Riccardo; Makundi, Rhodes; Corti, Marco

    2007-10-01

    This paper describes a case which presents an evident variation from the "standard" XX/XY sex chromosomal constitution in a rodent, Acomys sp. This species known to be found in three localities of East Africa has only recently been separated from A. spinosissimus, its closest relative. In our study, five specimens of Acomys sp. and eight specimens of A. spinosissimus were live-trapped in five localities. Comparisons between the two taxa assed by G-banding show a complete homology in the chromosomal shape and banding pattern for 29 pairs of chromosomes corresponding to the complete autosomal set of A. spinosissimus. However, while all the A. spinosissimus analysed have 2n = 60 and a XY-XX system, in Acomys sp. males and females constitute mosaics for sex chromosomes in the bone marrow cells. Females (2n = 59, 60) have an excess (97%) of aneuploid cells with one single giant X chromosome, and males (2n = 60, 61) show X0/XY cells occurring in somatic tissues and XY cells in the germinal lineage. In addition, an odd heterochromatic submetacentric chromosome was identified in all the cells examined in two males and a female of Acomys sp. Since this chromosome was not related to sex determination and it is not present in all the analysed specimens, it can be considered as a B chromosome. Finally, the in situ fluorescence hybridisation (FISH) with telomeric probes showed a very intense interstitial telomeric signal (ITS) at the medial part on the long heterochromatic arm of the X chromosome. This could be due to recent chromosomal rearrangement.

  7. Intrageneric phylogeny of Acomys (rodentia, muridae) using mitochondrial gene cytochrome b.

    PubMed

    Barome, P O; Monnerot, M; Gautun, J C

    1998-06-01

    This paper investigates interspecies relationships within the genus Acomys (spiny mice) by analyzing entire mitochondrial cytochrome b gene (1141 bp). This gene provides strong phylogenetic signal, as shown by high support of the topology obtained (bootstrap value and RNA support number). The phylogeny is congruent with inferences from allozymes for the species considered. Controversial taxonomy of Acomys cahirinus, dimidiatus, airensis, and ignitus is clarified, with their specific ranks confirmed on the basis of tree topology and nucleotide distances. Phylogenetic relationship between the undescribed species Acomys sp. from west Africa and A. airensis argue in favor of two distinct colonization events in this zone.

  8. Ear Structures of the Naked Mole-Rat, Heterocephalus glaber, and Its Relatives (Rodentia: Bathyergidae)

    PubMed Central

    Mason, Matthew J.; Cornwall, Hannah L.; Smith, Ewan St. J.

    2016-01-01

    Although increasingly popular as a laboratory species, very little is known about the peripheral auditory system of the naked mole-rat, Heterocephalus glaber. In this study, middle and inner ears of naked mole-rats of a range of ages were examined using micro-computed tomography and dissection. The ears of five other bathyergid species (Bathyergus suillus, Cryptomys hottentotus, Fukomys micklemi, Georychus capensis and Heliophobius argenteocinereus) were examined for comparative purposes. The middle ears of bathyergids show features commonly found in other members of the Ctenohystrica rodent clade, including a fused malleus and incus, a synovial stapedio-vestibular articulation and the loss of the stapedius muscle. Heterocephalus deviates morphologically from the other bathyergids examined in that it has a more complex mastoid cavity structure, poorly-ossified processes of the malleus and incus, a ‘columelliform’ stapes and fewer cochlear turns. Bathyergids have semicircular canals with unusually wide diameters relative to their radii of curvature. How the lateral semicircular canal reaches the vestibule differs between species. Heterocephalus has much more limited high-frequency hearing than would be predicted from its small ear structures. The spongy bone forming its ossicular processes, the weak incudo-stapedial articulation, the columelliform stapes and (compared to other bathyergids) reduced cochlear coiling are all potentially degenerate features which might reflect a lack of selective pressure on its peripheral auditory system. Substantial intraspecific differences were found in certain middle and inner ear structures, which might also result from relaxed selective pressures. However, such interpretations must be treated with caution in the absence of experimental evidence. PMID:27926945

  9. Morphological modularity and assessment of developmental processes within the vole dental row (Microtus arvalis, Arvicolinae, Rodentia).

    PubMed

    Laffont, Rémi; Renvoisé, Elodie; Navarro, Nicolas; Alibert, Paul; Montuire, Sophie

    2009-01-01

    Knowledge of mammalian tooth formation is increasing, through numerous genetic and developmental studies. The prevalence of teeth in fossil remains has led to an intensive description of evolutionary patterns within and among lineages based on tooth morphology. The extent to which developmental processes have influenced tooth morphologies and therefore the role of these processes in these evolutionary patterns are nonetheless challenging. Recent methodological advances have been proposed allowing the inference of developmental processes from adult morphologies and the characterization of the degree of developmental integration/modularity of morphological traits by studying the patterns of variation within and among individuals. This study focuses on the geometric shape of the lower molars of the vole species Microtus arvalis. Our results suggest (i) quasi-independence of each molar at the developmental level (developmental modules), even slightly stronger for the third molar supporting some genetic and developmental hypotheses and (ii) more pervasive integration processes among molars at the morphological level.

  10. Ontogenetic and evolutionary trends in the tooth enamel features in Craseomys voles (Arvicolinae, Rodentia).

    PubMed

    Fominykh, M A; Zykov, S V; Borodin, A V

    2016-11-01

    In Craseomys rufocanus and Craseomys rex, the age-related and species differences in thickness and microstructure of the first lower molars (ml) have been identified and studied. The results suggest that the enamel dimensional and microstructural features may serve as additional indicators of the vole tooth evolutionary stage within a single phyletic lineage.

  11. Sequence analysis and mapping of the Sry gene in species of the subfamily Arvicolinae (rodentia).

    PubMed

    Acosta, M J; Marchal, J A; Romero-Fernández, I; Megías-Nogales, B; Modi, W S; Sánchez Baca, Antonio

    2010-01-01

    The rodent subfamily Arvicolinae, which contains about 125 species, presents some interesting exceptions concerning Sry, the sex determining gene in mammals. In some species multiple Sry copies have been described on the Y chromosome and in the Iberian vole, Microtus cabrerae, several Sry sequences have been cloned and mapped not only on the Y but also on the X chromosome. Here we present a comparative analysis of Sry sequences from a total of 22 species. Our study demonstrates for the first time that for most North American species, as previously reported for the European species, multiple copies of the Sry gene exist on the Y chromosome. Furthermore, we have sequenced and analyzed the full sequence of Sry from several European species, showing that the sequence and structure of the gene in this group of species present the main features described for Sry in other mammals. Finally, FISH analyses on some of these species demonstrated that all Sry sequences, despite their functional status, mapped on the euchromatic short arm of the Y chromosome.

  12. Phylogeny of Oriental voles (Rodentia: Muridae: Arvicolinae): molecular and morphological evidence.

    PubMed

    Liu, Shaoying; Liu, Yang; Guo, Peng; Sun, Zhiyu; Murphy, Robert W; Fan, Zhenxin; Fu, Jianrong; Zhang, Yaping

    2012-09-01

    The systematics of Oriental voles remains controversial despite numerous previous studies. In this study, we explore the systematics of all species of Oriental voles, except Eothenomys wardi, using a combination of DNA sequences and morphological data. Our molecular phylogeny, based on two mitochondrial genes (COI and cyt b), resolves the Oriental voles as a monophyletic group with strong support. Four distinct lineages are resolved: Eothenomys, Anteliomys, Caryomys, and the new subgenus Ermites. Based on morphology, we consider Caryomys and Eothenomys to be valid genera. Eothenomys, Anteliomys, and Ermites are subgenera of Eothenomys. The molecular phylogeny resolves subgenera Anteliomys and Ermites as sister taxa. Subgenus Eothenomys is sister to the clade Anteliomys + Ermites. Caryomys is the sister group to genus Eothenomys. Further, the subspecies E. custos hintoni and E. chinensis tarquinius do not cluster with E. custos custos and E. chinensis chinensis, respectively, and the former two taxa are elevated to species level and assigned to the new subgenus Ermites.

  13. Sequencing and analysis of complete mitochondrial genome of Apodemus draco (Rodentia: Arvicolinae).

    PubMed

    Wei, Haixue; Jia, Qiang; Li, Fengjun; Liu, Yongcheng; Chen, Shunde; Yong, Bin

    2015-08-14

    The genus Apodemus are the most common small rodents in fields. They are also one of the best species for biogeographic study and understanding the environmental changes. In this study, the complete mitochondrial genome sequence of Apodemus draco is determined. The mitogenome is 16 220 bp in length and contains 13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNA genes and a control region, with a base composition of 35.1% A, 29.0% T, 23.8% C and 12.1% G. The nucleotide sequence data of 12 heavy-strand protein-coding genes of Apodemus draco and other 23 rodents were used for mitochondrial genome phylogenetic analyses. The monophyly of the genus Apodemus was well supported with sister to the genus Mus. Bayesian analysis also suggested that Apodemus draco was a sister to Apodemus latronum. The present study may facilitate further investigation of the molecular evolution and biogeographic study of the genus Apodemus.

  14. Molecular phylogeny of the speciose vole genus Microtus (Arvicolinae, Rodentia) inferred from mitochondrial DNA sequences.

    PubMed

    Jaarola, Maarit; Martínková, Natália; Gündüz, Islam; Brunhoff, Cecilia; Zima, Jan; Nadachowski, Adam; Amori, Giovanni; Bulatova, Nina S; Chondropoulos, Basil; Fraguedakis-Tsolis, Stella; González-Esteban, Jorge; José López-Fuster, María; Kandaurov, Andrei S; Kefelioğlu, Haluk; da Luz Mathias, Maria; Villate, Idoia; Searle, Jeremy B

    2004-12-01

    Voles of the genus Microtus represent one of the most speciose mammalian genera in the Holarctic. We established a molecular phylogeny for Microtus to resolve contentious issues of systematic relationships and evolutionary history in this genus. A total of 81 specimens representing ten Microtus species endemic to Europe as well as eight Eurasian, six Asian and one Holarctic species were sequenced for the entire cytochrome b gene (1140 bp). A further 25 sequences were retrieved from GenBank, providing data on an additional 23, mainly Nearctic, Microtus species. Phylogenetic analysis of these 48 species generated four well-supported monophyletic lineages. The genus Chionomys, snow voles, formed a distinct and well-supported lineage separate from the genus Microtus. The subgenus Microtus formed the strongest supported lineage with two sublineages displaying a close relationship between the arvalis species group (common voles) and the socialis species group (social voles). Monophyly of the Palearctic pitymyid voles, subgenus Terricola, was supported, and this subgenus was also subdivided into two monophyletic species groups. Together, these groupings clarify long-standing taxonomic uncertainties in Microtus. In addition, the "Asian" and the Nearctic lineages reported previously were identified although the latter group was not supported. However, relationships among the main Microtus branches were not resolved, suggesting a rapid and potentially simultaneous radiation of a widespread ancestor early in the history of the genus. This and subsequent radiations discernible in the cytochrome b phylogeny, show the considerable potential of Microtus for analysis of historical and ecological determinants of speciation in small mammals. It is evident that speciation is an ongoing process in the genus and that the molecular data provides a vital insight into current species limits as well as cladogenic events of the past.

  15. Sequencing and analysis of complete mitochondrial genome of Apodemus draco (Rodentia: Arvicolinae).

    PubMed

    Wei, Haixue; Jia, Qiang; Li, Fengjun; Liu, Yongcheng; Chen, Shunde; Yong, Bin

    2016-07-01

    The genus Apodemus are the most common small rodents in fields. They are also one of the best species for biogeographic study and understanding the environmental changes. In this study, the complete mitochondrial genome sequence of Apodemus draco is determined. The mitogenome is 16 220 bp in length and contains 13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNA genes and a control region, with a base composition of 35.1% A, 29.0% T, 23.8% C and 12.1% G. The nucleotide sequence data of 12 heavy-strand protein-coding genes of Apodemus draco and other 23 rodents were used for mitochondrial genome phylogenetic analyses. The monophyly of the genus Apodemus was well supported with sister to the genus Mus. Bayesian analysis also suggested that Apodemus draco was a sister to Apodemus latronum. The present study may facilitate further investigation of the molecular evolution and biogeographic study of the genus Apodemus.

  16. The complete mitochondrial genome of the bank vole Clethrionomys glareolus (Rodentia: Arvicolinae).

    PubMed

    Bendová, Karolína; Marková, Silvia; Searle, Jeremy B; Kotlík, Petr

    2016-01-01

    We present the first complete sequence of the bank vole (Clethrionomys glareolus) mitochondrial genome (GenBank accession no. KF918859). The bank vole mitogenome is 16,353 base pairs long and shows the gene content, genome architecture and gene strand asymmetry typical for mammals. The sequence provides an important new genomic resource for the bank vole, which is a popular study species in ecological and evolutionary research.

  17. Characterization of the satellite DNA Msat-160 from the species Chionomys nivalis (Rodentia, Arvicolinae).

    PubMed

    Acosta, M J; Marchal, J A; Martínez, S; Puerma, E; Bullejos, M; la de Guardia, R Díaz; Sánchez, A

    2007-05-01

    The satellite DNA Msat-160 has been previously characterized in several species of the genus Microtus. Here we present the characterization of Msat-160 from Chionomys nivalis, a species with a very primitive karyotype. As in other Microtus species analyzed, C. nivalis Msat-160 is AT rich, has a monomer length of 160 bp, is undermethylated and is mainly located in all the pericentromeric heterochromatin of all autosomes and the X chromosome, but is completely absent from the Y chromosome. Hence, our results support the hypothesis that Msat-160 was initially distributed in the pericentromeric heterochromatin of all autosomes and the X chromosome. The taxonomic status of the genus Chionomys in relation to the genus Microtus is a very interesting issue, so we constructed phylogenetic dendrograms using Msat-160 sequences from several Microtus species. Although the results were not informative about this issue, the presence of Msat-160 in C. nivalis and Microtus species suggested that both genera are closely related and that this satellite DNA was present in the common ancestor. Studies of Msat-160 in different arvicoline species could help to determine the origin of this satellite and, perhaps, to establish the phylogenetic relationships of some arvicoline groups.

  18. [Meiosis in gray voles of the subgenus microtus (rodentia, arvicolinae) and in their hybrids].

    PubMed

    Safronova, L D; Golenishchev, F N; Cherepanova, E V; Baskevich, M I

    2011-07-01

    The results of light and electron microscopic (EM) studies of meiosis in Microtus arvalis males of the karyoform "arvalis" (2n = 46, NFa = 80), in hybrids between the chromosomal forms arvalis and obscurus (2n = 46, NFa = 68), in M. rossiaemeridionalis voles (2n = 54, NFa = 54), and in a hybrid between the species M. rossiaemeridionalis and M. kermanensis (2n = 54, NFa = 54) are presented. SC (synaptonemal complex) karyotypes of the parental forms and the hybrids were constructed on the basis of measurements of the length ofautosomal SCs revealed by the EM analysis in spermatocytes at the stage of middle pachytene. The SC karyotypes of M. arvalis and the hybrids female obscurus x male arvalis consist of 22 synaptonemal complexes of autosomal bivalents and the axial elements of the synaptonemal complexes of the sex chromosomes X and Y. The SC karyotypes of M. rossiaemeridionalis and the hybrid M. rossiaemeridionalis x M. kermanensis consist of 26 synaptonemal complexes of autosomal bivalents and a sex bivalent; they differ only in the length of the Y chromosome axis (Y chromosome in the hybrid was inherited from M. kermanensis). Asynaptic configurations of the autosomal SCs were not observed in the hybrids. The SC axial elements of the X and Y chromosomes in the parental forms and in the hybrids were located close to each other throughout pachytene, but they did not form a synaptic region. The normal synapsis in sterile hybrids (M. rossiaemeridionalis x M. kermanensis) and the behavior of the sex chromosomes in meiosis in fertile and sterile hybrids are discussed in the context of specific features of meiosis and reproductive isolation.

  19. Clues on Syntenic Relationship among Some Species of Oryzomyini and Akodontini Tribes (Rodentia: Sigmodontinae)

    PubMed Central

    Suárez, Pablo; Nagamachi, Cleusa Yoshiko; Lanzone, Cecilia; Malleret, Matias Maximiliano; O’Brien, Patricia Caroline Mary; Ferguson-Smith, Malcolm Andrew; Pieczarka, Julio Cesar

    2015-01-01

    Sigmodontinae rodents represent one of the most diverse and complex components of the mammalian fauna of South America. Among them most species belongs to Oryzomyini and Akodontini tribes. The highly specific diversification observed in both tribes is characterized by diploid complements, which vary from 2n = 10 to 86. Given this diversity, a consistent hypothesis about the origin and evolution of chromosomes depends on the correct establishment of synteny analyzed in a suitable phylogenetic framework. The chromosome painting technique has been particularly useful for identifying chromosomal synteny. In order to extend our knowledge of the homeological relationships between Akodontini and Oryzomyini species, we analyzed the species Akodon montensis (2n = 24) and Thaptomys nigrita (2n = 52) both from the tribe Akodontini, with chromosome probes of Hylaeamys megacephalus (2n = 54) of the tribe Oryzomyini. The results indicate that at least 12 of the 26 autosomes of H. megacephalus show conserved synteny in A. montensis and 14 in T. nigrita. The karyotype of Akodon montensis, as well as some species of the Akodon cursor species group, results from many chromosomal fusions and therefore the syntenic associations observed probably represent synapomorphies. Our finding of a set of such associations revealed by H. megacephalus chromosome probes (6/21; 3/25; 11/16/17; and, 14/19) provides phylogenetic information for both tribes. An extension of these observations to other members of Akodontini and Oryzomyini tribes should improve our knowledge about chromosome evolution in both these groups. PMID:26642204

  20. Sequence and phylogenetic analysis of the complete mitochondrial genome of Lasiopodomys mandarinus mandarinus (Arvicolinae, Rodentia).

    PubMed

    Li, Yangwei; Shi, Yuhua; Lu, Jiqi; Ji, Weihong; Wang, Zhenlong

    2016-11-30

    Mandarin vole (Lasiopodomys mandarinus) is a subterranean rodent that is often used as a model for studying subterranean hypoxic stress in mammals. However the taxonomy of this species is still in dispute. Mitochondrial DNA (mtDNA) has long been used for phylogenetic reconstruction and, in this study, the complete mitochondrial genome of L. mandarinus mandarinus was sequenced. Our results showed that the mitochondrial genome of L. m. mandarinus is a circular molecule of 16,367bp, which contains 13 protein-coding genes, 22 tRNA and 2 rRNA genes. Except for the 8 tRNA and ND6 genes, all other mitochondrial genes are encoded on the heavy strand. We also analyzed the phylogenetic position of L. mandarinus in respect to the tribe Arvicolini using the sequence of complete Cytb gene, 2rRNA genes and 12 protein-coding genes, and maximum likelihood and Bayesian methods. Our results gave further support to the species status of L. mandarinus and the generic status of Lasiopodomys.

  1. Multilocus systematics and non-punctuated evolution of Holarctic Myodini (Rodentia: Arvicolinae).

    PubMed

    Kohli, Brooks A; Speer, Kelly A; Kilpatrick, C William; Batsaikhan, Nyamsuren; Damdinbazar, Darmaa; Damdinbaza, Darmaa; Cook, Joseph A

    2014-07-01

    The tribe Myodini consists of five genera of forest and alpine voles (Alticola, Caryomys, Eothenomys, Hyperacrius and Myodes) distributed throughout the Holarctic. Because mitochondrial evidence has revealed paraphyly and polyphyly among genera, we apply the first multilocus tests to clarify taxonomy and phylogenetic relationships. Our analyses of 28 of 36 species within Myodini, including three not previously sequenced (A. montosa, A. albicaudus, and H. fertilis), identify four distinct clades and provide the first molecular evidence that Hyperacrius may not belong in Myodini. Myodes is paraphyletic, while polyphyly of Alticola reflects apparent ancient mitochondrial introgression. Diversification in this tribe was hypothesized to be tightly linked to Late Cenozoic climatic events, however, lineage through time analysis indicates diversification over the last 4 My was gradual and not strongly punctuated.

  2. Complete mitochondrial genome of the Chinese oriental vole Eothenomys chinensis (Rodentia: Arvicolinae).

    PubMed

    Yang, Chengzhong; Hao, Haibang; Liu, Shaoying; Liu, Yang; Yue, Bisong; Zhang, Xiuyue

    2012-04-01

    The Chinese oriental vole (Eothenomys chinensis) belongs to subfamily Arvicolinae, which is endemic to the mountains in southwest China. E. chinensis and other Arvicoline species display a number of features that make them ideal for evolutionary studies of speciation and the role of Quaternary glacial cycles on diversification. In this study, the complete mitochondrial genome of E. chinensis was sequenced. It was determined to be 16,362 bases. The nucleotide sequence data of 12 heavy-strand protein-coding genes of E. chinensis and other 19 rodents were used for phylogenetic analyses. Trees constructed using three different phylogenetic methods (Bayesian, maximum parsimony, and maximum likelihood) showed a similar topology demonstrating that E. chinensis was clustered in subfamily arvicolinae--formed a solid monophyletic group being sister to the subfamily Cricetinae. And the trees also suggested that E. chinensis is a sister to the genus Microtus and Proedromys.

  3. Complete mitochondrial genome of the Père David's Vole, Eothenomys melanogaster (Rodentia: Arvicolinae).

    PubMed

    Chen, Shunde; Chen, Guiying; Wei, Haixue; Wang, Qiong

    2016-07-01

    The Père David's Vole, Eothenomys melanogaster belongs to subfamily Arvicolinae. It is widespread in south China, and ranges into northern Southeast Asia. In this study, the complete mitochondrial genome sequence of Eothenomys melanogaster was determined. The mitogenome is 16,331 base pairs in length. The nucleotide sequence data of 12 heavy-strand protein-coding genes of E. melanogaster and other 17 rodents were used for phylogenetic analyses. Tree constructed using Bayesian phylogenetic methods demonstrated that E. melanogaster as a sister to E. chinensis, was clustered in subfamily Arvicolinae. The monophyly of the genus Eothenomys was supported as well with Eothenomys sister to the genus Myodes.

  4. Morphological Chronoclines among Late Pleistocene Muskrats ( Ondatra zibethicus: Muridae, Rodentia) from Northern Florida

    NASA Astrophysics Data System (ADS)

    Mihlbachler, Matthew C.; Hemmings, C. Andrew; Webb, S. David

    2002-11-01

    The muskrat ( Ondatra zibethicus) is presumed to have undergone a rapid phyletic size decrease near the end of the Pleistocene. Evolutionary changes in the size of middle to late Wisconsinan (ca. 32,000-12,300 14C yr B.P.) muskrats from the Aucilla River, Jefferson County, Florida, were reconstructed by examining length and width of the lower first molar (m1). Body mass, estimated from m1 length, was relatively stable from 32,000 to 16,000 14C yr B.P. and decreased only slightly by 12,300 14C yr B.P. If the size trend found in the Aucilla River material is characteristic of the southeastern United States, a body size decrease after 12,300 14C yr B.P. is needed to explain the smaller size of modern populations. It was previously thought that the length/width (l/w) ratio of the muskrat m1 was a paleoenvironmental indicator based on its presumed correlation with latitude in modern populations. We examined the length and width of modern muskrats from several geographic regions and found only a very weak trend in the size of the m1 between northern and southern populations; however, highly significant differences were found between regions of similar latitude. Our data indicate that chronoclines in the m1 of the Aucilla muskrat material and other such documented trends among fossil muskrats have paleoenvironmental significance, but it is not yet clear which environmental variables can best be predicted from them.

  5. Phylogenetic and environmental components of morphological variation: skull, mandible, and molar shape in marmots (Marmota, Rodentia).

    PubMed

    Caumul, Radhekshmi; Polly, P David

    2005-11-01

    The phenotype is a product of its phylogenetic history and its recent adaptation to local environments, but the relative importance of the two factors is controversial. We assessed the effects of diet, habitat, elevation, temperature, precipitation, body size, and mtDNA genetic divergence on shape variation in skulls, mandibles, and molars, structures that differ in their genetic and functional control. We asked whether these structures have adapted to environment to the same extent and whether they retain the same amount of phylogenetic signal. We studied these traits in intra- and interspecific populations of Eurasian marmots whose last common ancestor lived 2-5 million years ago. Path Analysis revealed that body size explained 10% of variation in skulls, 7% in mandibles, and 15% in molars. Local vegetation explained 7% of variation in skulls, 11% in mandibles, and 12% in molars. Dietary category explained 25% of variation in skulls, 11% in mandibles, and 9% in molars. Cyt b mtDNA divergence (phylogeny) explained 15% of variation in skulls, 7% in mandibles, and 5% in molars. Despite the percentages of phylogenetic variance, maximum-likelihood trees based on molar and skull shape recovered most phylogenetic groupings correctly, but mandible shape did not. The good performance of molars and skulls was probably due to different factors. Skulls are genetically and functionally more complicated than teeth, and they had more mathematically independent components of variation (5-6-in skulls compared to 3-in molars). The high proportion of diet-related variance was not enough to mask the phylogenetic signal. Molars had fewer independent components, but they also have less ecophenotypic variation and evolve more slowly, giving each component a proportionally stronger phylogenetic signal. Molars require larger samples for each operational taxonomic unit than the other structures because the proportion of within-taxon to between-taxon variation was higher. Good phylogenetic signal in quantitative skeletal morphology is likely to be found only when the taxa have a common ancestry no older than hundreds of thousands or millions of years (1% to 10% mtDNA divergence)--under these conditions skulls and molars provide stronger signal than mandibles.

  6. First Miocene rodent from Lebanon provides the 'missing link' between Asian and African gundis (Rodentia: Ctenodactylidae)

    PubMed Central

    López-Antoñanzas, Raquel; Knoll, Fabien; Maksoud, Sibelle; Azar, Dany

    2015-01-01

    Ctenodactylinae (gundis) is a clade of rodents that experienced, in Miocene time, their greatest diversification and widest distribution. They expanded from the Far East, their area of origin, to Africa, which they entered from what would become the Arabian Peninsula. Questions concerning the origin of African Ctenodactylinae persist essentially because of a poor fossil record from the Miocene of Afro-Arabia. However, recent excavations in the Late Miocene of Lebanon have yielded a key taxon for our understanding of these issues. Proafricanomys libanensis nov. gen. nov. sp. shares a variety of dental characters with both the most primitive and derived members of the subfamily. A cladistic analysis demonstrates that this species is the sister taxon to a clade encompassing all but one of the African ctenodactylines, plus a southern European species of obvious African extraction. As such, Proafricanomys provides the 'missing link' between the Asian and African gundis. PMID:26250050

  7. Unique Regulation of the Melatonin Synthetic Pathway in the Retina of Diurnal Female Arvicanthis ansorgei (Rodentia).

    PubMed

    Gianesini, Coralie; Clesse, Daniel; Tosini, Gianluca; Hicks, David; Laurent, Virginie

    2015-09-01

    Knowledge about melatonin synthesis and its potential roles within the retina remains fragmented, especially in mammals where studies have focused on the penultimate enzyme of melatonin synthesis arylalkylamine N-acetyltransferase (AA-NAT), whereas the final enzyme necessary for melatonin production is hydroxyindole-O-methytransferase (HIOMT). We explored multiple parameters of the melatonin synthetic pathway in the cone-rich retina of a diurnal rodent, Arvicanthis ansorgei, cones being previously implicated as probable reservoirs of melatonin production. We analyzed the temporal and spatial expression of Aa-nat mRNA and AA-NAT protein and enzymatic activity of AA-NAT, HIOMT, as well as the melatonin receptor type 1 and melatonin itself. We report that Aa-nat mRNA was localized principally to cones and ganglion cells (retinal ganglion cell [RGC]) with opposing cyclic expression, being maximal in cones during the night, and maximal in RGC in the daytime. AA-NAT protein was also immunolocalized to these same populations, and was present and active throughout the 24-hour period. HIOMT immunolocalization mirrored that of AA-NAT, but expression levels and activity were extremely low and remained uniform throughout the 24-hour period. MT1 showed a complementary expression pattern to the synthetic enzymes, present in rod photoreceptors, some inner retinal neurons and RGC. Surprisingly, melatonin levels were consistently low throughout the day/night cycle, in accordance with the low activity levels of HIOMT. These data demonstrate that the melatonin synthetic pathway in a diurnal rodent differs from that described for other tissues and species (nocturnal and diurnal), the contrasting phase expression in photoreceptors and RGC, suggesting distinct roles in these populations.

  8. Two new species of Hymenolepis (Cestoda: Hymenolepididae) from Spalacidae and Muridae (Rodentia) from eastern Palearctic.

    PubMed

    Makarikov, Arseny A; Tkach, Vasyl V

    2013-03-01

    Previously unrecognized species of the genus Hymenolepis are described based on specimens from spalacid and murid (Murinae) rodents. Hymenolepis rymzhanovi sp. nov. from the Siberian zokor, Myospalax myospalax (Laxmann), from East Kazakhstan, and H. apodemi sp. nov. from Eurasian field mice, Apodemus peninsulae (Thomas), A. uralensis (Pallas) and A. agrarius (Pallas), from the south of Russian Far East, western Siberia and south-eastern Kazakhstan are characterized. The new species differ from other species of the genus by the morphology of the scolex, the relative position and length of the cirrus-sac and the relative position and arrangement of the testes. Differential criteria of species of Hymenolepis (sensu stricto) are also discussed.

  9. First Miocene rodent from Lebanon provides the 'missing link' between Asian and African gundis (Rodentia: Ctenodactylidae).

    PubMed

    López-Antoñanzas, Raquel; Knoll, Fabien; Maksoud, Sibelle; Azar, Dany

    2015-08-07

    Ctenodactylinae (gundis) is a clade of rodents that experienced, in Miocene time, their greatest diversification and widest distribution. They expanded from the Far East, their area of origin, to Africa, which they entered from what would become the Arabian Peninsula. Questions concerning the origin of African Ctenodactylinae persist essentially because of a poor fossil record from the Miocene of Afro-Arabia. However, recent excavations in the Late Miocene of Lebanon have yielded a key taxon for our understanding of these issues. Proafricanomys libanensis nov. gen. nov. sp. shares a variety of dental characters with both the most primitive and derived members of the subfamily. A cladistic analysis demonstrates that this species is the sister taxon to a clade encompassing all but one of the African ctenodactylines, plus a southern European species of obvious African extraction. As such, Proafricanomys provides the 'missing link' between the Asian and African gundis.

  10. Seasonal changes in body composition of Ctenomys talarum (Rodentia: Octodontidae): an herbivore subterranean rodent.

    PubMed

    del Valle, Juana C; López Mañanes, Alejandra A; Busch, Cristina

    2006-09-01

    Ctenomys talarum is a subterranean herbivorous rodent whose burrow systems exhibit particular characteristics, distinct from other subterranean environments. We studied seasonal variation in body composition of C. talarum in relation to energetic requirements. Body lipid content seasonally changed in C. talarum, related to reproductive cycle and thermorregulatory mechanisms. A decrease in protein body content was found only in spring. Ash content of females was lowest when most of them are in post partum estro. Observed variations in water body content could be associated with plant water content and/or metabolic regulation. Our results show the occurrence of seasonal variations in body composition in C. talarum, which could be related to the high cost of reproduction and the subterranean life style of this species.

  11. Fatal placental subinvolution in a captive capybara (Hydrochaeris hydrochaeris, Order Rodentia).

    PubMed

    Juan-Sallés, C; Martínez, L S; Garner, M M

    2005-07-01

    An adult, captive-born female capybara died of systemic thrombosis and hemoperitoneum associated with placental subinvolution. Grossly, the uterus was enlarged, segmentally thickened, and associated with a large blood clot in the abdominal cavity. There was hemometra and a large ovoid mass in each uterine horn weakly adhered to the endometrium, and the right uterine horn wall had a small perforation over the mass. The mesometrial veins were markedly dilated due to thrombosis and occasionally perforated. Histologically, the uterine masses consisted of partly necrotic placental and subplacental tissue. The uterine wall surrounding the masses had full-thickness coagulative necrosis of the myometrium and diffuse endometrial ulceration with abundant syncytiotrophoblast-like cells within capillaries. Vascular lesions in the uterus and mesometrium consisted of mural invasion by cytotrophoblast and syncytiotrophoblast-like cells, thrombosis, fibrinoid necrosis, and/or heterophilic vasculitis. This is the first report of placental subinvolution in capybaras or any rodent species, to the authors' knowledge.

  12. Complete mitochondrial genome of the Gansu zokor, Eospalax cansus (Rodentia, Spalacidae).

    PubMed

    Su, Junhu; Wang, Jing; Hua, Limin; Gleeson, Dianne; Ji, Weihong

    2013-12-01

    Mysopalacinae (zokors) is a group of fossorial rodents for which the taxonomy has yet to reach consensus. Furthermore, due to their fossorial lifestyle, little is known about their ecology. Molecular data are important to elucidate such aspects. In this paper, the complete mitochondrial DNA genome of Gansu zokor (Eospalax cansus) of the type found in Lintan, China was determined. The genome is 16,354 bp in length and consists of 13 protein-coding genes, 22 tRNA genes, two ribosomal RNA genes, and two main non-coding regions (the control region and the origin of the light strand replication), the gene composition and order of which are similar to most other mammals. The overall base composition is T 30.0%, C 24.2%, A 33.5%, and G 12.3%, with an A + T bias of 63.5%. These mitogenome sequence data are potentially important for evolutionary, population genetic, and ecological studies of the Mysopalacinae.

  13. Parasitism underground: lice (Insecta: Phthiraptera) from Ctenomys talarum (Rodentia: Ctenomyidae) along its coastal distribution in Argentina.

    PubMed

    Martino, Natalia S; Romero, Mariano D; Malizia, Ana I

    2014-03-01

    Species of South American subterranean rodents belonging to the genus Ctenomys (commonly called tuco-tucos) are widely distributed across the southern Neotropical region. Despite their relatively well-studied biology and reproductive physiology, current knowledge of their ectoparasite fauna is limited to a few ambiguous studies, based on scattered samples from a small number of host individuals. Ctenomys talarum is the most widely distributed species in the genus. Lice (Phthiraptera) were collected from these tuco-tucos throughout their entire coastal range. Two species, one chewing louse (Gyropus parvus), and one sucking louse (Eulinognathus americanus) were collected. The distribution ranges for both louse species were extended with new locality records. No lice were found in two host populations. Furthermore, co-occurrence of both ectoparasites was not detected.

  14. Early evolutionary differentiation of morphological variation in the mandible of South American caviomorph rodents (Rodentia, Caviomorpha).

    PubMed

    Alvarez, A; Perez, S I; Verzi, D H

    2011-12-01

    Caviomorphs are a clade of South American rodents recorded at least since the early Oligocene (> 31.5 Ma) that exhibit ample eco-morphological variation. It has been proposed that phylogenetic structure is more important than ecological factors for understanding mandibular shape variation in this clade. This was interpreted as a result of the long-standing evolutionary history of caviomorphs and the early divergence of major lineages. In this work, we test this hypothesis through the analysis of morphological variation in the mandible of living and extinct species and compare this information with that obtained through comparative phylogenetic analyses. Our results support the hypothesis of early origin of mandibular variation; moreover, they suggest the conservation of early differentiated morphologies, which could indicate the existence of constrained evolutionary diversification.

  15. Predicting the potential distribution of Vexillata (Nematoda: Ornithostrongylidae) and its hosts (Mammalia: Rodentia) within America.

    PubMed

    Martínez-Salazar, E A; Escalante, T; Linaje, M; Falcón-Ordaz, J

    2013-12-01

    Species distribution modelling has been a powerful tool to explore the potential distribution of parasites in wildlife, being the basis of studies on biogeography. Vexillata spp. are intestinal nematodes found in several species of mammalian hosts, such as rodents (Geomyoidea) and hares (Leporidae) in the Nearctic and northern Neotropical regions. In the present study, we modelled the potential distribution of Vexillata spp. and their hosts, using exclusively species from the Geomyidae and Heteromyidae families, in order to identify their distributional patterns. Bioclimatic and topographic variables were used to identify and predict suitable habitats for Vexillata and its hosts. Using these models, we identified that temperature seasonality is a significant environmental factor that influences the distribution of the parasite genus and its host. In particular, the geographical distribution is estimated to be larger than that predicted for its hosts. This suggests that the nematode has the potential to extend its geographical range and also its spectrum of host species. Increasing sample size and geographical coverage will contribute to recommendations for conservation of this host-parasite system.

  16. Diversification and biogeography of the Neotropical caviomorph lineage Octodontoidea (Rodentia: Hystricognathi).

    PubMed

    Upham, Nathan S; Patterson, Bruce D

    2012-05-01

    The rodent superfamily Octodontoidea comprises 6 families, 38 genera, and 193 living species of spiny rats, tuco-tucos, degus, hutias, and their relatives. All are endemic to the Neotropical Region where they represent roughly three-quarters of extant caviomorphs. Although caviomorph monophyly is well established and phylogenetic hypotheses exist for several families, understanding of octodontoid relationships is clouded by sparse taxon sampling and single-gene analyses. We examined sequence variation in one mitochondrial (12S rRNA) and three nuclear genes (vWF, GHR, and RAG1) across all caviomorph families (including 47 octodontoid species), all phiomorph families, and the sole remaining hystricognath family, using the gundi (Ctenodactylus) and springhaas (Pedetes) as outgroups. Our analyses support the monophyly of Phiomorpha, Caviomorpha, and the caviomorph superfamilies Cavioidea (Dasyproctidae, Cuniculidae, and Caviidae, the latter including Hydrochoerus), Erethizontoidea, Chinchilloidea (including Dinomyidae), and Octodontoidea. Cavioids and erethizontoids are strongly supported as sisters, whereas chinchilloids appear to be sister to octodontoids. Among octodontoids, Abrocomidae is consistently recovered as the basal element, sister to a pair of strongly supported clades; one includes Octodontidae and Ctenomyidae as reciprocally monophyletic lineages, whereas the other includes taxa currently allocated to Echimyidae, Capromyidae and Myocastoridae. Capromys appears near the base of this clade, in keeping with current classification, but Myocastor is nested securely inside a clade of Echimyidae that also contains eumysopines, echimyines and dactylomyines. Another, more weakly supported clade of Echimyidae contains fossorial and scansorial taxa from the Chaco-Cerrado-Caatinga and the Atlantic Forest. Biogeographic analyses robustly recover the Patagonia-Southern Andes complex as ancestral for the Octodontoidea, with three component lineages emerging by the Oligocene-Miocene boundary (∼23Ma): (1) stem abrocomids in the Central and Southern Andes; (2) a lineage leading to octodontids plus ctenomyids in Patagonia, later dispersing into the Chaco-Cerrado-Caatinga; and (3) a lineage leading to echimyids, capromyids, and myocastorids that subsequently radiated in more mesic biomes, including Amazonia, Atlantic Forest, and the Antilles. This reconstruction refutes earlier ideas that the diverse, generalized, mainly lowland family Echimyidae, which appears early in the fossil record, gave rise to the Andean lineages of octodontoids-instead, the reverse derivation appears to be true. We recommend formal synonymy of Myocastoridae with Echimyidae but defer a similar treatment of Capromyidae until additional hutia taxa and sequences can be analyzed.

  17. Phylogenetic relationships of extant zokors (Myospalacinae) (Rodentia, Spalacidae) inferred from mitochondrial DNA sequences.

    PubMed

    Su, Junhu; Ji, Weihong; Wang, Jing; Gleeson, Dianne M; Zhou, Janwei; Hua, Limin; Wei, Yanming

    2014-04-01

    In this study, we use three mitochondrial markers, cytochrome b gene (Cyt b), NADH dehydrogenase subunit 4 (ND4) and control region (D-loop) to investigate the phylogenetic relationships of extant zokor species in Mysopalacinae. The phylogenetic tree constructed based on Cyt b strongly supports the monophyly genera Eospalax and Myospalax with E. fontanierii being the most ancient species in Eospalax. Further phylogenetic analyses of four species of Eospalax based on ND4 and D-loop sequences revealed two clades that correspond to two geographical distributions. The basal clade includes E. cansus which is mainly found on Loess Plateau (LP) and another clade including E. baileyi, E. smithii and E. rufescens that inhabits areas above 2000 m on Qinghai-Tibetan Plateau (QTP) and Qinling Mountains. Geographical events of QTP and LP may have played a major role in the diversification and evolution of Mysopalacinae.

  18. Another one bites the dust: bite force and ecology in three caviomorph rodents (Rodentia, Hystricognathi).

    PubMed

    Becerra, Federico; Echeverría, Alejandra Isabel; Casinos, Adrià; Vassallo, Aldo Iván

    2014-04-01

    Mammals have developed sophisticated strategies adapting to particular locomotor modes, feeding habits, and social interactions. Many rodent species have acquired a fossorial, semi-fossorial, or even subterranean life-style, converging on morphological, anatomical, and ecological features but diverging in the final arrangement. These ecological variations partially depend on the functional morphology of their digging tools. Muscular and mechanical features (e.g., lever arms relationship) of the bite force were analyzed in three caviomorph rodents with similar body size but different habits and ecological demands of the jaws. In vivo forces were measured at incisors' tip using a strain gauge load cell force transducer whereas theoretical maximal performance values, mechanical advantages, and particular contribution of each adductor muscle were estimated from dissections in specimens of Ctenomys australis (subterranean, solitary), Octodon degus (semi-fossorial, social), and Chinchilla laniger (ground-dweller, colonial). Our results showed that C. australis bites stronger than expected given its small size and C. laniger exhibited the opposite outcome, while O. degus is close to the expected value based on mammalian bite force versus body mass regressions; what might be associated to the chisel-tooth digging behavior and social interactions. Our key finding was that no matter how diverse these rodents' skulls were, no difference was found in the mechanical advantage of the main adductor muscles. Therefore, interspecific differences in the bite force might be primarily due to differences in the muscular development and force, as shown for the subterranean, solitary and territorial C. australis versus the more gracile, ground-dweller, and colonial C. laniger.

  19. The evolution of fossoriality and the adaptive role of horns in the Mylagaulidae (Mammalia: Rodentia)

    PubMed Central

    Hopkins, Samantha S.B

    2005-01-01

    Ceratogaulus, a member of the extinct fossorial rodent clade Mylagaulidae, is the only known rodent with horns and the smallest known horned mammal. The function of the large, dorsally projecting nasal horns on this burrowing animal has been the subject of wide speculation among palaeontologists; suggested uses range from sexual combat to burrowing. Mammals have evolved adaptations for digging repeatedly; horns and other cranial appendages have also evolved numerous times. These two adaptations co-occur in mammals extremely rarely: only two fossil genera (Ceratogaulus and the xenarthran Peltephilus) and no extant mammals are both horned and fossorial. Tracing the evolution of fossoriality in aplodontoid rodents (the larger clade to which Ceratogaulus belongs) reveals that Ceratogaulus descended from ancestors who dug by head-lifting. Whereas this suggests an obvious explanation for the horns of this rodent, evidence from functional morphology, anatomy, phylogeny and geologic context indicates that the horns in Ceratogaulus were used for defence, rather than digging, and evolved to offset increased predation costs associated with spending more time foraging above ground as body size increased. PMID:16087426

  20. Re-Evaluation of Sinocastor (Rodentia: Castoridae) with Implications on the Origin of Modern Beavers

    PubMed Central

    Rybczynski, Natalia; Ross, Elizabeth M.; Samuels, Joshua X.; Korth, William W.

    2010-01-01

    The extant beaver, Castor, has played an important role shaping landscapes and ecosystems in Eurasia and North America, yet the origins and early evolution of this lineage remain poorly understood. Here we use a geometric morphometric approach to help re-evaluate the phylogenetic affinities of a fossil skull from the Late Miocene of China. This specimen was originally considered Sinocastor, and later transferred to Castor. The aim of this study was to determine whether this form is an early member of Castor, or if it represents a lineage outside of Castor. The specimen was compared to 38 specimens of modern Castor (both C. canadensis and C. fiber) as well as fossil specimens of C. fiber (Pleistocene), C. californicus (Pliocene) and the early castorids Steneofiber eseri (early Miocene). The results show that the specimen falls outside the Castor morphospace and that compared to Castor, Sinocastor possesses a: 1) narrower post-orbital constriction, 2) anteroposteriorly shortened basioccipital depression, 3) shortened incisive foramen, 4) more posteriorly located palatine foramen, 5) longer rostrum, and 6) longer braincase. Also the specimen shows a much shallower basiocciptal depression than what is seen in living Castor, as well as prominently rooted molars. We conclude that Sinocastor is a valid genus. Given the prevalence of apparently primitive traits, Sinocastor might be a near relative of the lineage that gave rise to Castor, implying a possible Asiatic origin for Castor. PMID:21085579

  1. Dental microwear patterns of extant and extinct Muridae (Rodentia, Mammalia): ecological implications

    NASA Astrophysics Data System (ADS)

    Gomes Rodrigues, Helder; Merceron, Gildas; Viriot, Laurent

    2009-04-01

    Extant species of Muridae occupy a wide array of habitats and have diverse dietary habits. Consequently, their dental microwear patterns represent a potential clue to better understand the paleoecology of their extinct relatives, which are abundant in many Old World Neogene localities. In this study, dental microwear is investigated for specimens of 17 extant species of murine and deomyine rodents in order to test the reliability of this method and infer dietary preferences on the fossil species Saïdomys afarensis. This extinct form comes from a mid-Pliocene site (AL 327) located at the Hadar Formation (Ethiopia) known to have delivered many hominid specimens of Australopithecus afarensis. A significant correlation between microwear patterns and diet is detected. Thus, grass, fruit, and insect eaters display, respectively, high amounts of fine scratches, wide scratches, and large pits. Moreover, some aspects of the paleoecology of S. afarensis, including feeding habits, could be assessed in regard to its dental microwear pattern. Indeed, it probably had feeding habits similar to that of living grass eaters. These results concur with the presence of open to woodland areas covered by an herbaceous vegetal layer, including monocotyledons, in the vicinity of this mid-Pliocene locality.

  2. Dental microwear patterns of extant and extinct Muridae (Rodentia, Mammalia): ecological implications.

    PubMed

    Rodrigues, Helder Gomes; Merceron, Gildas; Viriot, Laurent

    2009-04-01

    Extant species of Muridae occupy a wide array of habitats and have diverse dietary habits. Consequently, their dental microwear patterns represent a potential clue to better understand the paleoecology of their extinct relatives, which are abundant in many Old World Neogene localities. In this study, dental microwear is investigated for specimens of 17 extant species of murine and deomyine rodents in order to test the reliability of this method and infer dietary preferences on the fossil species Saïdomys afarensis. This extinct form comes from a mid-Pliocene site (AL 327) located at the Hadar Formation (Ethiopia) known to have delivered many hominid specimens of Australopithecus afarensis. A significant correlation between microwear patterns and diet is detected. Thus, grass, fruit, and insect eaters display, respectively, high amounts of fine scratches, wide scratches, and large pits. Moreover, some aspects of the paleoecology of S. afarensis, including feeding habits, could be assessed in regard to its dental microwear pattern. Indeed, it probably had feeding habits similar to that of living grass eaters. These results concur with the presence of open to woodland areas covered by an herbaceous vegetal layer, including monocotyledons, in the vicinity of this mid-Pliocene locality.

  3. Distinct Leishmania Species Infecting Wild Caviomorph Rodents (Rodentia: Hystricognathi) from Brazil

    PubMed Central

    Cássia-Pires, Renata; Boité, Mariana C.; D'Andrea, Paulo S.; Herrera, Heitor M.; Cupolillo, Elisa; Jansen, Ana Maria; Roque, André Luiz R.

    2014-01-01

    Background Caviomorph rodents, some of the oldest Leishmania spp. hosts, are widely dispersed in Brazil. Despite both experimental and field studies having suggested that these rodents are potential reservoirs of Leishmania parasites, not more than 88 specimens were analyzed in the few studies of natural infection. Our hypothesis was that caviomorph rodents are inserted in the transmission cycles of Leishmania in different regions, more so than is currently recognized. Methodology We investigated the Leishmania infection in spleen fragments of 373 caviomorph rodents from 20 different species collected in five Brazilian biomes in a period of 13 years. PCR reactions targeting kDNA of Leishmania sp. were used to diagnose infection, while Leishmania species identification was performed by DNA sequencing of the amplified products obtained in the HSP70 (234) targeting. Serology by IFAT was performed on the available serum of these rodents. Principal findings In 13 caviomorph rodents, DNA sequencing analyses allowed the identification of 4 species of the subgenus L. (Viannia): L. shawi, L. guyanensis, L. naiffi, and L. braziliensis; and 1 species of the subgenus L. (Leishmania): L. infantum. These include the description of parasite species in areas not previously included in their known distribution: L. shawi in Thrichomys inermis from Northeastern Brazil and L. naiffi in T. fosteri from Western Brazil. From the four other positive rodents, two were positive for HSP70 (234) targeting but did not generate sequences that enabled the species identification, and another two were positive only in kDNA targeting. Conclusions/Significance The infection rate demonstrated by the serology (51.3%) points out that the natural Leishmania infection in caviomorph rodents is much higher than that observed in the molecular diagnosis (4.6%), highlighting that, in terms of the host species responsible for maintaining Leishmania species in the wild, our current knowledge represents only the “tip of the iceberg.” PMID:25503973

  4. Digital dissection of the masticatory muscles of the naked mole-rat, Heterocephalus glaber (Mammalia, Rodentia)

    PubMed Central

    Faulkes, Chris G.

    2014-01-01

    The naked mole-rat, Heterocephalus glaber, of the family Bathyergidae is a subterranean rodent that feeds on underground roots and tubers and digs extensive tunnel systems with its incisors. It is a highly unusual mammal with regard to its social structure, longevity, pain insensitivity and cancer resistance, all of which have made it the subject of a great deal of research in recent years. Yet, much of the basic anatomy of this species remains undocumented. In this paper, we describe the morphology of the jaw-closing musculature of the naked mole-rat, as revealed by contrast-enhanced micro-computed tomography. This technique uses an iodine stain to enable the imaging of soft tissues with microCT. The iodine-enhanced scans were used to create 3D reconstructions of the naked mole-rat masticatory muscles from which muscle masses were calculated. The jaw-closing musculature of Heterocephalus glaber is relatively very large compared to other rodents and is dominated by the superficial masseter, the deep masseter and the temporalis. The temporalis in particular is large for a rodent, covering the entirety of the braincase and much of the rear part of the orbit. The morphology of the masseter complex described here differs from two other published descriptions of bathyergid masticatory muscles, but is more similar to the arrangement seen in other rodent families. The zygomaticomandibularis (ZM) muscle does not protrude through the infraorbital foramen on to the rostrum and thus the naked mole-rat should be considered protrogomorphous rather than hystricomorphous, and the morphology is consistent with secondarily lost hystricomorphy as has been previously suggested for Bathyergidae. Overall, the morphology of the masticatory musculature indicates a species with a high bite force and a wide gape–both important adaptations for a life dominated by digging with the incisors. PMID:25024917

  5. Genetic variations of Turkish bank vole, Myodes glareolus (Mammalia: Rodentia) inferred from mtDNA.

    PubMed

    Çolak, Reyhan; Olgun Karacan, Gül; Kandemir, Irfan; Çolak, Ercüment; Kankiliç, Teoman; Yigit, Nuri; Michaux, Johan

    2016-11-01

    The bank vole, Myodes glareolus, lives in deciduous forests throughout the Palearctic region. In Turkey, this species is distributed only in northern Anatolia (the Black Sea region) where these forests exist. This study reveals genetic differentiation among bank vole populations based on two regions of mitochondrial DNA (cytochrome b and D-loop). Populations in northern Anatolia are divided into two genetic lineages (the "eastern" and "western Black Sea" lineages) by the Kızılırmak Valley. While the western Black Sea lineage is close to the Balkan lineage, in accordance with their geographical proximities, surprisingly, the Uludag lineage, also situated in Western Turkey appears related to the eastern Black Sea population. The divergence time analyses suggest a separation between the Balkan and Turkish groups around 0.26 Mya, whereas the split between the eastern and western Black sea lineages appeared a little bit later (0.20 Mya). Our results suggest that regional refuges existed for this species in Turkey and that small-scale habitat fragmentations led to genetic differentiations between Myodes populations.

  6. Species groups in Proechimys (Rodentia: Echimyidae) as indicated by karyology and bullar morphology

    USGS Publications Warehouse

    Gardner, A.L.; Emmons, L.H.

    1984-01-01

    The genus Proechimys is divisible into four groups of species on the basis of bullar septal patterns. Each of the four groups can be further characterized by distinctive distributions and karyotypes. The subgenus Trinomys and the guatrae species group each are comprised of phylogenetically closely-related species. The semispinosus- and brevicauda-groups, although generally distinctive on the basis of bullar septa, are not phylogenetically equivalent to the first two groups. The brevicauda-group, for example, consists of at least three separate species complexes. The taxonomy used in this report reflects several nomenclatural changes from that used in the recent literature. In addition, previously unreported karyotypes are described for P. quadruplicatus, P. gularis, P. decumanus, P. oris, P. oconnelli, and P. mincae.

  7. Bots (Diptera: Oestridae) infesting a neotropical forest rodent, Proechimys semispinosus (Rodentia: Echimyidae), in Panama.

    PubMed

    Adler, Gregory H; Davis, Shannon L; Carvajal, Alejandra

    2003-08-01

    Botfly larvae (Cuterebra sp.) infesting spiny rats (Proechimys semispinosus) in 8 small islands in the Panama Canal were studied. Rats were live trapped monthly on each island from January 1991 through February 2000 and visually examined for the presence of bots. Overall, bot prevalence was 4.6% and differed statistically among island rat populations. Rats were simultaneously infested by as many as 4 bots. Overall bot intensity was 1.3 bots per infested rat and did not differ among islands. Mean bot density across all islands was 0.0111 and was greater during the dry seasons than during the rainy seasons, but it did not differ among islands. Bots were found during all the 12 calendar months, suggesting a multivoltine reproductive schedule. Although bot activity varied seasonally, there was little synchrony of bot activity among islands. Bot density was related negatively to rainfall but was not related to host density, suggesting that drier ambient conditions may promote reproduction by adult bot flies in this system.

  8. Homomorphic sex chromosomes and the intriguing Y chromosome of Ctenomys rodent species (Rodentia, Ctenomyidae).

    PubMed

    Suárez-Villota, Elkin Y; Pansonato-Alves, José C; Foresti, Fausto; Gallardo, Milton H

    2014-01-01

    Unlike the X chromosome, the mammalian Y chromosome undergoes evolutionary decay resulting in small size. This sex chromosomal heteromorphism, observed in most species of the fossorial rodent Ctenomys, contrasts with the medium-sized, homomorphic acrocentric sex chromosomes of closely related C. maulinus and C. sp. To characterize the sequence composition of these chromosomes, fluorescent banding, self-genomic in situ hybridization, and fluorescent in situ hybridization with an X painting probe were performed on mitotic and meiotic plates. High molecular homology between the sex chromosomes was detected on mitotic material as well as on meiotic plates immunodetected with anti-SYCP3 and anti-γH2AX. The Y chromosome is euchromatic, poor in repetitive sequences and differs from the X by the loss of a block of pericentromeric chromatin. Inferred from the G-banding pattern, an inversion and the concomitant prevention of recombination in a large asynaptic region seems to be crucial for meiotic X chromosome inactivation. These peculiar findings together with the homomorphism of Ctenomys sex chromosomes are discussed in the light of the regular purge that counteracts Muller's ratchet and the probable mechanisms accounting for their origin and molecular homology.

  9. Gamasine mite (Parasitiformes: Mesostigmata) infestations of small mammals (Mammalia: Rodentia, Insectivora) in Turkey.

    PubMed

    Cicek, Hatice; Stanyukovich, Maria; Yağci, Sukran; Aktaş, Metin; Karaer, Zafer

    2008-01-01

    The present study was conducted on small mammals from different locations in Turkey. One hundred twenty- three individuals representing 11 species of rodents and insectivora were investigated for mite ectoparasites. A total of 126 gamasine mites were collected from 96 individuals (78.1%) of 6 species of small mammals. Five gamasine families were recorded: Laelapidae, Hirstionyssidae, Haemogamasidae, Macronyssidae and Macrochelidae. Laelaps jettmari Vitzthum (72 species) was predominant and found mainly on Mus musculus (Linnaeus) and Cricetulus migratorius (Pallas). New species of gamasine mites and host records for Turkey are given.

  10. Mandible shape and dwarfism in squirrels (Mammalia, Rodentia): interaction of allometry and adaptation

    NASA Astrophysics Data System (ADS)

    Hautier, Lionel; Fabre, Pierre-Henri; Michaux, Jacques

    2009-06-01

    Squirrels include several independent lineages of dwarf forms distributed into two ecological groups: the dwarf tree and flying squirrels. The mandible of dwarf tree squirrels share a highly reduced coronoid process and a condylar process drawn backwards. Dwarf flying squirrels on the other hand, have an elongated coronoid process and a well-differentiated condylar process. To interpret such a difference, Elliptic Fourier Transform was used to evaluate how mandible shape varies with dwarfism in sciurids. The results obtained show that this clear-cut difference cannot be explained by a simple allometric relationship in relation with size decrease. We concluded that the retention of anteriorly positioned eye sockets, in relation with distance estimation, allowed the conservation of a well-differentiated coronoid process in all flying species, despite the trend towards its reduction observed among sciurids as their size decreases.

  11. Ectoparasites of the critically endangered insular cavy, Cavia intermedia (Rodentia: Caviidae), southern Brazil.

    PubMed

    Regolin, André Luis; Furnari, Nina; de Castro Jacinavicius, Fernando; Linardi, Pedro Marcos; de Carvalho-Pinto, Carlos José

    2015-04-01

    Cavia intermedia is a rodent species critically endangered and is found only on a 10 hectare island off the southern Brazilian coast. To identify the ectoparasites of C. intermedia, 27 specimens (14 males and 13 females), representing approximately 65% of the estimated total population, were captured and examined. A total of 1336 chewing lice of two species were collected: Gliricola lindolphoi (Amblycera: Gyropidae) and Trimenopon hispidum (Amblycera: Trimenoponidae). In addition, chiggers Arisocerus hertigi (Acari: Trombiculidae) and Eutrombicula sp. (Acari: Trombiculidae) were collected from the ears of all captured animals. This low species richness compared to those for other Cavia species is expected for island mammals. Although the results presented here are not conclusive about the relationship between C. intermedia and ectoparasites, this low species richness found might be reflected in a low level of investment by the hosts in the basal immune defense, since investments in white blood cell production by mammals are influenced by the diversity of parasites in the environment. Additionally, considering that it might result in host vulnerability to other parasites that might be introduced through exotic or migratory host species, the monitoring of C. intermedia, including parasitological and immunological assessments, is recommended as a key component of conservation efforts.

  12. Scaling and adaptations of incisors and cheek teeth in caviomorph rodents (Rodentia, Hystricognathi).

    PubMed

    Becerra, Federico; Vassallo, Aldo I; Echeverría, Alejandra I; Casinos, Adrià

    2012-10-01

    The South American hystricognath rodents are one of the most diverse mammalian clades considering their occupied habitats, locomotor modes and body sizes. This might have been partly evolved by diversification of their masticatory apparatus' structure and its ecological commitment, for example, chisel-tooth digging. In this phylogeny-based comparative study, we test the relationship between ecological behavior and mechanical features of their incisors and molariforms. In 33 species of nine families of caviomorph rodents, we analyze incisor attributes related to structural stress resistance and molar features related with grinding capacity, for example, second moment of inertia and enamel index (EI) (enamel band length/occlusal surface area), respectively. Most of these variables scaled isometrically to body mass, with a strong phylogenetic effect. A principal component analysis discrimination on the EI clustered the species according to their geographic distribution. We presume that selective pressures in Andean-Patagonian regions, on particular feeding habits and chisel-tooth digging behaviors, have modeled the morphological characteristics of the teeth. Subterranean/burrower ctenomyids, coruros, and plains viscachas showed the highest bending/torsion strength and anchorage values for incisors; a simplified enamel pattern in molariforms would be associated with a better grinding of the more abrasive vegetation present in more open and drier biomes.

  13. On the Indian crested porcupine, Hystrix indica (Kerr, 1792) in Turkey (Mammalia: Rodentia).

    PubMed

    Arslan, Atilla

    2008-01-15

    This study presents some data about ecological, biological and taxonomical characteristics of Hystrix indica (Kerr, 1792) from Turkey. For this purpose characteristics of burrow, skull, tooth and measurements of external and cranial characters of two female H. indica from Turkey were investigated. It was concluded that our specimens are between the Middle East and Indian sub-region specimens in terms of morphometrical. It was also determined that there were roots in stomach contents of specimens.

  14. Records of Coendou ichillus (Rodentia, Erethizontidae) from the Lower Urubamba Region of Peru

    PubMed Central

    Gregory, Tremaine; Lunde, Darrin; Zamora-Meza, Hugo Tomás; Carrasco-Rueda, Farah

    2015-01-01

    Abstract Coendou ichillus was first described in 2001 by Voss and da Silva, with a range from Amazonian Ecuador to Iquitos, Peru. Here, we describe an adult female Coendou ichillus specimen collected in a Tomahawk trap in the forest canopy of the Lower Urubamba Region of Peru in October 2013. We also describe pathologies and behaviors observed through 379 camera trapping photo events (2,196 photos) gathered in natural canopy bridges over the course of a year (7,198 trap nights), including information on activity period over the course of the day and over the course of the lunar cycle. We conservatively estimate that 17 individuals were photographed, including one juvenile. Being 900 km away from Iquitos, Peru (the site of the closest record), discovery of this species in the Lower Urubamba constitutes a significant range extension. PMID:26175605

  15. Field evaluation of some bait additives against Indian crested porcupine (Hystrix indica) (Rodentia: Hystricidae).

    PubMed

    Mushtaq, Muhammad; Hussain, Iftikhar; Mian, Afsar; Munir, Shahid; Ahmed, Irfan; Khan, Abdul Aziz

    2013-09-01

    This research study evaluated the effect of different additives on the bait consumption by Indian crested porcupine, a serious forest and agricultural pest, under field conditions. Different additives (saccharin, common salt, bone meal, fish meal, peanut butter, egg yolk, egg shell powder, yeast powder, mineral oil and coconut oil) at 2 and 5% each were tested for their relative preference, using groundnut-maize (1:1) as basic bait. All the additives were tested under a no-choice test pattern. For control tests, no additive was mixed with the basic bait. Saccharin at 5% concentration significantly enhanced the consumption of bait over the basic bait, while 2% saccharin supplemented bait resulted in a non-significant bait consumption. All other additives did not enhance the consumption of the bait material; rather, these worked as repellents. However, the repellency was lowest with the common salt, followed by egg yolk, egg shell powder, bone meal, peanut butter, mineral oil, fish meal and yeast powder, while coconut remained the most repellent compound. The present study suggested that groundnut-maize (1:1) supplemented with 5% saccharin was the preferred bait combination, and can be used with different rodenticides for the management of Indian crested porcupine.

  16. Functional anatomy of the limbs of erethizontidae (Rodentia, Caviomorpha): Indicators of locomotor behavior in Miocene porcupines.

    PubMed

    Candela, Adriana M; Picasso, Mariana B J

    2008-05-01

    Functional analysis of the limb bones of the erethizontid Steiromys duplicatus, one of the most abundant Miocene porcupines from Patagonia, provides evidence to infer their locomotor behavior. Remains of the giant Neosteiromys pattoni (Late Miocene of Northeast Argentina) are also analyzed. Osteological and myological features of extant porcupines were evaluated and used as a model to interpret the functional significance of Miocene species' limbs. Several features in erethizontids are compatible with the ability to climb: the low humeral tuberosities indicate a mobile gleno-humeral joint; the prominent and distally extended deltopectoral crest indicates a powerful pectoral muscle, which is particularly active when climbing; the humero-ulnar and humero-radial joints are indicative of pronation-supination movements; the well-developed lateral epicondylar ridge and the medially protruding entepicondyle are in agreement with an important development of the brachioradialis, supinator, flexor digitorum profundus, and pronator teres muscles, acting in climbing and grasping functions; the mechanical advantage of the biceps brachii would be emphasized because of its distal attachment on the bicipital tuberosity. As with extant porcupines, in Miocene species, the large femoral head would have permitted a broad range of abduction of the femur, and the medially protruding lesser trochanter would have emphasized the abduction and outward rotation of the femur by the action of the ilio-psoas complex. In S. duplicatus, the shape of the hip, knee, and cruro-astragalar, calcaneo-astragalar, and astragalo-navicular joints would have allowed lateral and rotational movements, although probably to a lesser degree than in extant porcupines. Foot features of S. duplicatus (e.g., great medial sesamoid bone, medial astragalar head, complete hallux) indicate that this species would have had grasping ability, but would not have achieved the high degree of specialization of Coendou. Steiromys duplicatus would have been a semiarboreal dweller, resembling Erethizon dorsatum.

  17. Records of Coendouichillus (Rodentia, Erethizontidae) from the Lower Urubamba Region of Peru.

    PubMed

    Gregory, Tremaine; Lunde, Darrin; Zamora-Meza, Hugo Tomás; Carrasco-Rueda, Farah

    2015-01-01

    Coendouichillus was first described in 2001 by Voss and da Silva, with a range from Amazonian Ecuador to Iquitos, Peru. Here, we describe an adult female Coendouichillus specimen collected in a Tomahawk trap in the forest canopy of the Lower Urubamba Region of Peru in October 2013. We also describe pathologies and behaviors observed through 379 camera trapping photo events (2,196 photos) gathered in natural canopy bridges over the course of a year (7,198 trap nights), including information on activity period over the course of the day and over the course of the lunar cycle. We conservatively estimate that 17 individuals were photographed, including one juvenile. Being 900 km away from Iquitos, Peru (the site of the closest record), discovery of this species in the Lower Urubamba constitutes a significant range extension.

  18. A new species of Sciurodendrium (Nematoda: Heligmonellidae) in Sciurus aureogaster (Rodentia: Sciuridae) from Morelos, Mexico.

    PubMed

    Falcón-Ordaz, Jorge; Lamothe-Argumedo, Marcos Rafael

    2006-06-01

    Sciurodendrium bravohollisae n. sp. (Heligmonellidae) is described as an intestinal parasite of 2 squirrels, Sciurus aureogaster Cuvier, 1829, collected from Los Robles, Municipio de Tlalnepantla, Morelos State, Mexico. The new species differs from all other congeners in possessing a very well-developed and sacciform genital cone. This is the seventh species described for the genus and the first one recorded in Mexico.

  19. Late cenozoic history of the genus Micromys (mammalia, rodentia) in Central Europe.

    PubMed

    Horáček, Ivan; Knitlová, Markéta; Wagner, Jan; Kordos, László; Nadachowski, Adam

    2013-01-01

    Molecular phylogeography suggests that Micromys minutus, the sole extant species of the genus, colonized its extensive range quite recently, during the Late Pleistocene-Holocene period. Rich Pliocene and Pleistocene fossil records both from Europe and China suggest rather continuous and gradual in situ phenotype rearrangements from the Pliocene to the Recent periods. To elucidate the discrepancy we reexamined a considerable part of the European fossil record of the genus (14 sites from MN15 to Q3, 0.4-4.2 Ma, including the type series of M. preaminutus from MN15 Csarnóta 2), analyzed them with the aid of detailed morphometric comparisons, and concluded that: (a) The European Pliocene form, M. praeminutus, differs significantly from the extant species; (b) it exhibits a broad phenotypic variation covering the presumptive diagnostic characters of MN16 M. caesaris; (c) despite having smaller dimensions, the Early and Middle Pleistocene forms (MN17-Q3, 2.6-0.4 Ma) seem to be closer to M. praeminutus than to the extant species; (d) the extinction of M. praeminutus during Q3 and the re-occupation of its niche by the recent expansion of M. minutus from E-European-C Asiatic sources (suggested by phylogeographic hypotheses) cannot be excluded. Discussing interpretations of the phylogenetic past of the genus we emphasize the distinct history of the West Palearctic clade (Late Miocene-Early Pleistocene) terminating with M. praeminutus and the East Asiatic clade (chalceus, tedfordi, minutus), and the possible identity of the Western clade with the Late Miocene genus Parapodemus.

  20. Taxonomic hypotheses regarding the genus Gerbillus (Rodentia, Muridae, Gerbillinae) based on molecular analyses of museum specimens

    PubMed Central

    Ndiaye, Arame; Tatard, Caroline; Stanley, William; Granjon, Laurent

    2016-01-01

    Abstract Methodological improvements now allow routine analyses of highly degraded DNA samples as found in museum specimens. Using these methods could be useful in studying such groups as rodents of the genus Gerbillus for which i) the taxonomy is still highly debated, ii) collection of fresh specimens may prove difficult. Here we address precise taxonomic questions using a small portion of the cytochrome b gene obtained from 45 dry skin/skull museum samples (from 1913 to 1974) originating from two African and three Asian countries. The specimens were labelled Gerbillus gerbillus, Gerbillus andersoni, Gerbillus nanus, Gerbillus amoenus, Gerbillus perpallidus and Gerbillus pyramidum, and molecular results mostly confirmed these assignations. The close relationship between Gerbillus nanus (Asian origin) and Gerbillus amoenus (African origin) confirmed that they represent vicariant sibling species which differentiated in allopatry on either side of the Red Sea. In the closely related Gerbillus perpallidus and Gerbillus pyramidum, specimens considered as belonging to one Gerbillus pyramidum subspecies (Gerbillus pyramidum floweri) appeared closer to Gerbillus perpallidus suggesting that they (Gerbillus pyramidum floweri and Gerbillus perpallidus) may represent a unique species, distributed on both sides of the Nile River, for which the correct name should be Gerbillus floweri. Furthermore, the three other Gerbillus pyramidum subspecies grouped together with no apparent genetic structure suggesting that they may not yet represent genetically differentiated lineages. This study confirms the importance of using these methods on museum samples, which can open new perspectives in this particular group as well as in other groups of interest. PMID:27047247

  1. Ectoparasites of the critically endangered insular cavy, Cavia intermedia (Rodentia: Caviidae), southern Brazil

    PubMed Central

    Regolin, André Luis; Furnari, Nina; de Castro Jacinavicius, Fernando; Linardi, Pedro Marcos; de Carvalho-Pinto, Carlos José

    2015-01-01

    Cavia intermedia is a rodent species critically endangered and is found only on a 10 hectare island off the southern Brazilian coast. To identify the ectoparasites of C. intermedia, 27 specimens (14 males and 13 females), representing approximately 65% of the estimated total population, were captured and examined. A total of 1336 chewing lice of two species were collected: Gliricola lindolphoi (Amblycera: Gyropidae) and Trimenopon hispidum (Amblycera: Trimenoponidae). In addition, chiggers Arisocerus hertigi (Acari: Trombiculidae) and Eutrombicula sp. (Acari: Trombiculidae) were collected from the ears of all captured animals. This low species richness compared to those for other Cavia species is expected for island mammals. Although the results presented here are not conclusive about the relationship between C. intermedia and ectoparasites, this low species richness found might be reflected in a low level of investment by the hosts in the basal immune defense, since investments in white blood cell production by mammals are influenced by the diversity of parasites in the environment. Additionally, considering that it might result in host vulnerability to other parasites that might be introduced through exotic or migratory host species, the monitoring of C. intermedia, including parasitological and immunological assessments, is recommended as a key component of conservation efforts. PMID:25830106

  2. Karyological analysis of Proechimys cuvieri and Proechimys guyannensis (Rodentia, Echimyidae) from central Amazon

    PubMed Central

    e Silva, Carlos Eduardo Faresin; Eler, Eduardo Schmidt; da Silva, Maria Nazareth F.; Feldberg, Eliana

    2012-01-01

    The aim was to characterize the karyotype of rodents of the genus Proechimys from three localities in the central Brazilian Amazon, in the search for new markers that might shed light on our understanding of the taxonomy and evolutionary history of this taxon. Two karyotypes were found, viz., 2n = 28, FN = 46 in individuals from the NRSP (Cuieiras River) and REMAN (Manaus), and 2n = 46, FN = 50 in individuals from the Balbina Hydroelectric Plant. While individuals with the karyotype with 2n = 28 chromosomes were morphologically associated with Proechimys cuvieri, their karyotype shared similarities with those of the same diploid number in two other regions. Although three karyotypes are described for Proechimys cuvieri, no geographic distribution pattern that defined a cline could be identified. Based on the morphological examination of voucher specimens and additional results from molecular analysis, the karyotype with 2n = 46 and FN = 50 could be associated with P. guyannensis. PMID:22481879

  3. Molecular Diversity Within Melanomys caliginosus (Rodentia: Oryzomyini): Evidence for Multiple Species

    PubMed Central

    Hanson, J. Delton; Bradley, Robert D.

    2010-01-01

    Nucleotide sequences from the mitochondrial DNA cytochrome-b gene were used to infer phylogenetic relationships and estimate genetic distances from 10 individuals of Melanomys caliginosus and to explore the hypothesis that this taxon is comprised of multiple species. Individuals of four geographic populations of M. caliginosus from Central America (Nicaragua and Costa Rica), Panama, Venezuela, and Ecuador, respectively, were included in this analysis. Topologies obtained from maximum parsimony and Bayesian inference analyses were identical and produced clades referable to each of the geographic populations. Genetic distances between any pair-wise comparisons of the four groups (except between Panamanian and Venezuelan samples) were comparable to values estimated from comparisons of sister species in the closely related genus Nectomys. Distances between samples from Panama and Venezuela were greater than those of samples within the Ecuadorian and Central American clades, but less than that between species of Nectomys. Based on results from the sequence data, it appears that all four of the populations should be elevated to species level; however, additional data are needed to resolve the nomenclature of the Panamanian and Venezuelan populations. PMID:21614136

  4. The comparative gastrointestinal morphology of Jaculus jaculus (Rodentia) and Paraechinus aethiopicus (Erinaceomorpha).

    PubMed

    Pereira, Daniella L; Walters, Jacklynn; Bennett, Nigel C; Alagaili, Abdulaziz N; Mohammed, Osama B; Kotzé, Sanet H

    2016-05-01

    Jaculus jaculus (Lesser Egyptian jerboa) and Paraechinus aethiopicus (Desert hedgehog) are small mammals which thrive in desert conditions and are found, among others, in the Arabian Peninsula. Jaculus jaculus is omnivorous while P. aethiopicus is described as being insectivorous. The study aims to describe the gastrointestinal tract (GIT) morphology of these animals which differ in diet and phylogeny. The GITs of J. jaculus (n = 8) and P. aethiopicus (n = 7) were weighed, photographed, and the length, basal surface areas, and luminal surface areas of each of the anatomically distinct gastrointestinal segments were determined. The internal aspects of each area were examined and photographed while representative histological sections of each area were processed to wax and stained using haematoxylin and eosin. Both species had a simple unilocular stomach which was confirmed as wholly glandular on histology sections. Paraechinus aethiopicus had a relatively simple GIT which lacked a caecum. The caecum of J. jaculus was elongated, terminating in a narrow cecal appendix which contained lymphoid tissue on histological examination. The internal aspect of the proximal colon of J. jaculus revealed distinct V-shaped folds. Stomach content analysis of J. jaculus revealed mostly plant and seed material and some insects, whereas P. aethiopicus samples showed plant material in addition to insects, indicating omnivorous feeding tendencies in areas where insects may be scarce.

  5. Bony labyrinth morphometry indicates locomotor adaptations in the squirrel-related clade (Rodentia, Mammalia).

    PubMed

    Pfaff, Cathrin; Martin, Thomas; Ruf, Irina

    2015-06-22

    The semicircular canals (SCs) of the inner ear detect angular acceleration and are located in the bony labyrinth of the petrosal bone. Based on high-resolution computed tomography, we created a size-independent database of the bony labyrinth of 50 mammalian species especially rodents of the squirrel-related clade comprising taxa with fossorial, arboreal and gliding adaptations. Our sampling also includes gliding marsupials, actively flying bats, the arboreal tree shrew and subterranean species. The morphometric anatomy of the SCs was correlated to the locomotion mode. Even if the phylogenetic signal cannot entirely be excluded, the main significance for functional morphological studies has been found in the diameter of the SCs, whereas the radius of curvature is of minor interest. Additionally, we found clear differences in the bias angle of the canals between subterranean and gliding taxa, but also between sciurids and glirids. The sensitivity of the inner ear correlates with the locomotion mode, with a higher sensitivity of the SCs in fossorial species than in flying taxa. We conclude that the inner ear of flying and gliding mammals is less sensitive due to the large information flow into this sense organ during locomotion.

  6. Ecology of the interaction between Ixodes loricatus (Acari: Ixodidae) and Akodon azarae (Rodentia: Criceridae).

    PubMed

    Colombo, Valeria C; Nava, Santiago; Antoniazzi, Leandro R; Monje, Lucas D; Racca, Andrea L; Guglielmone, Alberto A; Beldomenico, Pablo M

    2015-10-01

    The present study explores associations of different factors (i.e. host parameters, presence of other ectoparasites and [mainly biotic] environmental factors) with burdens of Ixodes loricatus immature stages in one of its main hosts in Argentina, the rodent Akodon azarae. For 2 years, rodents were trapped and sampled monthly at 16 points located in four different sites in the Parana River Delta region. Data were analysed with generalized linear mixed models with a negative binomial response (counts of larvae or nymphs). The independent variables assessed were (a) environmental: trapping year, presence of cattle, type of vegetation, rodent abundance; (b) host parameters: body length, sex, body condition, blood cell counts, natural antibody titers and (c) co-infestation with other ectoparasites. Two-way interaction terms deemed a priori as relevant were also included in the analysis. Most of the associations investigated were found significant, but in general, the direction and magnitude of the associations were context-dependent. An exception was the presence of cattle, which was consistently negatively associated with both larvae and nymphs independently of all other variables considered and had the strongest effect on tick burdens. Mites, fleas and Amblyomma triste were also significantly associated (mostly positively) with larval and nymph burdens, and in many cases, they influenced associations with environmental or host factors. Our findings strongly support that raising cattle may have a substantial impact on the dynamics of I. loricatus and that interactions within the ectoparasite community may be an important-but generally ignored-driver of tick dynamics.

  7. Cryptic speciation and chromosomal repatterning in the South African climbing mice Dendromus (Rodentia, Nesomyidae).

    PubMed

    Solano, Emanuela; Taylor, Peter J; Rautenbach, Anita; Ropiquet, Anne; Castiglia, Riccardo

    2014-01-01

    We evaluate the intra- and interspecific diversity in the four South African rodent species of the genus Dendromus. The molecular phylogenetic analysis on twenty-three individuals have been conducted on a combined dataset of nuclear and mitochondrial markers. Moreover, the extent and processes underlying chromosomal variation, have been investigated on three species by mean of G-, C-bands, NORs and Zoo-FISH analysis. The molecular analysis shows the presence of six monophyletic lineages corresponding to D. mesomelas, D. mystacalis and four lineages within D. cfr. melanotis with high divergence values (ranges: 10.6% - 18.3%) that raises the question of the possible presence of cryptic species. The first description of the karyotype for D. mesomelas and D. mystacalis and C- and G- banding for one lineage of D. cfr. melanotis are reported highlighting an extended karyotype reorganization in the genus. Furthermore, the G-banding and Zoo-FISH evidenced an autosome-sex chromosome translocation characterizing all the species and our timing estimates this mutation date back 7.4 mya (Late Miocene). Finally, the molecular clock suggests that cladogenesis took place since the end of Miocene to Plio-Pleistocene, probably due to ecological factors, isolation in refugia followed by differential adaptation to the mesic or dry habitat.

  8. The evolution of bipedalism in jerboas (rodentia: Dipodoidea): origin in humid and forested environments.

    PubMed

    Wu, Shaoyuan; Zhang, Fuchun; Edwards, Scott V; Wu, Wenyu; Ye, Jie; Bi, Shundong; Ni, Xijun; Quan, Cheng; Meng, Jin; Organ, Chris L

    2014-07-01

    Mammalian bipedalism has long been thought to have arisen in response to arid and open environments. Here, we tested whether bipedalism coevolved with environmental changes using molecular and paleontological data from the rodent superfamily Dipodoidea and statistical methods for reconstructing ancestral characteristics and past climates. Our results show that the post-Late Miocene aridification exerted selective pressures on tooth shape, but not on leg length of bipedal jerboas. Cheek tooth crown height has increased since the Late Miocene, but the hind limb/head-body length ratios remained stable and high despite the environmental change from humid and forested to arid and open conditions, rather than increasing from low to high as predicted by the arid-bipedalism hypothesis. The decoupling of locomotor and dental character evolution indicates that bipedalism evolved under selective pressure different from that of dental hypsodonty in jerboas. We reconstructed the habitats of early jerboas using floral and faunal data, and the results show that the environments in which bipedalism evolved were forested. Our results suggest that bipedalism evolved as an adaptation to humid woodlands or forests for vertical jumping. Running at high speeds is likely a by-product of selection for jumping, which became advantageous in open environments later on.

  9. Re-evaluation of Sinocastor (Rodentia: Castoridae) with implications on the origin of modern beavers.

    PubMed

    Rybczynski, Natalia; Ross, Elizabeth M; Samuels, Joshua X; Korth, William W

    2010-11-15

    The extant beaver, Castor, has played an important role shaping landscapes and ecosystems in Eurasia and North America, yet the origins and early evolution of this lineage remain poorly understood. Here we use a geometric morphometric approach to help re-evaluate the phylogenetic affinities of a fossil skull from the Late Miocene of China. This specimen was originally considered Sinocastor, and later transferred to Castor. The aim of this study was to determine whether this form is an early member of Castor, or if it represents a lineage outside of Castor. The specimen was compared to 38 specimens of modern Castor (both C. canadensis and C. fiber) as well as fossil specimens of C. fiber (Pleistocene), C. californicus (Pliocene) and the early castorids Steneofiber eseri (early Miocene). The results show that the specimen falls outside the Castor morphospace and that compared to Castor, Sinocastor possesses a: 1) narrower post-orbital constriction, 2) anteroposteriorly shortened basioccipital depression, 3) shortened incisive foramen, 4) more posteriorly located palatine foramen, 5) longer rostrum, and 6) longer braincase. Also the specimen shows a much shallower basiocciptal depression than what is seen in living Castor, as well as prominently rooted molars. We conclude that Sinocastor is a valid genus. Given the prevalence of apparently primitive traits, Sinocastor might be a near relative of the lineage that gave rise to Castor, implying a possible Asiatic origin for Castor.

  10. Development and morphological changes in the vaginal closure membrane throughout gestation in Galea spixii (Rodentia: Caviidae).

    PubMed

    dos Santos, Amilton Cesar; Oliveira, Gleidson Benevides; Viana, Diego Carvalho; Oliveira, Franceliusa Delys; Silva, Renata dos Santos; Rici, Rose Eli Grassi; de Oliveira, Moacir Franco; de Assis-Neto, Antônio Chaves

    2016-05-01

    Present research was carried out in order to perform the monitoring of development, recognizes the type of tissue and describes histological and cellular changes of the vaginal closure membrane (VCM) throughout pregnancy in Galea spixii. The results showed that at 20 days of gestation (DG), the VCM occludes completely the external vaginal ostium. Microscopically, the VCM presented juxtaposed cells, derived from the stratum germinative of the stratified epithelium of vaginal mucosa at 20 DG and areas with cell clusters with the presence of intercellular spaces in the final stages of pregnancy (40-50 DG). At 0 DG, the stratified epithelium of vaginal mucosa presented all strata but at 20 DG presented stratified epithelium without the stratum corneum and stratum granular and showed communicant junctions by desmosomes and interdigitations in the cell membrane compound the VCM. Gradually from 40 to 50 DG the stratum germinative became barely perceptible. Many cells showed apoptotic nuclei and emerged many intercellular spacing. So, the interdigitations and desmosomes were not observed. Here, it was demonstrated for the first time that the VCM is formed after the extinction of the stratum granular and corneum of the vaginal mucosa epithelium, with the proliferation of the cells of stratum germinative and communication and junction through desmosomes and interdigitations of these cells. At the end of pregnancy, cellular apoptosis; the spread of stratum germinative; and, absence of cellular communication and junction may be responsible for the weakening of the VCM and may assist the process of rupture of this membrane.

  11. Taxonomic implications of morphological variation in three species of Trinomys (Rodentia: Echimyidae) from eastern Brazil.

    PubMed

    Dalapicolla, Jeronymo; Leite, Yuri L R

    2015-02-16

    Trinomys is a genus of terrestrial spiny rats from the Atlantic Forest, and three species occur in the state of Espírito Santo, eastern Brazil: T. gratiosus, T. paratus, and T. setosus. The levels of morphological variation within and among these species are virtually unknown, and their geographic ranges have not been properly assessed. These three species are externally very similar, hampering their identification in surveys and ecological studies that are not based on voucher specimens. We evaluated 162 specimens of Trinomys spp. from eastern Brazil, especially from the state of Espírito Santo, and used data from skulls, skins, and bacula to examine morphological variation and its taxonomic implications. We found extensive morphological variation in the skins and skulls even when diagnostic characters were examined, such as the number of dental lophs and bones contributing to the postorbital process. We also found variation in bacular shape among and within species, including polymorphism among individuals from the same population. The geographic range of each species in Espírito Santo was well defined: T. setosus occurred on the left (north) bank of the Doce River, and the other two species, T. gratiosus and T. paratus, occurred on the right (south) bank of this river; however, T. gratiosus was found at altitudes above 500 m, whereas T. paratus occurred below 580 m. Despite difficulties in species identification, the results of morphological and morphometric analyses are compatible with the current classification of these three species. In addition, the level of morphological variation found in specimens identified as T. g. panema--including types--falls within the range of T. g. gratiosus, confirming the taxonomic status of the former as a junior synonym of the latter.

  12. A new subspecies of hutia (Plagiodontia, Capromyidae, Rodentia) from southern Hispaniola.

    PubMed

    Turvey, Samuel T; Hansford, James; Kennerley, Rosalind J; Nuñez-Miño, José M; Brocca, Jorge L; Young, Richard P

    2015-05-14

    Continued uncertainty persists over the taxonomic status of many threatened Caribbean mammal populations. Recent molecular analysis has identified three genetically isolated allopatric hutia populations on Hispaniola that diverged during the Middle Pleistocene, with observed levels of sequence divergence interpreted as representing subspecies-level differentiation through comparison with genetic data for other capromyids. Subsequent analysis of existing museum specimens has demonstrated biogeographically congruent morphometric differentiation for two of these three populations, Plagiodontia aedium aedium (southwestern population) and P. aedium hylaeum (northern population). We report the first craniodental material for the southeastern Hispaniolan hutia population, and demonstrate that this population can also be differentiated using quantitative morphometric analysis from other Hispaniolan hutia subspecies. The holotype skull of P. aedium aedium, of unknown geographic provenance within Hispaniola, clusters morphometrically with the southwestern population. The southeastern Hispaniolan subspecies is described as Plagiodontia aedium bondi subsp. nov., and is assessed as Endangered under Criterion B1a,biii,v on the IUCN Red List.

  13. Mitochondrial phylogeny reveals cryptic genetic diversity in the genus Niviventer (Rodentia, Muroidea).

    PubMed

    He, Kai; Jiang, Xue-Long

    2015-02-01

    Niviventer is a muroid genus with 17 species widely distributed in East and Southeast Asia. These animals are important components of both extant and fossil small mammal communities, and they are among the most common infectious agents in humans. In this study, we employed partitioned Bayesian and relaxed clock divergence dating analyses and included the Niviventer mitochondrial cytochrome b genes of from GenBank (n = 223). Although the intra-generic relationships were not fully resolved, we recognized four major clades/subclades that could support further division of the genus. Paraphyletic and polyphyletic species were discovered, and 21 putative species were recognized through species delimitation analysis, which indicated an imperfect taxonomy and the existent of cryptic species. Molecular dating supported Niviventer origination in the late Miocene, and relatively higher diversification rates were observed in the late Pliocene and the Pleistocene, which might correlate with climate fluctuations.

  14. Gaudeamus lavocati sp. nov. (Rodentia, Hystricognathi) from the early Oligocene of Zallah, Libya: first African caviomorph?

    PubMed

    Coster, Pauline; Benammi, Mouloud; Lazzari, Vincent; Billet, Guillaume; Martin, Thomas; Salem, Mustafa; Bilal, Awad Abolhassan; Chaimanee, Yaowalak; Schuster, Mathieu; Valentin, Xavier; Brunet, Michel; Jaeger, Jean-Jacques

    2010-08-01

    A new African species of hystricognathous rodent, Gaudeamus lavocati sp. nov., is described herein from the early Oligocene deposits of Zallah locality (Sirt basin, Central Libya). The dental morphology of this species is very close to that of some earliest South American caviomorphs. It allows a reinterpretation of molar crest homologies among earliest caviomorphs, pentalophodonty being confirmed as the plesiomorphic molar condition in Caviomorpha. This morphological resemblance argues for close affinities between Gaudeamus and earliest South American hystricognaths. Cladistic analysis supports Gaudeamus lavocati sp. nov. as the first known African representative of Caviomorpha, implying that its ancestors were part of the African phiomyid group that crossed the South Atlantic by a direct immigration route. Alternatively, the series of derived dental features of Gaudeamus could also be interpreted as evolutionary synchronous convergences of an African hystricognath lineage towards the specialized pattern of some caviomorphs. However, the high level of similarities concerning teeth morphology and enamel microstructure and the similar age of fossiliferous strata on both continents make this interpretation less probable. The phylogenetic position of this taxon is of considerable importance because it represents an enigmatic component of the phiomorph-caviomorph radiation in Africa and appears as a new clue toward the understanding of caviomorph origins.

  15. Genetic diversity and population structure of the Guinea pig (Cavia porcellus, Rodentia, Caviidae) in Colombia

    PubMed Central

    Burgos-Paz, William; Cerón-Muñoz, Mario; Solarte-Portilla, Carlos

    2011-01-01

    The aim was to establish the genetic diversity and population structure of three guinea pig lines, from seven production zones located in Nariño, southwest Colombia. A total of 384 individuals were genotyped with six microsatellite markers. The measurement of intrapopulation diversity revealed allelic richness ranging from 3.0 to 6.56, and observed heterozygosity (Ho) from 0.33 to 0.60, with a deficit in heterozygous individuals. Although statistically significant (p < 0.05), genetic differentiation between population pairs was found to be low. Genetic distance, as well as clustering of guinea-pig lines and populations, coincided with the historical and geographical distribution of the populations. Likewise, high genetic identity between improved and native lines was established. An analysis of group probabilistic assignment revealed that each line should not be considered as a genetically homogeneous group. The findings corroborate the absorption of native genetic material into the improved line introduced into Colombia from Peru. It is necessary to establish conservation programs for native-line individuals in Nariño, and control genealogical and production records in order to reduce the inbreeding values in the populations. PMID:22215979

  16. [The influence of amplitude modulation on the structure of call spectrum in marmots (Marmota, rodentia, sciuridae)].

    PubMed

    Nikol'skiĭ, A A

    2007-01-01

    A relationship was established between the amplitude modulation and the structure of call spectrum in animals by the example of alarm call in three marmots (Marmota sibirica, M. menzbieri, and M. caudata). In the case of amplitude modulation, side frequencies are produced higher and lower than the carrier frequencies. In the absence of amplitude modulation, no side frequencies are produced.

  17. The geometry of the marmot (rodentia: sciuridae) mandible: phylogeny and patterns of morphological evolution.

    PubMed

    Cardini, Andrea

    2003-04-01

    Marmots have a prominent role in the study of mammalian social evolution, but only recently has their systematics received the attention it deserves if sociobiological studies are to be placed in a phylogenetic context. Sciurid morphology can be used as model to test the congruence between morphological change and phylogeny because sciurid skeletal characters are considered to be inclined to convergence. However, no morphological study involving all marmot species has ever been undertaken. Geometric morphometric techniques were applied in a comparative study of the marmot mandible. The adults of all 14 living marmot species were compared, and mean mandible shape were used to investigate morphological evolution in the genus Marmota. Three major trends were observed. First, the phylogenetic signal in the variation of landmark geometry, which describes mandible morphology, seems to account for the shape differences at intermediate taxonomic levels. The subgenera Marmota and Petromarmota, recently proposed on the basis of mitochondrial cytochrome b sequence, receive support from mandible morphology. When other sciurid genera were included in the analysis, the monophyly of the genus Marmota and that of the tribe Marmotini (i.e., marmots, prairie dogs, and ground squirrels) was strengthened by the morphological data. Second, the marmotine mandible may have evolved as a mosaic of characters and does not show convergence determined by size similarities. Third, allopatric speciation in peripheral isolates may have acted as a powerful force for modeling shape. This hypothesis is strongly supported by the peculiar mandible of M. vancouverensis and, to a lesser degree, by that of M. olympus, both thought to have originated as isolated populations in Pleistocene ice-free refugia.

  18. [Aberrations of the alarm call of the steppe marmot, Marmota bobak (Rodentia, Sciuridae)].

    PubMed

    Nikol'skiĭ, A A

    2008-01-01

    Aberrations, or deviations from the normal type of alarm call have been studied in the steppe marmot. One regular and several rare aberrations have been identified. The regular aberration manifests itself in all six populations studied, from the Kharkov Region in the west to the eastern border of the Orenburg Region in the east, with its frequency in the populations varying in different years from 10 to 66%. Rare aberrations occur sporadically and not in all populations.

  19. Arboreal locomotion in Eurasian harvest mice Micromys Minutus (Rodentia: Muridae): The gaits of small mammals.

    PubMed

    Karantanis, Nikolaos-Evangelos; Rychlik, Leszek; Herrel, Anthony; Youlatos, Dionisios

    2017-03-23

    Body size imposes significant constraints on arboreal locomotion. Despite the wealth of research in larger arboreal mammals, there is a lack of data on arboreal gaits of small mammals. In this context, the present study explores arboreal locomotion in one of the smallest rodents, the Eurasian harvest mice Micromys minutus (∼10 g). We examined gait metrics (i.e., diagonality, duty factor [DF], DF index, velocity, stride length, and stride frequency) of six adult male mice on simulated arboreal substrates of different sizes (2, 5, 10, and 25 mm) and inclinations (0(0) and 45(0) ). Micromys minutus employed slow, lateral sequence symmetrical gaits on the smaller substrates, which shifted to progressively faster symmetrical gaits of higher diagonality on larger substrates. Both ascents and descents were associated with a higher diagonality, and ascents with a higher DF index compared to horizontal locomotion, underscoring the role of the grasping hind feet. Velocity increase was brought about primarily by an increase in stride frequency, a pattern often encountered in other small mammals, with a secondary and significant contribution of stride length. These findings indicate that, except for velocity and the way it is regulated, there are no significant differences in gait metrics between larger and smaller arboreal mammals. Moreover, the locomotor adaptations of Eurasian harvest mice represent behavioral mechanisms that promote stable, safe, and continuous navigation along slender substrates and ultimately contribute to the successful exploitation of the arboreal milieu.

  20. [Comparative FISH analysis of C-positive regions of chromosomes of wood mice (Rodentia, Muridae, Sylvaemus)].

    PubMed

    Rubtsov, N B; Karamysheva, T V; Bogdanov, A S; Likhoshvaĭ, T V; Kartavtseva, I V

    2011-09-01

    The homology of DNA of C-positive centromeric regions of chromosomes in wood mice of the genus Sylvaemus (S. uralensis, S. fulvipectus, S. sylvaticus, S. flavicollis, and S. ponticus) was estimated for the first time. DNA probes were generated by microdissection from the centromeric regions of individual autosomes of each species, and their fluorescence in situ hybridization (FISH) with metaphase chromosomes of representatives of all studied wood mouse species was carried out. Unlike in the chromosomal forms and races of S. uralensis, changes in the DNA composition of the chromosomal centromeric regions in the wood mouse species of the genus Sylvaemus (including closely related S. flavicollis and S. ponticus) are both quantitative and qualitative. The patterns of FISH signals after in situ hybridization of the microdissection DNA probes with chromosomes of the species involved in the study demonstrate significant differences between C-positive regions of wood mouse chromosomes in the copy number and the level of homology of repetitive sequences as well as in the localization of homologous repetitive sequences. It was shown that C-positive regions of wood mouse chromosomes can contain both homologous and distinct sets of repetitive sequences. Regions enriched with homologous repeats were detected either directly in C-positive regions of individual chromosomes or only on the short arms of acrocentrics, or at the boundary of C-positive and C-negative regions.

  1. [Molecular genetic relationships among east Palearctic ground squirrels of the genus Spermophilus (Sciuridae, Rodentia)].

    PubMed

    Tsvirka, M V; Spiridonova, L N; Korablev, V P

    2008-08-01

    Genetic diversity in the four east Palearctic ground squirrel species of the genus Spermophilus--S. undulatus, S. parryi (subgenus Urocitellus), S. dauricus, and S. relictus (subgenus Citellus)--- was investigated using RAPD PCR with ten random primers. Siberian chipmunk, Tamias sibiricus, was used as an outgroup. Molecular markers for different taxonomic ranks were identified, including those for the genera Spermophilus and Tamias, subgenera Urocitellus and Citellus, as well as for each of the four species, S. undulatus, S. parryi, S. dauricus, and S. relictus. For the ground squirrel species and subgenera, genetic differentiation indices (H(t), H(s), D(st), G(st), Nm, and D) were calculated. In addition, for these groups the NJ phylogenetic reconstructions and UPGMA dendrograms of genetic similarity of the individuals and combined populations were constructed. Comparative molecular genetic analysis revealed a high genetic differentiation between S. undulates, S. dauricus, S. relicts, and S. parryi (G(st) = 0.58 to 0.82; D = 0.53 to 1.06), along with a low level of genetic differentiation of the subgenera Citellus and Urocitellus (G(st) = 0.33; D = 0.27), distinguished in accordance with the existing taxonomic systems of the genus Spermophilus.

  2. Digital dissection of the masticatory muscles of the naked mole-rat, Heterocephalus glaber (Mammalia, Rodentia).

    PubMed

    Cox, Philip G; Faulkes, Chris G

    2014-01-01

    The naked mole-rat, Heterocephalus glaber, of the family Bathyergidae is a subterranean rodent that feeds on underground roots and tubers and digs extensive tunnel systems with its incisors. It is a highly unusual mammal with regard to its social structure, longevity, pain insensitivity and cancer resistance, all of which have made it the subject of a great deal of research in recent years. Yet, much of the basic anatomy of this species remains undocumented. In this paper, we describe the morphology of the jaw-closing musculature of the naked mole-rat, as revealed by contrast-enhanced micro-computed tomography. This technique uses an iodine stain to enable the imaging of soft tissues with microCT. The iodine-enhanced scans were used to create 3D reconstructions of the naked mole-rat masticatory muscles from which muscle masses were calculated. The jaw-closing musculature of Heterocephalus glaber is relatively very large compared to other rodents and is dominated by the superficial masseter, the deep masseter and the temporalis. The temporalis in particular is large for a rodent, covering the entirety of the braincase and much of the rear part of the orbit. The morphology of the masseter complex described here differs from two other published descriptions of bathyergid masticatory muscles, but is more similar to the arrangement seen in other rodent families. The zygomaticomandibularis (ZM) muscle does not protrude through the infraorbital foramen on to the rostrum and thus the naked mole-rat should be considered protrogomorphous rather than hystricomorphous, and the morphology is consistent with secondarily lost hystricomorphy as has been previously suggested for Bathyergidae. Overall, the morphology of the masticatory musculature indicates a species with a high bite force and a wide gape-both important adaptations for a life dominated by digging with the incisors.

  3. Helminthes of synanthropic rodents (Rodentia: Muridae) from Dakahlia and Menoufia, Egypt.

    PubMed

    Elshazly, Atef M; Awad, Soha I; Azab, Manar S; Elsheikha, Hany M; Abdel-Gawad, Abdel Gawad E; Khalil, Hazem H M; Morsy, Tosson A

    2008-12-01

    A cross-sectional survey was conducted to monitor and compare the prevalence of helminthes in rodents from Dakahlia and Menoufia governorates. The domestic rodents (271) were Rattus norvegicus, Rattus rattus frugivorous, Rattus r. alexandrinus, & Mus musculus. The overall prevalence of helminthes was 52.8%. In Dakahlia, 72/145 rats (49.6%) were infected. The highest prevalence of infection was in R. r. frugivorous 43 (60.4%), then R. r. alexandrinus 44 (47.7%), R. norvegicus 38 (44.7%), and the lowest was M. musculus 20 (40%). In Menoufia, 71/126 rats (56.3%) were infected. The highest prevalence of infection was in R. r. frugivorous 36 (77.7%), then M. musculus 27 (48.1%), R. norvegicus 23 (47.8%), and the lowest was in R. r. alexandrinus 40 (47.5%). A total of 24 species of helminthes (11 trematodes, 4 cestodes & 10 nematodes) were identified among the 271 rodents. The commonest trematode was Mesostephanus aegypticus followed by Stictodora tridactyla. The commonest cestode was Hymenolepis diminuta followed by Taenia taeniaformis. The commonest nematode was Capillaria hepatica followed by Trichurus muris. Given the zoonotic potential of rodents' parasites and since several residential, commercial, and agricultural sites exist in the examined geographic areas, the potential health risk should not be ignored.

  4. Comparative study on the forefoot and hindfoot intrinsic muscles of some cavioidea rodents (Mammalia, Rodentia).

    PubMed

    Rocha-Barbosa, Oscar; Loguercio, Mariana F C; Renous, Sabine; Gasc, Jean-Pierre

    2007-01-01

    The present study compares the forefoot and hindfoot musculature of five representative species of Cavioidea rodents. In all species, the musculature of both forefeet and hindfeet have the same array regardless of the absence of digit I in the manus of Hydrochaeris hydrochaeris and Cavia porcellus. Our results suggest a tendency in these species towards a three-digit system, with a functional loss of digit V and a predominance of digit III in their forefeet. In the same way, the muscular reduction of digit I in the other rodents analyzed indicates a four-digit system with predominance of digit II in Myoprocta acouchy and Dasyprocta leporina and of digit V in Agouti paca. There seems to be an association between the muscular arrangement and functional axis of the foot, raising the general question why this axis runs between the third and forth digit, or along the third digit.

  5. Two new species of Hymenolepis (Cestoda: Hymenolepididae) from murid rodents (Rodentia: Muridae) in the Philippines.

    PubMed

    Makarikov, Arseny A; Tkach, Vasyl V; Bush, Sarah E

    2013-10-01

    Two previously unrecognized species of the genus Hymenolepis are described based on specimens obtained from murid rodent species Bullimus luzonicus , Apomys microdon , and Rattus everetti collected on Luzon Island, Philippines. Hymenolepis bicauda n. sp. differs from all known Hymenolepis spp. in relative position of the poral dorsal and ventral osmoregulatory canals, gravid uterus occupying less than half the length of proglottid, relatively few eggs, and the highly characteristic longitudinal split of proglottids at the end of the gravid strobila. Hymenolepis haukisalmii n. sp. differs from all known Hymenolepis spp. in the relative position of both poral and aporal dorsal and ventral osmoregulatory canals and uterus lacking dorsal and ventral diverticula. The shift in the relative position of the dorsal and ventral osmoregulatory canals was not known in Hymenolepis from rodents in other regions of the world and is reminiscent of the situation observed in Hymenolepis erinacei, parasitic in hedgehogs, and members of the genus Talpolepis, parasitic in moles. The cosmopolitan species Hymenolepis diminuta was the only member of the genus previously reported from the Philippines.

  6. Two new species of fossil Leggadina (Rodentia: Muridae) from Northwestern Queensland

    PubMed Central

    Godthelp, Henk

    2015-01-01

    Only three species of fossil murine have been described to date in Australia even though they are often found in fossil deposits and can be highly useful in understanding environmental change over time. Until now the genus Leggadina, a group of short-tailed mice that is particularly well adapted to an arid environment, was only known from two extant species: L. forresti and L. lakedownensis. Here two new fossil species of the genus are described from sites in northwestern Queensland. Leggadina gregoriensis sp. nov. comes from the Early Pleistocene Rackham’s Roost Site in the Riversleigh World Heritage Area and Leggadina macrodonta sp. nov. is from the Plio-Pleistocene Site 5C at Floraville Station. The evolution of the genus Leggadina and the lineage’s response to palaeoecological factors is considered. Taphonomy of the two fossil deposits is examined and shows marked differences in both faunal composition of the assemblages and preservation. Description of L. gregoriensis and L. macrodonta extends the known temporal range of the Leggadina lineage by over 2 million years. PMID:26207193

  7. Mitochondrial phylogeny of African wood mice, genus Hylomyscus (Rodentia, Muridae): implications for their taxonomy and biogeography.

    PubMed

    Nicolas, V; Quérouil, S; Verheyen, E; Verheyen, W; Mboumba, J F; Dillen, M; Colyn, M

    2006-03-01

    This paper investigates the usefulness of two mitochondrial genes (16S rRNA and cytochrome b) to solve taxonomical difficulties within the genus Hylomyscus and to infer its evolutionary history. Both genes proved to be suitable molecular markers for diagnosis of Hylomyscus species. Nevertheless the resolving powers of these two genes differ, and with both markers (either analyzed singly or in combination), some nodes remain unresolved. This is probably related to the fact that the species emerged during a rapid diversification event that occurred 2-6 Myr ago (4-5 Myr ago for most divergence events). Our molecular data support the recognition of an "aeta" group, while the "alleni" and "parvus" groups are not fully supported. Based on tree topology and genetic divergence, two taxa generally recognized as subspecies should be elevated at the species level (H. simus and H. cf kaimosae). H. stella populations exhibit ancient haplotype segregation that may represent currently unrecognized allopatric species. The existence of cryptic species within H. parvus is questioned. Finally, three potentially new species may occur in West Central Africa. The Congo and Oubangui Rivers, as well as the Volta and Niger Rivers and/or the Dahomey gap could have formed effective barriers to Hylomyscus species dispersal, favoring their speciation in allopatry. The pronounced shifts in African climate during the late Pliocene and Miocene, which resulted in major changes in the distribution and composition of the vegetation, could have promoted speciation within the genus (refuge theory). Future reports should focus on the geographic distribution of Hylomyscus species in order to get a better understanding of the evolutionary history of the genus.

  8. Glaciation Effects on the Phylogeographic Structure of Oligoryzomys longicaudatus (Rodentia: Sigmodontinae) in the Southern Andes

    PubMed Central

    Palma, R. Eduardo; Boric-Bargetto, Dusan; Torres-Pérez, Fernando; Hernández, Cristián E.; Yates, Terry L.

    2012-01-01

    The long-tailed pygmy rice rat Oligoryzomys longicaudatus (Sigmodontinae), the major reservoir of Hantavirus in Chile and Patagonian Argentina, is widely distributed in the Mediterranean, Temperate and Patagonian Forests of Chile, as well as in adjacent areas in southern Argentina. We used molecular data to evaluate the effects of the last glacial event on the phylogeographic structure of this species. We examined if historical Pleistocene events had affected genetic variation and spatial distribution of this species along its distributional range. We sampled 223 individuals representing 47 localities along the species range, and sequenced the hypervariable domain I of the mtDNA control region. Aligned sequences were analyzed using haplotype network, Bayesian population structure and demographic analyses. Analysis of population structure and the haplotype network inferred three genetic clusters along the distribution of O. longicaudatus that mostly agreed with the three major ecogeographic regions in Chile: Mediterranean, Temperate Forests and Patagonian Forests. Bayesian Skyline Plots showed constant population sizes through time in all three clusters followed by an increase after and during the Last Glacial Maximum (LGM; between 26,000–13,000 years ago). Neutrality tests and the “g” parameter also suggest that populations of O. longicaudatus experienced demographic expansion across the species entire range. Past climate shifts have influenced population structure and lineage variation of O. longicaudatus. This species remained in refugia areas during Pleistocene times in southern Temperate Forests (and adjacent areas in Patagonia). From these refugia, O. longicaudatus experienced demographic expansions into Patagonian Forests and central Mediterranean Chile using glacial retreats. PMID:22396751

  9. Fleas (Siphonaptera) in the Nests of Dormice (Gliridae: Rodentia) in Lithuania.

    PubMed

    Lipatova, I; Stanko, M; Paulauskas, A; Spakovaite, S; Gedminas, V

    2015-05-01

    Negative effects of flea (Siphonaptera) parasitism on the host may be expressed in different ways. The aim of this study was to assess distribution of the flea fauna in nests of dormice in Lithuania. Nests of Glis glis (L.), Dryomys nitedula (Pallas), and Muscardinus avellanarius (L.) were collected from nest boxes in 2012 and 2013. Fleas were collected from nests in the laboratory and put into plastic tubes with 70% ethanol. Flea species were identified using morphological keys. From 400 nest boxes, 112 nests of dormice were collected from eight sites from mixed forests of central Lithuania. Twenty-three nests of G. glis were collected from nest boxes, with 16 of them containing 286 fleas belonging to four species: Ceratophyllus sciurorum (Schrank) (259), C. gallinae (Schrank) (23), Hystrichopsylla talpae (Curtis) (3), and Megabothris turbidus (Rothschild) (1). Fourteen nests of M. avellanarius were collected from nest boxes, 4 of which contained 224 fleas belonging to two species: C. sciurorum (221) and C. gallinae (3). Twenty-four nests of D. nitedula were collected from nest boxes, including 17 containing 207 fleas belonging to two species: C. sciurorum (205) and C. gallinae (2). Fifty-one nests of undetermined dormice species also were collected from nest boxes, 12 of them contained 395 fleas belonging to three species: C. sciurorum (374), Ctenophthalmus agyrtes (Heller) (19), and Ctenophthalmus assimilis (Taschenberg) (2). C. sciurorum was a predominant species in the nests of dormice. The occurrence of C. gallinae was documented in Lithuania for the first time.

  10. Chromosome banding pattern in fat dormouse and bank vole (Mammalia: Rodentia) from Turkey.

    PubMed

    Arslan, Atilla; Zima, Jan; Yorulmaz, Tarkan; Gözütok, Serdar; Toyran, Kubilay

    2013-01-01

    The chromosome banding pattern (C-banding, AgNOR staining) was studied in isolated populations of two species of rodents from Turkey, Glis glis and Myodes glareolus. A single nucleolar organizer region was localized in an autosomal pair in the complement of G. glis. Centromeric C-heterochromatin blocks and seven pairs of NOR-bearing autosomes were observed in the complement of M. glareolus. A metacentric Y chromosome was found in the M. glareolus males examined. The detailed structure of karyotypes and the banding patterns differ from some previously published results.

  11. Bony labyrinth morphometry indicates locomotor adaptations in the squirrel-related clade (Rodentia, Mammalia)

    PubMed Central

    Pfaff, Cathrin; Martin, Thomas; Ruf, Irina

    2015-01-01

    The semicircular canals (SCs) of the inner ear detect angular acceleration and are located in the bony labyrinth of the petrosal bone. Based on high-resolution computed tomography, we created a size-independent database of the bony labyrinth of 50 mammalian species especially rodents of the squirrel-related clade comprising taxa with fossorial, arboreal and gliding adaptations. Our sampling also includes gliding marsupials, actively flying bats, the arboreal tree shrew and subterranean species. The morphometric anatomy of the SCs was correlated to the locomotion mode. Even if the phylogenetic signal cannot entirely be excluded, the main significance for functional morphological studies has been found in the diameter of the SCs, whereas the radius of curvature is of minor interest. Additionally, we found clear differences in the bias angle of the canals between subterranean and gliding taxa, but also between sciurids and glirids. The sensitivity of the inner ear correlates with the locomotion mode, with a higher sensitivity of the SCs in fossorial species than in flying taxa. We conclude that the inner ear of flying and gliding mammals is less sensitive due to the large information flow into this sense organ during locomotion. PMID:26019162

  12. [Feeding habits of the squirrel Sciurus variegatoides (Rodentia: Sciuridae) in the Nicoya Peninsula, Costa Rica].

    PubMed

    Monge, Javier; Hilje, Luko

    2006-06-01

    Food items consumed by the squirrel Sciurus variegatoides atrirufus were determined in an agricultural setting in the Nicoya Peninsula (9 degrees 47' N, 84 degrees 56' W), Costa Rica, where two life zones (Premontane Moist Forest Basal Belt Transition, and Tropical Dry Forest) predominate. By analyzing the gut contents of 120 squirrels, from February 1987 through January 1988, it was determined that coconut (Cocos nucifera), indian almond (Terminalia catappa) and flamboyant (Delonix regia) were the most common dietary items. There were differences in food consumption according to age: adults preferred coconut, whereas young individuals preferred almond. This finding can be explained in terms of fruit characteristics, as well as tree architecture and accessibility for squirrels; almendro trees provide higher protection and a more accessible food resource, so that it was better used by young individuals.

  13. Chromosomal and molecular characterization of Aethomys kaiseri from Zambia and Aethomys chrysophilus from Tanzania (Rodentia, Muridae).

    PubMed

    Castiglia, Riccardo; Corti, Marco; Colangelo, Paolo; Annesi, Flavia; Capanna, Ernesto; Verheyen, Walter; Sichilima, Alfred Matafwali; Makundi, Rhodes

    2003-01-01

    Aethomys is a common and widespread rodent genus in the African savannas and grasslands. However, its systematics and taxonomy are still unclear as no study has covered the entire range. In fact it might not be a monophyletic genus and perhaps should be split into two subgenera, Micaelamys and Aethomys. In this paper, we present findings based on the cytogenetics and the entire cytochrome b sequence of two species from Zambia (A. kaiseri) and Tanzania (A. chrysophilus), and we compare them with the sequences of a South African species (A. namaquensis) and other allied muroid genera. Comparison of the banded chromosomes revealed complete G-band homology between the autosomes of the two species. However, the X and Y chromosomes clearly differ in size and in C- and G-banding, being much larger in A. kaiseri. Comparison of the cytochrome b sequences places the separation between A. kaiseri and A. chrysophilus at 4.49 Mya, a period of intense speciation in other African muroids. The resulting phylogeny strongly supports the idea of a paraphyletic group, suggesting the need to elevate the previously described subgenera to the genus rank.

  14. Studies on Rift Valley fever in some African murids (Rodentia: Muridae).

    PubMed Central

    Swanepoel, R.; Blackburn, N. K.; Efstratiou, S.; Condy, J. B.

    1978-01-01

    Brains, spleens and livers of 2214 murids, 27 shrews and 7 dormice, trapped at 7 sites in Rhodesia, were tested in 277 pools for the presence of Rift Valley Fever virus. There were no isolations of Rift Valley Fever, but 69 isolations of an unidentified virus were obtained. Sixteen out of 867 sera had low-titre haemagglutination-inhibition activity against Rift Valley Fever antigen, but only one out of 1260 sera had neutralizing antibody. The evidence suggests that murids fail to encounter infection in nature and are unlikely to play a role in circulation and dissemination of Rift Valley Fever virus. Four out of seven widely distributed species of muried, Rhabdomys pumilio, Saccostomys campestris, Aethomys chrysophilus and Lemniscomys griselda, were shown to be capable of circulating amounts of virus likely to be infective for mosquitoes. PMID:632561

  15. Studies on Rift Valley fever in some African murids (Rodentia: Muridae).

    PubMed

    Swanepoel, R; Blackburn, N K; Efstratiou, S; Condy, J B

    1978-04-01

    Brains, spleens and livers of 2214 murids, 27 shrews and 7 dormice, trapped at 7 sites in Rhodesia, were tested in 277 pools for the presence of Rift Valley Fever virus. There were no isolations of Rift Valley Fever, but 69 isolations of an unidentified virus were obtained. Sixteen out of 867 sera had low-titre haemagglutination-inhibition activity against Rift Valley Fever antigen, but only one out of 1260 sera had neutralizing antibody. The evidence suggests that murids fail to encounter infection in nature and are unlikely to play a role in circulation and dissemination of Rift Valley Fever virus. Four out of seven widely distributed species of muried, Rhabdomys pumilio, Saccostomys campestris, Aethomys chrysophilus and Lemniscomys griselda, were shown to be capable of circulating amounts of virus likely to be infective for mosquitoes.

  16. WEST NILE VIRUS INFECTION IN TREE SQUIRRELS (RODENTIA: SCIURIDAE) IN CALIFORNIA, 2004–2005

    PubMed Central

    PADGETT, KERRY A.; REISEN, WILLIAM K.; KAHL-PURCELL, NICOLE; FANG, YING; CAHOON-YOUNG, BARBARA; CARNEY, RYAN; ANDERSON, NANCY; ZUCCA, LYNDA; WOODS, LESLIE; HUSTED, STAN; KRAMER, VICKI L.

    2007-01-01

    West Nile virus (WNV) transmission generally involves a mosquito vector and an avian reservoir host, with mammals as incidental hosts. Although most mammalian WNV infections cause low or no morbidity or mortality, tree squirrels are susceptible to WNV-associated neurologic disease with infection prevalence comparable to that in dead birds. Positive species included fox squirrel (Sciurus niger), western gray squirrel (S. griseus), and eastern gray squirrel (S. carolinensis). Kidney tissue (dissected and swabbed), and oropharyngeal (oral) swab samples from tree squirrels submitted by California vector control and rehabilitation agencies were tested by reverse transcription–polymerase chain reaction; cycle threshold values were similar for all three samples, ranging from 21.9 to 26.5. Kidney tissue was more sensitive than oral swabs for detecting WNV in squirrels. Three of 36 live neurologic tree squirrels had viremia approximately 5 log10 plaque-forming units/mL or greater, similar to WNV-infected birds. Tree squirrels are useful in WNV surveillance and provide localized evidence of WNV transmission to mammals. PMID:17488896

  17. Seasonal changes in burrow geometry of the common mole rat (Rodentia: Bathyergidae)

    NASA Astrophysics Data System (ADS)

    Thomas, H. G.; Scantlebury, M.; Swanepoel, D.; Bateman, P. W.; Bennett, N. C.

    2013-11-01

    Sociality in mole rats has been suggested to have evolved as a response to the widely dispersed food resources and the limited burrowing opportunities that result from sporadic rainfall events. In the most arid regions, individual foraging efficiency is reduced, and energetic constraints increase. In this study, we investigate seasonal differences in burrow architecture of the social Cryptomys hottentotus hottentotus in a mesic region. We describe burrow geometry in response to seasonal weather conditions for two seasons (wet and dry). Interactions occurred between seasons and colony size for the size of the burrow systems, but not the shape of the burrow systems. The fractal dimension values of the burrow systems did not differ between seasons. Thus, the burrow complexity was dependent upon the number of mole rats present in the social group.

  18. Evolution of Spatially Coexpressed Families of Type-2 Vomeronasal Receptors in Rodents

    PubMed Central

    Francia, Simona; Silvotti, Lucia; Ghirardi, Filippo; Catzeflis, François; Percudani, Riccardo; Tirindelli, Roberto

    2015-01-01

    The vomeronasal organ (VNO) is an olfactory structure for the detection of pheromones. VNO neurons express three groups of unrelated G-protein-coupled receptors. Type-2 vomeronasal receptors (V2Rs) are specifically localized in the basal neurons of the VNO and are believed to sense protein pheromones eliciting specific reproductive behaviors. In murine species, V2Rs are organized into four families. Family-ABD V2Rs are expressed monogenically and coexpress with family-C V2Rs of either subfamily C1 (V2RC1) or subfamily C2 (V2RC2), according to a coordinate temporal diagram. Neurons expressing the phylogenetically ancient V2RC1 coexpress family-BD V2Rs or a specific group of subfamily-A V2Rs (V2RA8-10), whereas a second neuronal subset (V2RC2-positive) coexpresses a recently expanded group of five subfamily-A V2Rs (V2RA1-5) along with vomeronasal-specific Major Histocompatibility Complex molecules (H2-Mv). Through database mining and Sanger sequencing, we have analyzed the onset, diversification, and expansion of the V2R-families throughout the phylogeny of Rodentia. Our results suggest that the separation of V2RC1 and V2RC2 occurred in a Cricetidae ancestor in coincidence with the evolution of the H2-Mv genes; this phylogenetic event did not correspond with the origin of the coexpressing V2RA1-5 genes, which dates back to an ancestral myomorphan lineage. Interestingly, the evolution of receptors within the V2RA1-5 group may be implicated in the origin and diversification of some of the V2R putative cognate ligands, the exocrine secreting peptides. The establishment of V2RC2, which probably reflects the complex expansion and diversification of family-A V2Rs, generated receptors that have probably acquired a more subtle functional specificity. PMID:25539725

  19. Effects of mitochondria-targeted plastoquinone derivative antioxidant (SkQ1) on demography of free-breeding Campbell dwarf hamsters (Phodopus campbelli) kept in outdoor conditions. reproduction and lifespan: explanation in the framework of ultimate loads.

    PubMed

    Rogovin, K A; Khrushcheva, A M; Shekarova, O N; Ushakova, M V; Manskikh, V N; Sokolova, O V; Vasilieva, N Yu

    2014-10-01

    We studied demographic effects of the mitochondria-targeted antioxidant SkQ1 on free-breeding Campbell dwarf hamsters (Phodopus campbelli, Thomas, 1905, Rodentia, Cricetidae) in an outdoor vivarium with seasonally varying day length and temperatures. The animals were kept in pairs from their young age. We removed litters from parental cages at their age of 25 days. Experimental hamsters received daily 50 nmol/kg SkQ1 with water by oral dosing, whereas control animals received water. SkQ1 had no effect on the lifespan of either males or females in reproductive pairs. Mortality among females was higher than among males irrespective of SkQ1 treatment, this being related to higher costs of reproduction in females. However, SkQ1 accelerated breeding in pairs in the first half of the reproductive period of a year. Although there were no statistical differences in body mass of males and females between experimental and control animals during most of their life, SkQ1-receiving males had higher body mass at the end of their life. The opposite tendency was characteristic for old females. One-year-old males and females of the experimental and control groups showed no difference in intensity of immune response to sheep red blood cells. The dermal hypersensitivity response to phytohemagglutinin (test for T-cell immunity) was significantly higher in SkQ1-treated 1- and 1.5-year-old males. This was not true for females. There was a tendency toward increased density of the neutrophil population in blood in 1-year-old SkQ1-treated males. However, experimental males showed no difference from control males in the activity of the "peroxidase-endogenous hydrogen peroxide system" of neutrophils. The background level of stress estimated by the concentration of cortisol in blood serum was significantly lower in the SkQ1-treated males during autumn adaptive adjustment of the organism. A similar trend was also observed during the January frosts, when the background level of stress was

  20. [Comparative FISH analysis of C-positive blocks of centromeric chromosomal regions of pygmy wood mice Sylvaemus uralensis (Rodentia, Muridae)].

    PubMed

    Karamysheva, T V; Bogdanov, A S; Kartavtseva, I V; Likhoshvaĭ, T V; Bochkarev, M N; Kolcheva, N E; Marochkina, V V; Rubtsov, N B

    2010-06-01

    The composition and homology of centromeric heterochromatin DNA has been compared in representatives of the Asian race and two chromosomal forms (Eastern European and Southern European) of the European race of the pygmy wood mouse Sylvaemus uralensis by means of in situ hybridization with metaphase chromosomes of microdissection DNA probes obtained from centromeric C-blocks of mice of the Southern European chromosomal form and the Asian race. Joint hybridization of both DNA probes yielded all possible variants of centromeric regions in terms of the presence of repetitive sequences homologous to those of some or another dissection region, which indicates a diversity of centromeric regions differing in DNA composition. However, most variations of the fluorescent in situ hybridization (FISH) patterns are apparently related to quantitative differences of repetitive elements of the genome. Experiments with the DNA probe obtained from the genome of the Southern European form of the pygmy wood mouse have shown that the number of intense FISH signals roughly corresponds to the number of large C-segments in representatives of the European race, which is characterized by a large amount of the centromeric C-heterochromatin in the karyotype. However, intense signals have been also detected in experiments on hybridization of this probe with chromosomes of representatives of the Asian race, which has no large C-blocks in the karyotype; thus, DNA sequences homologous to heterochromatic ones are also present in nonheterochromatic regions adjacent to C-segments. Despite the variations of the numbers of both intense and weak FISH signals, all chromosomal forms/races of S. uralensis significantly differ from one another in these characters. The number of intense FISH signals in DNA from the samples of pygmy wood mice from eastern Turkmenistan (the Kugitang ridge) and southern Omsk oblast (the vicinity of the Talapker railway station) was intermediate between those in the European and Asian races, which is apparently related to a hybrid origin of these populations (the hybridization having occurred long ago in the former case and recently in the latter case).

  1. Three new karyotypes extend a Robertsonian fan in Ethiopian spiny mice of the genus Acomys I. Geoffroy, 1838 (Mammalia, Rodentia).

    PubMed

    Lavrenchenko, L A; Nadjafova, R S; Bulatova, N Sh

    2011-01-01

    Three new karyotypes (2n=40, 44, 52) are described revealing what are probably new cryptic species of Ethiopian spiny mice. Two other diploid numbers have already been reported for the country (2n=36 and 68) and, overall, the five known karyotypic forms constitute a common lineage differentiated by a Robertsonian process. Such arrays of karyotypic forms are known as a 'Robertsonian fan'. This view of the situation in Ethiopian Acomys I. Geoffroy, 1838 is based on standard chromosomal morphology that reveals a constant FN (68) and needs further investigation of chromosome homology by differential staining and/or molecular cytogenetic techniques as well as further molecular phylogenetic analysis.

  2. Comparative gastrointestinal morphology of three small mammalian insectivores: Acomys spinosissimus (Rodentia), Crocidura cyanea (Eulipotyphla), and Amblysomus hottentotus (Afrosoricida).

    PubMed

    Boonzaier, Julia; Van der Merwe, Elizabeth L; Bennett, Nigel C; Kotzé, Sanet H

    2013-06-01

    The gastrointestinal morphology was investigated in three mammalian insectivorous species, namely Acomys spinosissimus, Crocidura cyanea, and Amblysomus hottentotus. The aim of the study was to provide a comprehensive morphological comparison between the different species and to explore whether anatomical gastrointestinal adaptations are associated with the insectivorous diet of these species. The shape, proportional length, and proportional surface areas of the different gastrointestinal regions were recorded and compared in the three insectivores. Hematoxylin and Eosin (H&E) and Alcian Blue/Periodic Acid Schiff (AB/PAS) were used for morphological assessment. In all three species, the stomach was simple and uncompartmentalized. The internal aspect of the stomach in A. spinosissimus was hemi-glandular, containing stratified squamous epithelium in the fundus, with glandular epithelium in the body and pyloric region. However, C. cyanea and A. hottentotus had wholly glandular stomachs. Paneth cells were not observed in the intestinal tracts of C. cyanea and A. hottentotus. Acomys spinosissimus was the only species studied that had a cecum. The proximal colonic region of A. spinosissimus had V-shaped mucosal folds. Histologically, C. cyanea had villi throughout the entire gastrointestinal tract (GIT), whereas for A. hottentotus villi were not present in the most distal gastrointestinal regions. In both C. cyanea and A. hottentotus, longitudinal mucosal folds were present in the distal part of the colon. The GITs of C. cyanea and A. hottentotus showed little morphological differentiation namely, a simple, glandular stomach and the lack of a cecum.

  3. Cytochrome b sequences reveal Acomys minous (Rodentia, Muridae) paraphyly and answer the question about the ancestral karyotype of Acomys dimidiatus.

    PubMed

    Barome, P O; Lymberakis, P; Monnerot, M; Gautun, J C

    2001-01-01

    Sequences of the cytochrome b (cyt b) mitochondrial gene show that the spiny mouse Acomys from Crete, known as the endemic species A. minous, is composed of two distinct maternal lineages ("A" and "B"). Group "A" sequences cluster with A. nesiotes (Cyprus) and group "B" sequences cluster with A. cilicicus (Turkey), which is evidence of paraphyly of A. minous in regard to these two species. From cyt b sequences, the three taxa are very closely related to A. cahirinus (Egypt): the maximum divergence found among these sequences is 1.6%, which is equivalent to the intraspecific diversity observed in other Acomys species. Paleozoology evidenced that man unintentionally introduced Acomys into Crete and Cyprus during antiquity. The divergence time between Acomys cyt b sequences found in Crete was estimated at 0.4 Myr, which means that the diversity observed did not appear after the introduction but reflects a much more ancient polymorphism. Cytochrome b phylogeny and cytogenetic data together comprise evidence that, within the species A. dimidiatus (Saudi Arabia, Israel, Egypt), it is the karyotypic form with 36 chromosomes that derives from the form with 38 chromosomes, due to a single acrocentric fusion.

  4. Three new karyotypes extend a Robertsonian fan in Ethiopian spiny mice of the genus Acomys I. Geoffroy, 1838 (Mammalia, Rodentia)

    PubMed Central

    Lavrenchenko, L.A.; Nadjafova, R.S.; Bulatova, N.Sh.

    2011-01-01

    Abstract Three new karyotypes (2n=40, 44, 52) are described revealing what are probably new cryptic species of Ethiopian spiny mice. Two other diploid numbers have already been reported for the country (2n=36 and 68) and, overall, the five known karyotypic forms constitute a common lineage differentiated by a Robertsonian process. Such arrays of karyotypic forms are known as a ‘Robertsonian fan’. This view of the situation in Ethiopian Acomys I. Geoffroy, 1838 is based on standard chromosomal morphology that reveals a constant FN (68) and needs further investigation of chromosome homology by differential staining and/or molecular cytogenetic techniques as well as further molecular phylogenetic analysis. PMID:24260646

  5. Historical biogeography at the crossroads of the northern continents: molecular phylogenetics of red-backed voles (Rodentia: Arvicolinae).

    PubMed

    Cook, Joseph A; Runck, Amy M; Conroy, Chris J

    2004-03-01

    Evolutionary relationships of red-backed voles and their relatives were examined and used to test biogeographic hypotheses. Sequences of the mitochondrial cytochrome b gene were obtained for 25 individuals representing Alticola macrotis, Clethrionomys californicus, C. gapperi, C. glareolus, C. rutilus, and C. rufocanus. These were combined with 21 partial sequences from GenBank for C. regulus, C. rex, C. rufocanus, C. rutilus, Eothenomys imaizumii, E. melanogaster, Phaulomys andersoni, and P. smithii. Complete sequences of three species of Microtus (M. montanus, M. oeconomus, and M. pennsylvanicus), representative species of other arvicoline genera (Myopus, Synaptomys, Arvicola, Ellobius, Ondatra, Lemmus, Dicrostonyx, and Phenacomys), and a sigmodontine representative (Peromyscus) were included as outgroups. We used maximum parsimony, maximum likelihood, distance, and Bayesian based methods and conducted statistical tests on proposed hypotheses of phylogenetic relationships and biogeographic histories. A close relationship of species representing the genera Alticola, Clethrionomys, and Eothenomys was supported (Clethrionomyini); however, the genus Clethrionomys was paraphyletic with respect to both Alticola and Eothenomys. Three major clades were identified as Asian (Eothenomys andersoni, E. smithii, C. rex, C. regulus, and C. rufocanus), Trans-beringian (Alticola macrotis, C. californicus, C. gapperi, C. glarelolus, and C. rutilus), and Taiwanese (E. melanogaster). These results are consistent with the fossil record which indicates an initial diversification in Asia followed by colonization of the Nearctic on at least two occasions. The holarctic species, C. rutilus, appears to have either reinvaded Asia from North America or colonized North America more recently (late Pleistocene) than the two species of Clethrionomys (C. gapperi and C. californicus) that are endemic to North America (early to mid-Pleistocene). Finally, C. gapperi, appears to be comprised of an eastern and a western species, the former with affinities to the Asian C. glareolus and the latter more closely related to C. californicus.

  6. Artificial life and speciation, a case study: heterochromatin and speciation in the Microtus savii Group (Rodentia-Arvicolinae).

    PubMed

    Cordelli, Alessandro; Cerrai, Paola; Galleni, Lodovico

    2003-01-01

    Artificial life is a tool which is used for simulation of peculiar cases of evolutionary events. The main characteristic of artificial life is that with this technique it is possible to simulate for a high number of generations the evolution of a population of individuals. Each individual is characterised by a small number of parameters, but each individual has its own evolutive story. So far it is possible to simulate the evolution of a population of some thousands specimens, for a high number of generations. The realistic aspect of the simulation is that each specimen is taken individually. In our opinion this instrument is very useful to simulate the evolution of the hybrids barrier during speciation. For this reason it is applied to a peculiar case of speciation, that of the Savi pine vole (Microtus savii) whose experimental data were recently investigated.

  7. X-Y chromosome synapsis and recombination in 3 vole species of Asian lineage of the genus Microtus (Rodentia: Arvicolinae).

    PubMed

    Borodin, P M; Basheva, E A; Dashkevich, O A; Golenishchev, F N; Kartavtseva, I V

    2011-01-01

    The pattern of X-Y chromosome pairing in male meiosis is an important taxonomic feature of grey voles of the genus Microtus. Asynaptic sex chromosomes have been found in the majority of species of the Palearctic phylogenetic lineage of this genus, while normal X-Y synapsis has been observed in the species of subgenus Pallasiinus belonging to the Asian phylogenetic lineage. We analyzed sex chromosome pairing and recombination in M. maximowiczii, M. mujanensis and M. fortis which also belong to the Asian phylogenetic lineage (subgenus Alexandromys). Using immunostaining for the proteins of the synaptonemal complex (SCP3) and recombination nodules (MLH1) we demonstrated that X and Y chromosomes of these species paired and recombined in a short subtelomeric region. This indicates that the sex chromosomes of these species retain an ancestral fully functional pseudoautosomal region, which has been lost or rearranged in the asynaptic species of the genus Microtus.

  8. Into Tibet: An Early Pliocene Dispersal of Fossil Zokor (Rodentia: Spalacidae) from Mongolian Plateau to the Hinterland of Tibetan Plateau

    PubMed Central

    Li, Qiang; Wang, Xiaoming

    2015-01-01

    This paper reports the fossil zokors (Myospalacinae) collected from the lower Pliocene (~4.4 Ma) of Zanda Basin, southwestern Tibet, which is the first record in the hinterland of Tibetan Plateau within the Himalayan Range. Materials include 29 isolated molars belonging to Prosiphneus eriksoni (Schlosser, 1924) by having characters including large size, highly fused roots, upper molars of orthomegodont type, m1 anterior cap small and centrally located, and first pair of m1 reentrants on opposing sides, high crowns, and high value of dentine tract parameters. Based on the cladistics analysis, all seven species of Prosiphneus and P. eriksoni of Zanda form a monophyletic clade. P. eriksoni from Zanda, on the other hand, is nearly the terminal taxon of this clade. The appearance of P. eriksoni in Zanda represents a significant dispersal in the early Pliocene from its center of origin in north China and Mongolian Plateau, possibly via the Hol Xil-Qiangtang hinterland in northern Tibet. The fast evolving zokors are highly adapted to open terrains at a time when regional climates had become increasingly drier in the desert zones north of Tibetan Plateau during the late Miocene to Pliocene. The occurrence of this zokor in Tibet thus suggests a rather open steppe environment. Based on fossils of large mammals, we have formulated an “out of Tibet” hypothesis that suggests earlier and more primitive large mammals from the Pliocene of Tibet giving rise to the Ice Age megafauna. However, fossil records for large mammals are still too poor to evaluate whether they have evolved from lineages endemic to the Tibetan Plateau or were immigrants from outside. The superior record of small mammals is in a better position to address this question. With relatively dense age intervals and numerous localities in much of northern Asia, fossil zokors provide the first example of an “into Tibet” scenario–earlier and more primitive taxa originated from outside of the Tibetan Plateau and the later the lineage became extinct in southwestern Tibet. PMID:26658457

  9. Population dynamics and bioenergetics of a fossorial herbivore, Thomomys talpoides (Rodentia: Geomyidae), in a spruce-fir sere

    USGS Publications Warehouse

    Andersen, Douglas C.; MacMahon, James A.

    1981-01-01

    Studies of the bioenergetics of the northern pocket gopher, Thomomys talpoides, are coupled with data on demography, activity budgets, and microclimates to model the energy requirements of individuals and populations in the Wasatch Mountains of Utah during 1976-1979. Metabolic rates during rest increased linearly with decreasing ambient temperature, but burrowing metabolic rates (16.3 mL O2 • h-1 • g-9.75) were independent of both temperature and physical properties of the soil. Radio-telemetry studies indicated that free-ranging gophers are active =50% of each day. Conservative estimates of true energy consumption were calculated using estimates of habitat-specific minimum daily burrowing requirements. Rates of burrowing measured in the laboratory were either ∞ 0.0 or ∞ 2.0 cm/min. The low burrowing rate was observed when the soil was frozen or saturated with water, as would occur in the field in early winter and in spring, respectively. Gophers burrowed through soil at the study site at an average rate of ∞ 1.5 cm/min. Belowground food energy densities at gopher foraging depth declined from 24.6 to 3.2 J/cm3 along a successional gradient (subalpine forb meadow to Engelmann spruce dominated forest). We conclude that individual gophers are food limited within the climax spruce seral stage. Further, daily energy costs associated with reproduction in females may exceed the belowground energy supply available in intermediate seral stages (aspen and subalpine fir). Reduction of burrowing rates for any reason will affect gophers in the late seral stages proportionately more than those resident in the meadow. The peak gopher densities recorded (from 62 individuals/ha in the meadow to 2 individuals/ha in spruce forest) support these inferences. Detailed demographic information was obtained only in the meadow seral stage. Adult survivorship was lower in winter than in summer and varied greatly between years (0.18-0.70 yr-1). Juvenile survivorship from weaning through the first year was comparable to adult annual rates. The fertility rate was 3.75 young • female-1 • yr-1. The energy supply and demand analyses indicate that the growth of Thomomys talpoides populations in the early seral stages is seldom directly limited by the amount of food present. From our demographic, environmental, and autecological studies we conclude that stochastic events associated with weather affect energy acquisition (burrowing) rates, and thus survivorship. In montane environments, such events may prevent populations from attaining sizes at which territorial behavior would hypothetically limit further increases. The energy flow through the meadow population at moderate to high )1976-1977) densities (at least 1100 MJ • ha-1 • yr-1) indicates that pocket gophers are proficient energy movers relative to non-fossorial small mammals. Subalpine T. talpoides populations appear commonly to attain such densities. More than 30% of the annual primary productivity allocated to belowground parts of meadow forbs may be consumed by gophers.

  10. In the wake of invasion: tracing the historical biogeography of the South American cricetid radiation (Rodentia, Sigmodontinae).

    PubMed

    Leite, Rafael N; Kolokotronis, Sergios-Orestis; Almeida, Francisca C; Werneck, Fernanda P; Rogers, Duke S; Weksler, Marcelo

    2014-01-01

    The Great American Biotic Interchange (GABI) was greatly influenced by the completion of the Isthmus of Panama and impacted the composition of modern faunal assemblages in the Americas. However, the contribution of preceding events has been comparatively less explored, even though early immigrants in the fossil records are evidence for waif dispersals. The cricetid rodents of the subfamily Sigmodontinae are a classic example of a species-rich South American radiation resulting from an early episode of North American invasion. Here, we provide a temporal and spatial framework to address key aspects of the historical biogeography and diversification of this diverse mammal group by using mitochondrial and nuclear DNA datasets coupled with methods of divergence time estimation, ancestral area reconstruction and comparative phylogenetics. Relaxed-clock time estimates indicate that divergence of the Sigmodontinae began in the middle-late Miocene (ca. 12-9 Ma). Dispersal-vicariance analyses point to the arrival of a single lineage of northern invaders with a widespread ancestral distribution and imply that the initial differentiation between Central and South America gave rise to the most basal groups within the subfamily. These two major clades diversified in the late Miocene followed by the radiation of main tribes until the early Pliocene. Within the Oryzomyalia, tribes diverged initially in eastern South America whereas multiple dispersals into the Andes promoted further diversification of the majority of modern genera. A comparatively uniform background tempo of diversification explains the species richness of sigmodontines across most nodes, except for two akodontine genera with recent increases in diversification rates. The bridging of the Central American seaway and episodes of low sea levels likely facilitated the invasion of South America long before the onset of the post-Isthmian phase of the GABI.

  11. Napoleon Bonaparte and the fate of an Amazonian rat: new data on the taxonomy of Mesomys hispidus (Rodentia: Echimyidae).

    PubMed

    Orlando, Ludovic; Mauffrey, Jean-François; Cuisin, Jacques; Patton, James L; Hänni, Catherine; Catzeflis, François

    2003-04-01

    The spiny rat Mesomys hispidus is one of many South American rodents that lack adequate taxonomic definition. The few sampled populations of this broadly distributed trans-Amazonian arboreal rat have come from widely separated regions and are typically highly divergent. The holotype was described in 1817 by A.-G. Desmarest, after Napoleon's army brought it to Paris following the plunder of Lisbon in 1808; however, the locality of origin has remained unknown. Here we examine the taxonomic status of this species by direct comparison of 50 extant individuals with the holotype at the morphometric and genetic levels, the latter based on 331 bp of the mitochondrial cytochrome b gene retrieved from a small skin fragment of the holotype with ancient DNA technology. Extensive sequence divergence is present among samples of M. hispidus collected from throughout its range, from French Guiana across Amazonia to Bolivia and Peru, with at least seven mitochondrial clades recognized (average divergence of 7.7% Kimura 2-parameter distance). Sequence from the holotype is, however, only weakly divergent from those of recent samples from French Guiana. Moreover, the holotype clusters with greater that 99% posterior probability with samples from this part of Amazonia in a discriminant analysis based on 22 cranial and dental measurements. Thus, we suggest that the holotype was originally obtained in eastern Amazonia north of the Amazon River, most likely in the Brazilian state of Amapá. Despite the high level of sequence diversity and marked morphological differences in size across the range of M. hispidus, we continue to regard this assemblage as a single species until additional samples and analyses suggest otherwise.

  12. Comparative chromosome painting map between two Ryukyu spiny rat species, Tokudaia osimensis and Tokudaia tokunoshimensis (Muridae, Rodentia).

    PubMed

    Nakamura, Taro; Kuroiwa, Asato; Nishida-Umehara, Chizuko; Matsubara, Kazumi; Yamada, Fumio; Matsuda, Yoichi

    2007-01-01

    Ryukyu spiny rats (genus Tokudaia) are indigenous species that are confined to three islands of the Nansei Shoto archipelago, Amami-Oshima, Tokunoshima and Okinawa-jima, Japan. Tokudaia tokunoshimensis from Tokunoshima Island and Tokudaia osimensis from Amami-Oshima Island are closely related taxonomically, although their karyotypes are quite different: the diploid chromosome numbers and sex chromosome constitution are 2n=45, X0/X0 for T. tokunoshimensis and 2n=25, X0/X0 for T. osimensis. We conducted comparative chromosome painting with chromosome-specific DNA probes of the laboratory mouse (Mus musculus) to molecularly examine the chromosome homology between T. tokunoshimensis and T. osimensis, and deduced a possible ancestral karyotype of Tokudaia species and the process of evolutionary chromosome rearrangements. The proposed ancestral karyotype with the diploid number of 2n=48, XX/XY was similar to the karyotype of T. tokunoshimensis, and the karyotype of T. osimensis would then have been established through at least 14 chromosomal changes, mainly centric fusion and tandem fusion, from the ancestral karyotype. The close karyological relationship between the ancestral karyotypes of Tokudaia and Apodemus also suggests that the chromosomal evolution in the Tokudaia-Apodemus lineage has been very slow and has accelerated only recently in the branch leading to T. osimensis.

  13. Establishment of Orientia tsutsugamushi Lc-1 (Rickettsiales: Rickettsiaceae) infection in ICR outbred mice (Rodentia: Muridae) by needle challenge.

    PubMed

    Lurchachaiwong, Woradee; Chan, Teik-Chye; Richards, Allen L; McCardle, Wesley; Schuster, Anthony L

    2014-05-01

    Orientia tsutsugamushi is a pathogen transmitted by Leptotrombidium that causes scrub typhus. To develop an infection mouse model, a mite-derived isolate of O. tsutsugamushi was established from a laboratory-maintained colony of Leptotrombidium chiangraiensis (O. tsutsugamushi Lc-1). This Lc-1 isolate was initially presented to ICR (CD-1) mice by feeding an infected Lc chigger on the ear of a mouse. Once the Lc-1 was adapted to the ICR mice, quantitative real-time polymerase chain reaction was used to investigate O. tsutsugamushi genomic equivalent copies in tissues and sera. Furthermore, times to onset of the signs of infection are reported in this study. This study provides information useful for future research on this host-pathogen interaction and the associated vaccine efficacy trials.

  14. Trypanosoma cruzi: distinct patterns of infection in the sibling caviomorph rodent species Thrichomys apereoides laurentius and Thrichomys pachyurus (Rodentia, Echimyidae).

    PubMed

    Roque, André Luiz Rodrigues; D'Andrea, Paulo Sérgio; de Andrade, Gisele Braziliano; Jansen, Ana Maria

    2005-09-01

    Thrichomys apereoides, a caviomorph rodent species common in a highly endemic area for Chagas disease in Brazil, may act as reservoir of the parasite. However, no information is available concerning its sibling species Thrichomys pachyurus, found in the Pantanal region, where Trypanosoma cruzi is found only in the enzootic cycle. We followed up the cross infection of these cryptic species with two isolates derived from naturally infected T. pachyurus and Thrichomys apereoides laurentius. No regional co-adaptation between Thrichomys species and the regional isolates were noticed. However, significant differences in the outcome of the infection were observed. T. a. laurentius was more resistant than T. pachyurus, as expressed by lower parasitemia and less histopathological damage. The routine biochemical markers used for laboratory rodents were unsuitable for follow up of infection in Thrichomys spp, since they did not correlate with the histopathological findings or allowed the kinetic follow-up of tissue colonization by the parasite.

  15. Syphacia obvelata (Nematode, Oxyuridae) infecting laboratory mice Mus musculus (Rodentia, Muridae): phylogeny and host-parasite relationship.

    PubMed

    Abdel-Gaber, Rewaida

    2016-03-01

    Syphacia obvelata is a pinworm nematode parasite infecting man and laboratory animals in high abundance. This parasitological study was carried out during the period of March 2014-February 2015 to investigate the helminth parasites infecting the laboratory mice Mus musculus in the Animal House at Cairo University, Egypt. The prevalence of S. obvelata in M. musculus was 75.0 %. The extent of infection with S. obvelata is analyzed according to the sex of the host mice. It was shown that the prevalence of male infection was greater than female worms. Morphological characterization revealed that the present Oxyurid species possesses a rounded cephalic end with less developed lips, esophagus divided into cylindrical corpus, and globular bulb supported internally with valvular apparatus; three mamelons are located at the ventral surface with a single chitinized spicule and a gubernaculum provided with an accessory hook in males, and ovijector apparatus opens ventrally by the vulva surrounded by protruded lips in female worms. Body of the male was 0.623-1.130 (0.830 ± 0.11) mm long and 0.092-0.130 (0.110 ± 0.01) mm wide; the esophagus was 0.164-0.280 (0.210 ± 0.01) mm long; the nerve ring and excretory pore are located at 0.035-0.132 (0.073 ± 0.01) and 0.087-0.191 (0.145 ± 0.01) mm from the anterior end, respectively, while the female measured 2.930-4.650 (3.540 ± 0.1) mm long and 0.120-0.232 (0.156 ± 0.001) mm wide; the esophagus was 0.213-0.410 (0.342 ± 0.01) mm long; the nerve ring, excretory pore, and vulval opening are located at 0.026-0.157 (0.121 ± 0.01), 0.134-0.243 (0.195 ± 0.01), and 0.323-0.632 (0.546 ± 0.11) mm from the anterior end, respectively; eggs measured 0.120-0.139 (0.129 ± 0.001) mm long and 0.030-0.052 (0.045 ± 0.001) mm wide. It compared morphometrically with other Syphacia species described previously and showed little differences in measurements. Molecular characterization based on small subunit ribosomal DNA (rDNA) was done to confirm the obtained morphological and morphometric results. A preliminary genetic comparison between SSU rDNA of the present parasite and other species of Oxyuridae places it as a putative sister taxon to other S. obvelata.

  16. A new genus of aplodontid rodent (Mammalia, Rodentia) from the late Oligocene of northern Junggar Basin, China.

    PubMed

    Bi, Shundong; Meng, Jin; McLean, Sarah; Wu, Wenyu; Ni, Xijun; Ye, Jie

    2013-01-01

    A new genus and species of aplodontid rodent, Proansomys dureensis, from the late Oligocene of the northern Junggar Basin of China is described. The new genus is referred to as Ansomyinae because the ectoloph on the upper cheek teeth, although not fully crested, has attained the same characteristic bucket-handle-shaped configuration as other members of the subfamily. It represents the earliest record of the subfamily yet discovered in Asia and is more plesiomorphic than species of the genus Ansomys in having a partly crested ectoloph, a lower degree of lophodonty, and less complex tooth basins (lacking accessory lophules). Proansomys has transitional features between Prosciurus and Ansomys, suggesting that the Ansomyinae derived from a group of aplodontids related to Prosciurus, as did other advanced aplodontid rodents. This provides new light on the paleobiogeography of the Ansomyinae.

  17. Genetic and morphological variability in South American rodent Oecomys (Sigmodontinae, Rodentia): evidence for a complex of species.

    PubMed

    Rosa, C C; Flores, T; Pieczarka, J C; Rossi, R V; Sampaio, M I C; Rissino, J D; Amaral, P J S; Nagamachi, C Y

    2012-01-01

    The rodent genus Oecomys (Sigmodontinae) comprises ~16 species that inhabit tropical and subtropical forests in Central America and South America. In this study specimens of Oecomys paricola Thomas, 1904 from Belém and Marajó island, northern Brazil, were investigated using cytogenetic, molecular and morphological analyses. Three karyotypes were found, two from Belém (2n = 68, fundamental number (FN) = 72 and 2n = 70, FN = 76) and a third from Marajó island (2n = 70, FN = 72). No molecular or morphological differences were found between the individuals with differing cytotypes from Belém, but differences were evident between the individuals from Belém and Marajó island. Specimens from Belém city region may represent two cryptic species because two different karyotypes are present in the absence of significant differences in morphology and molecular characteristics. The Marajó island and Belém populations may represent distinct species that have been separated for some time, and are in the process of morphological and molecular differentiation as a consequence of reproductive isolation at the geographic and chromosomal levels. Thus, the results suggest that O. paricola may be a complex of species.

  18. Karyotype reorganisation in the subtilis group of birch mice (Rodentia, Dipodidae, Sicista): unexpected taxonomic diversity within a limited distribution.

    PubMed

    Kovalskaya, Y M; Aniskin, V M; Bogomolov, P L; Surov, A V; Tikhonov, I A; Tikhonova, G N; Robinson, T J; Volobouev, V T

    2011-01-01

    Conventional cytogenetic studies of Sicista subtilis and S. severtzovi (Dipodidae, Sicistinae), both attributable to the subtilis group of birch mice, revealed extensive karyotype diversity with 2n = 16-26 and NFa values of 26-46 indicating the overwhelming non-Robertsonian nature of chromosomal reorganization in these species. The numerical and structural chromosome variability was principally found in specimens located within a confined region of the East European (Russian) Plain. The approximately 135,000-km(2) area occurs in the vicinity of the Don River bend between 49°13'N/43°46'E and 51°32'N/36°16'E. The detection of cytotypes sharing similar 2n and NF values, but having morphologically distinct chromosomes, suggests that these may result from polymorphisms present both within recognized species and in cryptic taxa not hitherto described. We conducted a comprehensive, comparative chromosome banding analysis of 52 birch mice (21 localities) referable to the subtilis group and report the presence of 5 distinct karyotypes, each characterized by a combination of stable, variable, and partly overlapping 2n/NFa values. These karyotypes differed from each other by 10-29 structural chromosomal rearrangements (18.1 ± 6.3) that comprised Rb fusions/fissions (42.2%), pericentric inversions (31.1%), and tandem translocations (22.2%). The composition, and the high numbers of these chromosomal changes, is likely to provide an effective means of post-mating isolation, suggesting that taxonomic diversity within the subtilis group is larger than currently accepted. Additionally, we report the frequent fixation of tandem translocations in sample populations, one of which was found in a polymorphic state representing, as far as we are aware, the first case of an in statu nascendi tandem fusion in wild populations. Moreover, our data revealed that bi-armed chromosomes were involved in fusions detected in some of the subtilis taxa. In each instance, however, fusions were preceded by pericentric inversions that transform one or both bi-armed chromosomes into acrocentrics resulting in either centromere-telomere or Robertsonian translocations. Finally, a phylogenetic scenario inferred from a cladistic analysis of the chromosomal data suggests that the extensive karyotypic diversification within the subtilis group in the south-east region of the Russian Plain most likely results from fragmentation of a continuously distributed, ancestral population. It is thought that this occurred at the last glacial maximum (18,000-14,000 years B.P.), and that the process of isolation has been exacerbated by increasing human activity in the region in modern times.

  19. Distribution and habitat of the Laotian Rock Rat Laonastes aenigmamus Jenkins, Kilpatrick, Robinson & Timmins, 2005 (Rodentia: Diatomyidae) in Vietnam

    PubMed Central

    Nguyen, Nghia Xuan; Nguyen, Duy Dinh; Dinh, Tri Huy; Le, Dinh Thuc; Dinh, Duong Hai

    2014-01-01

    Abstract The Laotian Rock Rat Laonastes aenigmamus Jenkins, Kilpatrick, Robinson & Timmins, 2005 was originally discovered in Lao People's Democratic Republic in 2005. This species has been recognized as the sole surviving member of the otherwise extinct rodent family Diatomyidae. Laonastes aenigmamus was initially reported only in limestone forests of Khammouane Province, Central Lao. A second population was recently discovered in Phong Nha Ke Bang National Park (PNKB NP), Quang Binh Province, Central Vietnam in 2011. The confirmed distribution range of L. aenigmamus in Vietnam is very small, approximately 150 km2, covering low karst mountains in five communes of Minh Hoa District, Quang Binh Province, at elevations between 250 and 400 m asl. The Laotian Rock Rat inhabits the lower part of steep karst towers with many rock boulders and crevices under tall limestone evergreen forest. They use small rock crevices for their dens. The natural habitat of this species in PNKB NP has been affected by selected timber harvesting, however, a complex 3-4 layer forest structure is retained. The Laotian Rock Rat is omnivorous, feeding on parts (leaves, buds, fruits and roots) of 18 plant species and also some insects (cicada, mantis, grasshopper). The population of this species in PNKB NP is seriously threatened with extinction due to its very restricted distribution, high hunting pressure, and habitat disturbance. Laonastes aenigmamus is listed in the IUCN Red List as endangered and in the Wildlife and Aquatic Red List of Lao, however, this species has not been listed in the Red Data Book or any conservation legislative documents of Vietnam. PMID:25589873

  20. [Diet of the capybara Hydrochaeris hydrochaeris (Rodentia: Hydrocharidae) in Caño Limón, Arauca, Colombia].

    PubMed

    Forero-Montaña, Jimena; Betancur, Julio; Cavelier, Jaime

    2003-06-01

    We studied the composition and seasonal variation of the diet of the capybara (Hydrochaeris hydrochaeris) in the flooded savannas of Caño Limón, Colombia. This was achieved by direct observation of the consumption patterns of these animals. The capybaras only consumed plants, and their diet included 89 species of 22 families. Sixty three percent of these plant species had not been reported before. The most commonly consumed plants (94% of the diet), belonged to the Poaceae, Cyperaceae, Leguminosae and Pontederiaceae. Only seven species represented 60% of the total diet: the grasses Hymenachne amplexicaulis (16.9%), Digitaria bicornis (4.5%) and Panicum maximum (4.4%) and the Cyperaceae Rynchospora corymbosa (4.4%). There was seasonal variation in the diet composition of capybaras.

  1. First record of Mylagaulid rodents (Rodentia, Mammalia) from the Miocene of Eastern Siberia (Olkhon Island, Baikal Lake, Irkutsk Region, Russia).

    PubMed

    Tesakov, A S; Lopatin, A V

    2015-01-01

    A new genus and species of rodent, Lamugaulus olkhonensis, belonging to the subfamily Promylagaulinae of the family Mylagaulidae, is described on the basis of isolated teeth from the Khalagay Formation of the Lower Miocene Tagay locality (Olkhon island, Lake Baikal, Irkutsk Region). This is the first record of mylagaulids in Eastern Siberia, significantly expanding the data on the distribution of this mainly North American group of rodents in Asia and showing its presence outside the Central Asian arid zone.

  2. Redescription of Echinocoleus hydrochoeri (Travassos, 1916) (Nematoda: Trichuridae) from Hydrochoeris hydrochaeris Linnaeus, 1766 (Rodentia: Caviidae) from Argentina.

    PubMed

    Robles, María del Rosario; Eberhardt, María Ayelen Teresita; Bain, Odile; Beldomenico, Pablo Martín

    2013-08-01

    Twenty-eight Capillariinae species have been recorded in rodents; 1 of these species was reported from a caviomorph rodent, Hydrochoeris hydrochaeris (capybara), and placed in the genus Echinocoleus by Moravec (1982). However, both original description and subsequent contributions of Echinocoleus hydrochoeri are poor and incomplete. In this paper, this species is redescribed, and a new geographical distribution is reported. The redescription is based on morphologic and morphometrical features; intestine ends in a cloaca beside ejaculatory duct, caudal bursa composed of 2 large ventrolateral lobes with a fleshy internal part and a membranous external part (they are not united dorsally with a membrane), 1 pair of caudal papillae, terminal part of cylindrical cirrus ornamented with thin and thick spines (and particular pattern distribution), sclerotized spicule in male, and vulvar appendage in female, and 3 bacillary bands (1 ventral and 2 lateral). Generic and specific analyses were performed to establish new standards for future studies on the systematic position of Capillariinae species. This study presents new morphological information and a new record of a capillariid species from Argentina.

  3. Penial morphology in three species of Brazilian tuco-tucos, Ctenomys torquatus, C. minutus, and C. flamarioni (Rodentia: Ctenomyidae).

    PubMed

    Rocha-Barbosa, O; Bernardo, J S L; Loguercio, M F C; Freitas, T R O; Santos-Mallet, J R; Bidau, C J

    2013-02-01

    The present study analyses the glans penis and baculum morphology of three Brazilian tuco-tucos, Ctenomys torquatus Lichtenstein, 1830, Ctenomys minutus Nehring, 1887 and Ctenomys flamarioni Travi, 1981, in order to identify possible variations and understand some more about this taxonomically complex group. We used fixed penis from 15 previously listed adult specimens. For a more detailed baculum analysis, the penis underwent dissection and diaphanisation, whereas to analyse the glans penis surface we used Scanning Electron Microscopy (SEM). Results showed striking differences in baculum morphology among the three species. While C. minutus have a particular V-shaped proximal baculum tip, C. flamarioni baculum is thin throughout the shaft with rounded proximal and distal tips. Ctenomys torquatus have a shorter and larger baculum, similar to what has previously been described for the species. Glans penis surface microstructure analyses also revealed inter-specific differences, with penial spines varying in shape, size and, especially density. Although C. torquatus has a relatively small penis, it has the largest penial spine density, which suggests a more complex penial ornamentation in this species.

  4. Chromosome synapsis and recombination in simple and complex chromosomal heterozygotes of tuco-tuco (Ctenomys talarum: Rodentia: Ctenomyidae).

    PubMed

    Basheva, Ekaterina A; Torgasheva, Anna A; Gomez Fernandez, Maria Jimena; Boston, Emma; Mirol, Patricia; Borodin, Pavel M

    2014-09-01

    The chromosomal speciation hypothesis suggests that irregularities in synapsis, recombination, and segregation in heterozygotes for chromosome rearrangements may restrict gene flow between karyotypically distinct populations and promote speciation. Ctenomys talarum is a South American subterranean rodent inhabiting the coastal regions of Argentina, whose populations polymorphic for Robertsonian and tandem translocations seem to have a very restricted gene flow. To test if chromosomal differences are involved in isolation among its populations, we examined chromosome pairing, recombination, and meiotic silencing of unsynapsed chromatin in male meiosis of simple and complex translocation heterozygotes using immunolocalization of the MLH1 marking mature recombination nodules and phosphorylated histone γH2A.X marking unrepaired double-strand breaks. We observed small asynaptic areas labeled by γH2A.X in pericentromeric regions of the chromosomes involved in the trivalents and quadrivalents. We also observed a decrease of recombination frequency and a distalization of the crossover distribution in the heterozygotes and metacentric homozygotes compared to acrocentric homozygotes. We suggest that the asynapsis of the pericentromeric regions are unlikely to induce germ cell death and decrease fertility of the heterozygotes; however, suppressed recombination in pericentromeric areas of the multivalents may reduce gene flow between chromosomally different populations of the Talas tuco-tuco.

  5. Evolutionary and biological implications of dental mesial drift in rodents: the case of the Ctenodactylidae (Rodentia, Mammalia).

    PubMed

    Gomes Rodrigues, Helder; Solé, Floréal; Charles, Cyril; Tafforeau, Paul; Vianey-Liaud, Monique; Viriot, Laurent

    2012-01-01

    Dental characters are importantly used for reconstructing the evolutionary history of mammals, because teeth represent the most abundant material available for the fossil species. However, the characteristics of dental renewal are presently poorly used, probably because dental formulae are frequently not properly established, whereas they could be of high interest for evolutionary and developmental issues. One of the oldest rodent families, the Ctenodactylidae, is intriguing in having longstanding disputed dental formulae. Here, we investigated 70 skulls among all extant ctenodactylid genera (Ctenodactylus, Felovia, Massoutiera and Pectinator) by using X-ray conventional and synchrotron microtomography in order to solve and discuss these dental issues. Our study clearly indicates that Massoutiera, Felovia and Ctenodactylus differ from Pectinator not only by a more derived dentition, but also by a more derived eruptive sequence. In addition to molars, their dentition only includes the fourth deciduous premolars, and no longer bears permanent premolars, conversely to Pectinator. Moreover, we found that these premolars are lost during adulthood, because of mesial drift of molars. Mesial drift is a striking mechanism involving migration of teeth allowed by both bone remodeling and dental resorption. This dental innovation is to date poorly known in rodents, since it is only the second report described. Interestingly, we noted that dental drift in rodents is always associated with high-crowned teeth favoring molar size enlargement. It can thus represent another adaptation to withstand high wear, inasmuch as these rodents inhabit desert environments where dust is abundant. A more accurate study of mesial drift in rodents would be very promising from evolutionary, biological and orthodontic points of view.

  6. Diversity of tuco-tucos (Ctenomys, Rodentia) in the Northeastern wetlands from Argentina: mitochondrial phylogeny and chromosomal evolution.

    PubMed

    Caraballo, Diego A; Abruzzese, Giselle A; Rossi, María Susana

    2012-06-01

    Tuco-tucos (small subterranean rodents of the genus Ctenomys) that inhabit sandy soils of the area under the influence of the second largest wetland of South America, in Northeastern Argentina (Corrientes province), are a complex of species and forms whose taxonomic status were not defined, nor are the evolutionary relationships among them. The tuco-tuco populations of this area exhibit one of the most ample grades of chromosomal variability within the genus. In order to analyze evolutionary relationships within the Corrientes group and its chromosomal variability, we completed the missing karyotypic information and performed a phylogenetic analysis. We obtained partial sequences of three mitochondrial markers: D-loop, cytochrome b and cytochrome oxidase I. The Corrientes group was monophyletic and split into three main clades that grouped related karyomorphs. The phylogeny suggested an ancestral condition of the karyomorph with diploid number (2n) 70 and fundamental number (FN) 84 that has evolved mainly via reductions of the FN although amplifications occurred in certain lineages. We discuss the relationship between patterns of chromosomal variability and species and groups boundaries. From the three main clades the one named iberá exhibited a remarkable karyotypic homogeneity, and could be considered as an independent and cohesive evolutionary lineage. On the contrary, the former recognized species C. dorbignyi is a polyphyletic lineage and hence its systematic classification should be reviewed.

  7. Germ cell differentiation and proliferation in the developing testis of the South American plains viscacha, Lagostomus maximus (Mammalia, Rodentia).

    PubMed

    Gonzalez, C R; Muscarsel Isla, M L; Fraunhoffer, N A; Leopardo, N P; Vitullo, A D

    2012-08-01

    Cell proliferation and cell death are essential processes in the physiology of the developing testis that strongly influence the normal adult spermatogenesis. We analysed in this study the morphometry, the expression of the proliferation cell nuclear antigen (PCNA), cell pluripotency marker OCT-4, germ cell marker VASA and apoptosis in the developing testes of Lagostomus maximus, a rodent in which female germ line develops through abolished apoptosis and unrestricted proliferation. Morphometry revealed an increment in the size of the seminiferous cords with increasing developmental age, arising from a significant increase of PCNA-positive germ cells and a stable proportion of PCNA-positive Sertoli cells. VASA showed a widespread cytoplasmic distribution in a great proportion of proliferating gonocytes that increased significantly at late development. In the somatic compartment, Leydig cells increased at mid-development, whereas peritubular cells showed a stable rate of proliferation. In contrast to other mammals, OCT-4 positive gonocytes increased throughout development reaching 90% of germ cells in late-developing testis, associated with a conspicuous increase in circulating FSH from mid- to late-gestation. TUNEL analysis was remarkable negative, and only a few positive cells were detected in the somatic compartment. These results show that the South American plains viscacha displays a distinctive pattern of testis development characterized by a sustained proliferation of germ cells throughout development, with no signs of apoptosis cell demise, in a peculiar endocrine in utero ambiance that seems to promote the increase of spermatogonial number as a primary direct effect of FSH.

  8. Litomosoides anguyai n. sp. (Nematoda: Onchocercidae) from Oxymycterus misionalis (Rodentia: Muridae) in the rain forest of Misiones, Argentina.

    PubMed

    Notarnicola, Juliana; Bain, Odile; Navone, Graciela

    2002-06-01

    A new species of Litomosoides is described from sigmodontine murids occurring in the rain forests of Misiones, Argentina. Litomosoides anguyai n. sp., a parasite of the abdominal cavity of Oxymycterus misionalis, belongs to the sigmodontis group and is closely related to L. legerae and L. oxymycteri. The new species is differentiated by the salient amphids, an asymmetrical annular thickening of the buccal capsule, by the arrangement of the head and tail papillae, and the shape and size of the microfilaria.

  9. A new form of the mole vole Ellobius tancrei Blasius, 1884 (Mammalia, Rodentia) with the lowest chromosome number

    PubMed Central

    Bakloushinskaya, Irina; Romanenko, Svetlana A.; Serdukova, Natalia A.; Graphodatsky, Alexander S.; Lyapunova, Elena A.

    2013-01-01

    Abstract The subterranean mole vole, Ellobius tancrei, with aspecific variability in autosomes (2n = 31–54) and unusual sex chromosomes (XX in males and females), represents an amazing model for studying the role of chromosome changes in speciation. New materials from the upper reaches of the Surkhob River in the Pamiro-Alay mountains resulted in the discovery of a new form with 2n = 30. The application of Zoo-FISH and G-banding methods allowed the detection of 13 pairs of autosomes as Robertsonian metacentrics originated after fusions of acrocentrics of an assumed ancestral karyotype of Ellobius tancrei with 2n = 54. The sex chromosomes (XX, in both sexes) and one pair of acrocentric autosomes are the only acrocentrics in this karyotype, and the set with 2n = 30 possesses the lowest possible chromosome number among populations of Ellobius tancrei. PMID:24260698

  10. Molecular genetic typing of three forms of wood and field mice belonging to a transpalearctic genus (Apodemus, Muridae, Rodentia)

    SciTech Connect

    Chelomina, G.N.; Lyapunova, E.A.; Vorontsov, N.N.

    1995-06-01

    The genomes of three species of wood mouse (Apodemus fulvipectus and A. ponticus from the Caucasus and A. argenteus from Japan) were compared by means of restriction analysis of nuclear DNA. The species are differentiated from each other and from previously studied species. Each species has its species-specific features. Within the genus Apodemus, A. ponticus is most closely related to the European species A. sylvaticus and A. flavicollis. A. fulvipectus has a peculiar type of restriction with EcoR I (specific for dispersed repeats) and Hind III (specific for satDNA). The genome of this species contains three families of EcoR I repeats previously found in various species (European and Asian) of wood mouse and Hind III components characteristic of both wood and field mice. A. argenteus differs from all other forms of Apodemus, the genome of which contains the 375-bp Hind III satellite, by the presence of an EcoR I satDNA fraction consisting of 240-bp repeating units. 22 refs., 2 figs.

  11. Pterygodermatites (Mesopectines) quentini (Nematoda, Rictulariidae), a parasite of Praomys rostratus (Rodentia, Muridae) in Mali: scanning electron and light microscopy.

    PubMed

    Diouf, Malick; Quilichini, Yann; Granjon, Laurent; Bâ, Cheikh Tidiane; Marchand, Bernard

    2013-01-01

    Pterygodermatites (Mesopectines) quentini n. sp. (Nematoda, Rictulariidae) is described from the murine host Praomys rostratus in the south of the Republic of Mali. It differs from other species of the subgenus by the morphology of the head, which bears four simple cephalic papillae and a nearly axial oral opening, the number of caudal papillae, the number of precloacal cuticular formations, unequal spicules and the ratio of spicule lengths/body length. The use of scanning electron microscopy in combination with conventional light microscopy enabled us to give a detailed description of the morphological characters of this new species.

  12. Laoxyuris laonasti n. gen., n. sp. (Nematoda: Syphaciinae) parasite of Laonastes aenigmamus (Rodentia: Diatomyidae): morphology, biology, taxonomy, phylogeny.

    PubMed

    Hugot, Jean Pierre; Feliu, Carlos; Douangboupha, Bounneuang; Ribas, Alexis

    2013-06-01

    A new Oxyurid genus and species are described in a rodent recently discovered in Lao PDR: Laonastes aenigmamus which happens to be the single survivor of the Diatomyidae, a family considered to be extinct since the Miocene. The morphological characters of the new parasite species allow classifying it within the Syphaciinae Railliet, 1916, a subfamily whose members are exclusively parasites of Lagomorpha and Rodents. Male Syphaciinae have developed several types of ventral cuticular ornamentation used to firmly grip the female during mating. The ornamental characters observed in the new species include a finger like appendix, which, until now, has not been described in the subfamily. The originality of this apparatus justifies the creation of a new genus and a new species for the pinworm parasite of Laonastes. Using morphological characters, the new species is analyzed phylogenetically to describe its affinities with representatives of the main groups distinguished within the Syphaciinae. The phylogenetic study produces a cladogram similar to the phylogeny recently proposed for the hosts of the subfamily and in agreement with a close association of the Diatomyidae with the Ctenodactylidae. Such a phenomenon of cophylogeny is interpreted as the result of the existence of a strict specificity between the Syphaciinae and their respective hosts, due to the very close adaptation of their life cycle with the behaviors of their hosts. In Lagomorpha and Rodents, caecotrophy and grooming activities allow a direct transmission of the parasite eggs and favor successive self-infestations, increasing the chances for the parasite to maintain itself in the same host species but decreasing the probability of host switching. The resulting high host specificity allowed the Syphaciinae to out-compete other pinworms and maintain themselves in their specific host over millions of years.

  13. Into Tibet: An Early Pliocene Dispersal of Fossil Zokor (Rodentia: Spalacidae) from Mongolian Plateau to the Hinterland of Tibetan Plateau.

    PubMed

    Li, Qiang; Wang, Xiaoming

    2015-01-01

    This paper reports the fossil zokors (Myospalacinae) collected from the lower Pliocene (~4.4 Ma) of Zanda Basin, southwestern Tibet, which is the first record in the hinterland of Tibetan Plateau within the Himalayan Range. Materials include 29 isolated molars belonging to Prosiphneus eriksoni (Schlosser, 1924) by having characters including large size, highly fused roots, upper molars of orthomegodont type, m1 anterior cap small and centrally located, and first pair of m1 reentrants on opposing sides, high crowns, and high value of dentine tract parameters. Based on the cladistics analysis, all seven species of Prosiphneus and P. eriksoni of Zanda form a monophyletic clade. P. eriksoni from Zanda, on the other hand, is nearly the terminal taxon of this clade. The appearance of P. eriksoni in Zanda represents a significant dispersal in the early Pliocene from its center of origin in north China and Mongolian Plateau, possibly via the Hol Xil-Qiangtang hinterland in northern Tibet. The fast evolving zokors are highly adapted to open terrains at a time when regional climates had become increasingly drier in the desert zones north of Tibetan Plateau during the late Miocene to Pliocene. The occurrence of this zokor in Tibet thus suggests a rather open steppe environment. Based on fossils of large mammals, we have formulated an "out of Tibet" hypothesis that suggests earlier and more primitive large mammals from the Pliocene of Tibet giving rise to the Ice Age megafauna. However, fossil records for large mammals are still too poor to evaluate whether they have evolved from lineages endemic to the Tibetan Plateau or were immigrants from outside. The superior record of small mammals is in a better position to address this question. With relatively dense age intervals and numerous localities in much of northern Asia, fossil zokors provide the first example of an "into Tibet" scenario--earlier and more primitive taxa originated from outside of the Tibetan Plateau and the later the lineage became extinct in southwestern Tibet.

  14. Masticatory muscle architecture in the Laotian rock rat Laonastes aenigmamus (Mammalia, Rodentia): new insights into the evolution of hystricognathy

    PubMed Central

    Hautier, Lionel; Saksiri, Soonchan

    2009-01-01

    We present the first descriptive comparison of the skull, mandible and jaw muscles of the recently recovered Laotian rock rat Laonastes aenigmamus. The gross anatomy of five specimens captured in Laos and internal architecture of the jaw musculature were studied using dissections. The following muscles are described: temporal, masseter, pterygoids, digastric, mylohyoid, geniohyoid and transverse mandibular. The description of the masticatory apparatus of L. aenigmamus offers a rare opportunity to assess the order of establishment of the morphological characters during the evolution of Ctenohystrica. Striking convergences have occurred during the evolution of Diatomyidae and L. aenigmamus presents a unique combination of myological features that corresponds to a mixture of sciurognathous and hystricognathous characters. If L. aenigmamus is a sciurognathous rodent, we have to assume that it independently acquired a pars reflexa of the superficial masseter. We show for the first time that the development of this pars reflexa has occurred several times during the evolution of Ctenohystrica and can no longer be considered a synapomorphic feature of ‘Hystricognathi’. These results bring new insights into the evolution of hystricognathy and have profound implications for the interpretation of the fossil record of early hystricognath rodents. PMID:19694873

  15. A new host of Trypanosoma cruzi from Jujuy, Argentina: Octodontomys gliroides (Gervais & D'Orbigny, 1844) (Rodentia, Octodontidae).

    PubMed

    Schweigmann, N J; Alberti, A; Pietrokovsky, S; Conti, O; Riarte, A; Montoya, S; Wisnivesky-Colli, C

    1992-01-01

    To identify wild hosts of Trypanosoma cruzi, surveys were conducted in the subandean valleys of Jujuy Province, Argentina, between June 1986 and March 1987. Seventy two mammals from 13 different species were examined by xenodiagnosis. Fifty two of them were mostly rodents trapped at the localities of Maimará, León and Tilcara, and the remainder had been kept in captivity at the Estación Biológica Experimental, in Jujuy. Trypanosoma cruzi infection was detected only in 2 Octodontomys gliroides (2 pos./8 exam. 25%) from all 72 examined mammals. Isolates were called Octodontomys Argentina 1 and 2 (OA1 and OA2). Both infected animals were caught at the archaelogical ruin of Pucará, at Tilcara. Repeated searches for triatomines in the ruin itself and in neighbour houses rendered negative results. Groups of mice inoculated with either OA1 or OA2 isolates became infected between 7 (OA1) to 12 days (OA2) postinoculation PI. Parasitemia peaks were observed between day 12th-14th PI. Scarce amastigote nests were found in myocardium and skeletal muscle. Mortality was observed only for mice inoculated with OA1. Isoenzyme patterns of OA1 and OA2 were identical to one found in dogs and slightly different from that of human parasites in Argentina. Bones from Octodontomys sp., were recently found in a cave, dated 10200-8600 BC, in Pumamarca, near Tilcara, Jujuy. There are evidences that O. gliroides cohabited with man in ancient times and was associated to the domestic cycle of T. cruzi transmission, playing a role like that of domestic caves in Bolivia.

  16. Comparative glycopattern analysis of mucins in the Brunner's glands of the guinea-pig and the house mouse (Rodentia).

    PubMed

    Scillitani, Giovanni; Mentino, Donatella

    2015-09-01

    The mucins secreted by the Brunner's glands and the duodenal goblet cells of the Guinea-pig and the house mouse were compared by conventional and FITC-conjugated lectin histochemistry. Methylation/saponification and sialidase digestion were performed prior to lectin binding to detect the residues subterminal to sulfated groups and sialic acid, respectively. In the Guinea-pig the Brunner's glands produce class-III stable sulfosialomucins. Sialic acid is mostly 2,6-linked to galactose or to N-acetylgalactosamine and is in part O-acetylated in C7, C8, and C9. Sulfated groups are probably linked to sialic acid and N-acetylgalactosamine. Terminal residuals of N-acetylglucosamine, galactose, N-acetylgalactosamine and fucose linked in α1,2, α1,3, and α1,4 are also present. Duodenal goblet cells of the Guinea-pig present a lower number of residuals in respect to the Brunner's glandular ones, with sialic acid and N-acetylgalactosamine subterminal to sulfated groups. In the house mouse the Brunner's glands produce class-III stable neutral mucins, binding to same lectins as in the Guinea-pig except for those specific to sialic acid. A diversity of fucosylated residuals higher than in the Guinea-pig is observed. The mouse duodenal goblet cells lack stable class-III mucins, have little sialic acid and present a lower number of residuals in respect to the correspondent Brunner's glands. Regulation of the acidic intestinal microenvironment, prevention of pathologies and hosting of microflora can explain the observed results and the differences observed between the two rodents.

  17. Comparative Chromosome Painting in Six Species of Oligoryzomys (Rodentia, Sigmodontinae) and the Karyotype Evolution of the Genus

    PubMed Central

    Di-Nizo, Camilla Bruno; Ventura, Karen; Ferguson-Smith, Malcolm Andrew; O’Brien, Patricia Caroline Mary; Yonenaga-Yassuda, Yatiyo; Silva, Maria José de J.

    2015-01-01

    Oligoryzomys belongs to the tribe Oryzomyini, and contains about 22 species. Diploid numbers range from 2n = 44 in Oligoryzomys sp. 2 to 2n = 72 in O. utiaritensis and phylogenetic relationships are not well defined. The high morphological convergence leads to misidentification of taxonomic entities and the species are often identified by chromosomal characters. Until now, the genus has been studied only by classical cytogenetic approaches. To understand the chromosomal evolution of Oligoryzomys, we developed chromosome probes from a female of Oligoryzomys moojeni (OMO) with 2n = 70 and hybridized to other five Oligoryzomys species. The probes painted 31 segments on O. fornesi (OFO) with 2n = 62; 32 segments on O. microtis (OMI), 2n = 64; 33 segments on O. nigripes (ONI), 2n = 62 and on O. rupestris (ORU), 2n = 46; and 34 on Oligoryzomys sp. 2 (OSP), 2n = 44. OMO probes 4 and 5 showed a syntenic association in O. fornesi, O. microtis and O. nigripes and were also presented in the same pair, although disrupted, in O. rupestris and Oligoryzomys sp. 2. Concerning O. rupestris and Oligoryzomys sp. 2, species with the lowest diploid numbers of the genus, a total of 8 probes hybridized to 11 segments on the largest pair of ORU 1 and 9 probes hybridized to 12 segments on OSP 1. Also, OMO 6 painted three segments in ORU, corresponding to the proximal segment of ORU 2q, and the whole of ORU 19 and 20. In OSP, the segment corresponding to ORU 20 was homologous to OSP 1p. OMO X showed signals of hybridization in both X and Y chromosomes. Extensive chromosomal rearrangements, that could not be detected by classical cytogenetic techniques, such as pericentric inversions or repositioning of centromeres, Robertsonian rearrangements and tandem fusions/fissions, as well as gain/activation or loss/inactivation of centromeres and telomeric sequences have driven the huge genome reshuffling in these closely related species. PMID:25658766

  18. Brain structure volumes in the mole rat, Spalax ehrenbergi (Spalacidae, Rodentia) in comparison to the rat and subterrestrial insectivores.

    PubMed

    Frahm, H D; Rehkämper, G; Nevo, E

    1997-01-01

    Natural blindness and a subterranean, digging mode of life demand peculiar adaptations of the central nervous system in the mole rat Spalax ehrenbergi, which are the focus of this quantitative investigation. Volumes of 25 brain structures in Spalax were evaluated allometrically, using the least encephalized mammalian species, the Madagassian hedgehog-like tenrecs (Tenrecinae) as a reference base, and their sizes compared with those of the rat (as a more generalized representative of rodents) and of some subterranean Insectivora. The allometric approach reveals that Spalax has a larger brain than tenrecs and the rat. Within the brain, the neocortex and diencephalon are well developed, an observation also made in other mammalian species with a relatively high encephalization. An unique feature in Spalax is the enlargement of motor structures of the brain, such as the cerebellum (and cerebellar nuclei), and the striatum. Most conspicuous is the large size of the nucleus motorius nervi trigemini, reflecting the importance of masticatory muscles for the special digging technique, which demand an intense use of the teeth for loosening the soil.

  19. A new allopatric lineage of the rodent Deltamys (Rodentia: Sigmodontinae) and the chromosomal evolution in Deltamys kempi and Deltamys sp.

    PubMed

    Ventura, K; Fagundes, V; D'Elía, G; Christoff, A U; Yonenaga-Yassuda, Y

    2011-01-01

    Deltamys Thomas 1917 is a poorly studied and rarely collected taxon of Akodontini (Sigmodontinae). The single described species, Deltamys kempi (DKE), has a basic karyotype with a diploid number of 2n = 37 in males and 2n = 38 in females, a fundamental number FN = 38 for both sexes, and an X(1)X(1)X(2)X(2)/X(1)X(2)Y sex determination system. Herein, a new allopatric form, Deltamys sp. (DSP), is reported, based on specimens from southern Brazil, with 2n = 40, FN = 40 and XX/XY sex chromosomes. We describe the karyotype and mechanism of chromosomal differentiation between both Deltamys complements. Phylogenetic analyses, based on the complete sequence (1,140 bp) of the mitochondrial cytochrome b gene, grouped Deltamys sp. as sister species to D. kempi, with up to 12% genetic divergence between them. The GTG-banding patterns show complete autosomal correspondence between D. kempi and Deltamys sp. and identify a tandem rearrangement involving DSP7, DSP19 and DKE4 that is responsible for the differences in 2n and FN. Chromosome painting with Akodon paranaensis chromosome 21 (a small metacentric akodont marker) paint revealed total homology with the smallest acrocentric Deltamys sp. chromosome, DSP19. This suggests the occurrence of a pericentric inversion or centromeric shift when compared to other akodontines, with a posterior tandem rearrangement giving rise to DKE4. In DKE, large blocks of pericentromeric constitutive heterochromatin are present on the autosomes and the X, and the Y/autosome has an entirely heterochromatic short arm. In DSP, small heterochromatic blocks are observed on autosomes and X, and the Y is a very small, mostly heterochromatic acrocentric. The cytogenetic analyses suggest that the Deltamys sp. karyotype is ancestral, with the derived condition resulting from a tandem fusion (DSP7 + DSP19) and the Y/autosome translocation giving rise to the multiple sex chromosome system. The autosomal rearrangements, the differences in CBG-banding patterns and Ag-NOR localization, as well as the presence of X(1)X(1)X(2)X(2)/X(1)X(2)Y and XX/XY sex determination mechanisms, possibly acting as a reproductive barrier, and the phylogenetic position within the Deltamys genus, with high genetic divergence, call for a taxonomic review of the genus.

  20. Graphidioides subterraneus n. sp. (Nematoda: Trichostrongyloidea) from the South American subterranean rodent Ctenomys talarum Thomas, 1898 (Rodentia: Octodontidae).

    PubMed

    Rossin, M A; Timi, J T; Malizia, A I

    2005-06-01

    A new nematode species, Graphidioides subterraneus n. sp., found in the stomach of C. talarum from Argentina is described. The new species more closely resembles G. mazzai Lent & Freitas, 1935, parasite of Galea leucoblephara from Argentina, and G. kravetzi Sutton & Durette-Desset, 1995, parasite of Holochilus brasiliensis from Uruguay. It can be distinguished by shorter spicules, by the shape of the gubernaculum, by shorter uterine branches, and by a different number of ridges of the synlophe all along the body.

  1. Ecological implications on the aggregation of Amblyomma fuscum (Acari: Ixodidae) on Thrichomys laurentius (Rodentia: Echimyidae), in northeastern Brazil.

    PubMed

    Aléssio, Filipe Martins; Dantas-Torres, Filipe; Siqueira, Daniel Barreto; Lizée, Marie-Hélène; Marvulo, Maria Fernanda Vianna; Martins, Thiago Fernandes; Labruna, Marcelo Bahia; Silva, Jean Carlos Ramos; Mauffrey, Jean-François

    2012-05-01

    We investigated the Amblyomma fuscum load on a pullulating wild rodent population and the environmental and biological factors influencing the tick load on the hosts. One hundred and three individuals of Thrichomys laurentius were caught in an Atlantic forest fragment in northeastern Brazil, as part of a longitudinal survey on ticks infesting non-volant small mammals. Ticks (n = 342) were found on 45 individuals and the overall mean intensity of infestation was 7.6 ticks per infested rodent. Ticks were highly aggregated in the host population and the negative binomial distribution model provides a statistically satisfactory fit. The aggregated distribution was influenced by sex and age of the host. The microhabitat preference by T. laurentius probably increases contact opportunities between hosts and aggregated infesting stages of the ticks and represents important clues about the habitat suitability for A. fuscum.

  2. On the Origin and Evolution of the Extant System of B Chromosomes in Oryzomyini Radiation (Rodentia, Sigmodontinae).

    PubMed

    Ventura, Karen; O'Brien, Patricia Caroline Mary; do Nascimento Moreira, Camila; Yonenaga-Yassuda, Yatiyo; Ferguson-Smith, Malcolm Andrew

    2015-01-01

    Heterogeneous supernumerary chromosomes (Bs) are recognized in the oryzomyines Holochilus brasiliensis, Nectomys rattus, N. squamipes, Oligoryzomys flavescens and Sooretamys angouya, representing about 10% of all known B-containing rodent species. They provide an outstanding model for understanding the origin, evolution and diversity of Bs in a phylogenetic context. Therefore, whole chromosome-specific probes were generated from flow-sorted Holochilus brasiliensis (HBR) autosomes 11 and 25+26 and chromosomes X, Y and Bs. Hybridizations were performed on male metaphases of 15 Oryzomyini species of which 3 are B-containing species. The results reveal that among the species sampled, 12 of them, belonging to a monophyletic Oryzomiyini subclade, are positive for an anonymous Oryzomyini shared heterochromatic region (OSHR) on both sex chromosomes. The OSHR is also present on Bs of Holochilus brasiliensis, Nectomys rattus and N. squamipes but not on Bs of O. flavescens and S. angouya. Two distinct additional OSHR/autosome associations are observed on S. angouya. The three species that are OSHR negative belong to an outgroup. Molecular dating suggests that the OSHR originated between 7.8 and 3 Mya on ancestral sex chromosomes. A tentative explanation for the OSHR-positive nature of B regions in three species could be that transposable elements (TEs) from this specific sex chromosome region may have invaded existing B chromosomes. The presence of the OSHR on entire Xp and Yp adjacent to interstitial telomeric sequences at pericentromeric positions, as observed in Drymoreomys albimaculatus, show a similar organization as on B chromosomes in Nectomys squamipes. The diversity of the Oryzomyini Bs in number, size, morphology and genetic content may be explained by the independent origin of B chromosomes in different subgroups of species, with Bs in Holochilus brasiliensis, Nectomys squamipes and N. rattus sharing the OSHR with sex chromosomes, and those in Oligoryzomys flavescens and Sooretamys angouya lacking OSHR in Bs. The species-specific pattern of Bs is probably a consequence of their independent evolutionary origin.

  3. On the Origin and Evolution of the Extant System of B Chromosomes in Oryzomyini Radiation (Rodentia, Sigmodontinae)

    PubMed Central

    Ventura, Karen; O’Brien, Patricia Caroline Mary; do Nascimento Moreira, Camila; Yonenaga-Yassuda, Yatiyo; Ferguson-Smith, Malcolm Andrew

    2015-01-01

    Heterogeneous supernumerary chromosomes (Bs) are recognized in the oryzomyines Holochilus brasiliensis, Nectomys rattus, N. squamipes, Oligoryzomys flavescens and Sooretamys angouya, representing about 10% of all known B-containing rodent species. They provide an outstanding model for understanding the origin, evolution and diversity of Bs in a phylogenetic context. Therefore, whole chromosome-specific probes were generated from flow-sorted Holochilus brasiliensis (HBR) autosomes 11 and 25+26 and chromosomes X, Y and Bs. Hybridizations were performed on male metaphases of 15 Oryzomyini species of which 3 are B-containing species. The results reveal that among the species sampled, 12 of them, belonging to a monophyletic Oryzomiyini subclade, are positive for an anonymous Oryzomyini shared heterochromatic region (OSHR) on both sex chromosomes. The OSHR is also present on Bs of Holochilus brasiliensis, Nectomys rattus and N. squamipes but not on Bs of O. flavescens and S. angouya. Two distinct additional OSHR/autosome associations are observed on S. angouya. The three species that are OSHR negative belong to an outgroup. Molecular dating suggests that the OSHR originated between 7.8 and 3 Mya on ancestral sex chromosomes. A tentative explanation for the OSHR-positive nature of B regions in three species could be that transposable elements (TEs) from this specific sex chromosome region may have invaded existing B chromosomes. The presence of the OSHR on entire Xp and Yp adjacent to interstitial telomeric sequences at pericentromeric positions, as observed in Drymoreomys albimaculatus, show a similar organization as on B chromosomes in Nectomys squamipes. The diversity of the Oryzomyini Bs in number, size, morphology and genetic content may be explained by the independent origin of B chromosomes in different subgroups of species, with Bs in Holochilus brasiliensis, Nectomys squamipes and N. rattus sharing the OSHR with sex chromosomes, and those in Oligoryzomys flavescens and Sooretamys angouya lacking OSHR in Bs. The species-specific pattern of Bs is probably a consequence of their independent evolutionary origin. PMID:26305702

  4. Comparison of climate space and phylogeny of Marmota (Mammalia: Rodentia) indicates a connection between evolutionary history and climate preference

    PubMed Central

    Davis, Edward Byrd

    2005-01-01

    Palaeobiologists have investigated the evolutionary responses of extinct organisms to climate change, and have also used extinct organisms to reconstruct palaeoclimates. There is evidence of a disconnection between climate change and evolution that suggests that organisms may not be accurate palaeoclimate indicators. Here, marmots (Marmota sp.) are used as a case study to examine whether similarity of climate preferences is correlated with evolutionary relatedness of species. This study tests for a relationship between phylogenetic distance and `climate distance' of species within a clade. There should be a significant congruence between maximum likelihood distance and standardized Euclidian distance between climates if daughter species tend to stay in environments similar to parent species. Marmots make a good test case because there are many extant species, their phylogenies are well established and individual survival is linked to climatic factors. A Mantel test indicates a significant correlation between climate and phylogenetic distance matrices, but this relationship explains only a small fraction of the variance (regression R2=0.114). These results suggest that (i) closely related species of marmots tend to stay in similar environments; (ii) marmots may be more susceptible than many mammals to global climate change; and (iii) because of the considerable noise in this system, the correlation cannot be used for detailed palaeoclimate reconstruction. PMID:15799948

  5. New data on occurrence of Demodex flagellurus (Acari, Demodecidae) - rarely recorded parasite from the house mouse Mus musculus (Rodentia, Muridae).

    PubMed

    Izdebska, Joanna N; Rolbiecki, Leszek

    2015-01-01

    Demodex flagellurus Bukva, 1985 is one of two known demodecid mites of the house mouse Mus musculus Linnaeus, 1758, in which it is observed in genital area. Skin fragments of 30 house mice from various regions of Poland (residential buildings in Gdynia and Gdańsk, rural region in Wielkopolska-Kujawska Lowland) were examined. The mites were noted in 25.0% of the mice, with mean intensity of 48.0 and intensity range of 2-103. D. flagellurus demonstrated the differentiated occurrence in host populations.

  6. Chronology and causes of the extinction of the Lava Mouse, Malpaisomys insularis (Rodentia: Muridae) from the Canary Islands

    NASA Astrophysics Data System (ADS)

    Rando, Juan Carlos; Alcover, Josep Antoni; Navarro, Juan Francisco; García-Talavera, Francisco; Hutterer, Rainer; Michaux, Jacques

    2008-09-01

    Understanding late Holocene extinctions on islands requires accurate chronologies for all relevant events, including multiple colonisations by humans and the introduction of alien species. The most widely held hypothesis on the causes of Holocene island vertebrate extinctions incorporates human impacts, although climatic-related hypotheses cannot be excluded. Both hypotheses have been suggested to account for the extinction of the endemic Lava Mouse, Malpaisomys insularis from the Canary Islands. Here we present the first accelerator mass spectrometer (AMS) 14C ages from collagen of M. insularis bones from ancient owl pellets collected at Fuerteventura (Canary Islands, eastern Atlantic Ocean). These new dates contribute to an understanding of the extinction of this species. We are able to exclude climatic causes, predation by invasive species, and competition with the house mouse, Mus musculus. The arrival of Europeans in the Canary Islands correlates with the extinction of Malpaisomys. The introduction of rats, Rattus spp., together with their parasites and diseases, emerges as the most reasonable hypothesis explaining the extinction of M. insularis.

  7. Microcavia australis (Caviidae, Rodentia), a new highly competent host of Trypanosoma cruzi I in rural communities of northwestern Argentina.

    PubMed

    Cecere, M Carla; Cardinal, Marta V; Arrabal, Juan P; Moreno, Claudio; Gürtler, Ricardo E

    2015-02-01

    Rodents are well-known hosts of Trypanosoma cruzi but little is known on the role of some caviomorph rodents. We assessed the occurrence and prevalence of T. cruzi infection in Microcavia australis ("southern mountain, desert or small cavy") and its infectiousness to the vector Triatoma infestans in four rural communities of Tafí del Valle department, northwestern Argentina. Parasite detection was performed by xenodiagnosis and polymerase chain reaction amplification of the hyper-variable region of kinetoplast DNA minicircles of T. cruzi (kDNA-PCR) from blood samples. A total of 51 cavies was captured in traps set up along cavy paths in peridomestic dry-shrub fences located between 25 and 85 m from the nearest domicile. We document the first record of M. australis naturally infected by T. cruzi. Cavies presented a very high prevalence of infection (46.3%; 95% confidence interval, CI=33.0-59.6%). Only one (4%) of 23 cavies negative by xenodiagnosis was found infected by kDNA-PCR. TcI was the only discrete typing unit identified in 12 cavies with a positive xenodiagnosis. The infectiousness to T. infestans of cavies positive by xenodiagnosis or kDNA-PCR was very high (mean, 55.8%; CI=48.4-63.1%) and exceeded 80% in 44% of the hosts. Cavies are highly-competent hosts of T. cruzi in peridomestic habitats near human dwellings in rural communities of Tucumán province in northwestern Argentina.

  8. Genetic pool information reflects highly suitable areas: the case of two parapatric endangered species of Tuco-tucos (Rodentia: Ctenomiydae).

    PubMed

    Galiano, Daniel; Bernardo-Silva, Jorge; Freitas, Thales R O de

    2014-01-01

    Conservation of small mammals requires knowledge of the genetically and ecologically meaningful spatial scales at which species respond to habitat modifications. Conservation strategies can be improved through the use of ecological niche models and genetic data to classify areas of high environmental suitability. In this study, we applied a Maxent model integrated with genetic information (nucleotide diversity, haplotype diversity and Fu's Fs neutrality tests) to evaluate potential genetic pool populations with highly suitable areas for two parapatric endangered species of tuco-tucos (Ctenomys minutus and C. lami). Our results demonstrated that both species were largely influenced by vegetation and soil variables at a landscape scale and inhabit a highly specific niche. Ctenomys minutus was also influenced by the variable altitude; the species was associated with low altitudes (sea level). Our model of genetic data associated with environmental suitability indicate that the genetic pool data were associated with highly suitable areas for C. minutus. This pattern was not evident for C. lami, but this outcome could be a consequence of the restricted range of the species. The preservation of species requires not only detailed knowledge of their natural history and genetic structure but also information on the availability of suitable areas where species can survive, and such knowledge can aid significantly in conservation planning. This finding reinforces the use of these two techniques for planning conservation actions.

  9. On cognitive ecology and the environmental factors that promote Alzheimer disease: lessons from Octodon degus (Rodentia: Octodontidae).

    PubMed

    Rivera, Daniela S; Inestrosa, Nibaldo C; Bozinovic, Francisco

    2016-02-20

    Cognitive ecologist posits that the more efficiently an animal uses information from the biotic and abiotic environment, the more adaptive are its cognitive abilities. Nevertheless, this approach does not test for natural neurodegenerative processes under field or experimental conditions, which may recover animals information processing and decision making and may explain, mechanistically, maladaptive behaviors. Here, we call for integrative approaches to explain the relationship between ultimate and proximate mechanisms behind social behavior. We highlight the importance of using the endemic caviomorph rodent Octodon degus as a valuable natural model for mechanistic studies of social behavior and to explain how physical environments can shape social experiences that might influence impaired cognitive abilities and the onset and progression of neurodegenerative disorders such as Alzheimer disease. We consequently suggest neuroecological approaches to examine how key elements of the environment may affect neural and cognitive mechanisms associated with learning, memory processes and brain structures involved in social behavior. We propose the following three core objectives of a program comprising interdisciplinary research in O. degus, namely: (1) to determine whether diet types provided after weaning can lead to cognitive impairment associated with spatial memory, learning and predisposing to develop Alzheimer disease in younger ages; (2) to examine if early life social experience has long term effects on behavior and cognitive responses and risk for development Alzheimer disease in later life and (3) To determine if an increase of social interactions in adult degu reared in different degree of social stressful conditions alter their behavior and cognitive responses.

  10. Comparative chromosome painting in six species of Oligoryzomys (Rodentia, Sigmodontinae) and the karyotype evolution of the genus.

    PubMed

    Di-Nizo, Camilla Bruno; Ventura, Karen; Ferguson-Smith, Malcolm Andrew; O'Brien, Patricia Caroline Mary; Yonenaga-Yassuda, Yatiyo; Silva, Maria José de J

    2015-01-01

    Oligoryzomys belongs to the tribe Oryzomyini, and contains about 22 species. Diploid numbers range from 2n = 44 in Oligoryzomys sp. 2 to 2n = 72 in O. utiaritensis and phylogenetic relationships are not well defined. The high morphological convergence leads to misidentification of taxonomic entities and the species are often identified by chromosomal characters. Until now, the genus has been studied only by classical cytogenetic approaches. To understand the chromosomal evolution of Oligoryzomys, we developed chromosome probes from a female of Oligoryzomys moojeni (OMO) with 2n = 70 and hybridized to other five Oligoryzomys species. The probes painted 31 segments on O. fornesi (OFO) with 2n = 62; 32 segments on O. microtis (OMI), 2n = 64; 33 segments on O. nigripes (ONI), 2n = 62 and on O. rupestris (ORU), 2n = 46; and 34 on Oligoryzomys sp. 2 (OSP), 2n = 44. OMO probes 4 and 5 showed a syntenic association in O. fornesi, O. microtis and O. nigripes and were also presented in the same pair, although disrupted, in O. rupestris and Oligoryzomys sp. 2. Concerning O. rupestris and Oligoryzomys sp. 2, species with the lowest diploid numbers of the genus, a total of 8 probes hybridized to 11 segments on the largest pair of ORU 1 and 9 probes hybridized to 12 segments on OSP 1. Also, OMO 6 painted three segments in ORU, corresponding to the proximal segment of ORU 2q, and the whole of ORU 19 and 20. In OSP, the segment corresponding to ORU 20 was homologous to OSP 1p. OMO X showed signals of hybridization in both X and Y chromosomes. Extensive chromosomal rearrangements, that could not be detected by classical cytogenetic techniques, such as pericentric inversions or repositioning of centromeres, Robertsonian rearrangements and tandem fusions/fissions, as well as gain/activation or loss/inactivation of centromeres and telomeric sequences have driven the huge genome reshuffling in these closely related species.

  11. Redescription of Gyropus parvus (Ewing, 1924) (Insecta: Phthiraptera: Amblycera: Gyropidae) from tucos-tucos (Rodentia: Ctenomyidae: Ctenomys ) in Patagonia, Argentina.

    PubMed

    Martino, N S; Romero, M D; Castro, D C

    2010-02-01

    A detailed redescription of Gyropus parvus (Insecta: Phthiraptera: Amblycera: Gyropidae) is given based on specimens collected from the type host, Ctenomys colburni Allen 1903 , and the type locality, Estancia Huanuluán, Provincia de Rio Negro, Argentina. We expand and provide new chaetotaxy. New scanning electron microscopy images showing microstructural details of adults and eggs of G. parvus obtained from topotype specimens are included. Sexual dimorphism was mainly shown by differences in body size and abdominal chaetotaxy, with females being 17.5% larger than males and with more setae in each cluster. Significant differences between males and females were also observed in sternal plate measurements. Features described here show homogeneity within type host population. This information contributes to our knowledge of intra- and inter-specific variability for parasite populations. Our investigation constitutes the first collection of G. parvus from the type host and locality since it was described.

  12. Chemical signals involved in spacing behavior of breeding female bank voles (Clethrionomys glareolus Schreber 1780, Microtidae, Rodentia).

    PubMed

    Rozenfeld, F M; Denoël, A

    1994-03-01

    In order to study the mechanism involved in the seasonal territoriality of breeding bank voles, the social behavior and scent marking of paired females were observed throughout a reproductive cycle. Initially unfamiliar females were kept in large laboratory pens provided with individual burrows. After a brief period of hostility, females behaved in a friendly manner towards each other, sharing the same nest even in the presence of a male and until the middle of pregnancy. They scarcely marked with urine. Continuous olfactory assessment appeared to play an important role in maintaining the friendly interactions. In late pregnant and lactating females, on the contrary, the odor of a familiar female triggered aggressiveness and scent marking with urine and probably with flank glands. These reactions may be interpreted as spacing behavior. Moreover, the interaction between females may inhibit reproduction in one of them. These results are discussed in relation with the available ecological data.

  13. The comparative anatomy of the abdominal gastrointestinal tract of six species of African mole-rats (Rodentia, Bathyergidae).

    PubMed

    Kotzé, Sanet H; Van Der Merwe, Elizabeth L; Bennett, Nigel C; O'Riain, M Justin

    2010-01-01

    The gastrointestinal tracts (GITs) of six species of African mole-rats (Bathyergidae) were compared. The aim was to provide a comprehensive anatomical comparison between the different species. The relative shape, length, and surface areas were taken into account to determine whether the GITs are phylogenetically constrained or exhibit anatomical adaptations in response to diets. In all six species the stomach was simple and glandular. With the exception of Heterocephalus glaber, the caecum was coiled in a flat spiral, the ascending colon was arranged in a loop of varying lengths, and a mucosal colonic papillary-lined groove was present in the ascending colon in all species. By contrast, the caecum in H. glaber was uncoiled, the ascending colon was not looped, and the groove was not papillated. A caeco-appendix was observed only in Bathyergus suillus and Georychus capensis. Hierarchical multivariate cluster analysis on the presence/absence of nine anatomical structures associated with the GIT of mole-rats revealed that H. glaber was anatomically the least similar of the six species (77.6% similarity) with respect to the nine GIT variables included. All Cryptomys species were the same (100% similarity), and two species B. suillus and G. capensis grouped together and were more similar to the Cryptomys genus (95% similarity) than they were to H. glaber. These findings support previous phylogenetic classifications. The voluminous caeco-colon in B. suillus may be explained by its ingestion of grasses in addition to below-ground storage organs of plants. We conclude that phylogeny and diet affect the GIT anatomy of the African mole rats studied here.

  14. Revision of the Wind River faunas, early Eocene of central Wyoming. IX - The oldest known hystricomorphous rodent (Mammalia: Rodentia)

    NASA Technical Reports Server (NTRS)

    Dawson, Mary R.; Krishtalka, Leonard; Stucky, Richard K.

    1990-01-01

    The rostral portion of the skull of a new genus and species of rodent, Armintomys tullbergi, from the earliest middle Eocene of the Wind River Basin (Wyoming) provides the geologically oldest known record of the hystricomorphous zygomasseteric structure. Armintomys also preserves the oldest known occurrence of incisor enamel that is transitional from pauciserial to uniserial. Other dental characters include: anteriorly grooved incisor, small premolars, and relatively primitive sciuravidlike molars. Analysis of this unique combination of characters implies that Armintomys is the oldest known myomorph rodent and the only known representative of a new family. Armintomyidae, which is referred, with question, to the myomorph superfamily Dipodoidea. Armintomys is more primitive, especially in premolar retention and structure, than the Bridgerian zapodid Elymys from Nevada, but adds to evidence from the latter for an early origin and radiation of dipodoid rodents.

  15. Genetic assessment of the Atlantic Forest bristle porcupine, Chaetomys subspinosus (Rodentia: Erethizontidae), an endemic species threatened with extinction.

    PubMed

    Oliveira, C G; Martinez, R A; Giné, G A F; Faria, D M; Gaiotto, F A

    2011-05-24

    The bristle-spined porcupine, Chaetomys subspinosus, an endemic rodent from Atlantic Forest, was considered to be abundant in the recent past, but population reductions due to habitat loss and expansion of human activities caused this species to be included in the "vulnerable" category of the World Conservation Union Red List. We performed the first genetic assessment in natural populations of this focal species along its geographical distribution. Thirty-five non-invasive samples (hair) were collected from three natural populations in the Brazilian States of Sergipe, Bahia and Espírito Santo. Genetic similarity obtained by Jaccard's index, based on dominant RAPD and ISSR markers, varied between 25 and 100%. Four clusters, mainly coincident with the geographical distribution of the populations, were observed. Analysis of molecular variance based on 47 polymorphic loci showed that there was 15.99% genetic variability among populations and 84.01% within populations. The estimated genetic structure among populations (Φ(ST)) was 0.16. The populations may have formed a continuum along the past distribution of the Atlantic rainforest but historical events of human occupation resulted in recent divergence among sampled populations.

  16. Association of the "IUCN vulnerable" spiny rat Clyomys bishopi (Rodentia: Echimyidae) with palm trees and armadillo burrows in southeastern Brazil.

    PubMed

    Bueno, Adriana A; Lapenta, Marina J; Oliveira, Fátima; Motta-Junior, José C

    2004-12-01

    The globally vulnerable Clyomys bishopi, a semi-fossorial and colonial rodent, is apparently limited to cerrado (savannah-like vegetation) physiognomies in São Paulo State, Brazil. The aim of the study was to verify whether the presence of C. bishopi is associated to the occurrence of palm trees (Attalea gearensis, Syagrus loefgrenii) and armadillo burrows. Thirty six quadrats were placed in different physiognomies of cerrado vegetation at Itirapina Ecological Station, southeastern Brazil to survey the number of C. bishopi burrows of individuals of palm trees and burrows of armadillos. There was a strong dependence and association between the number of C. bishopi burrows and all measured variables (Contingency tables and Spearman rank correlations). It is suggested that this rodent can be found in great numbers where palm trees are abundant. The use of armadillo burrows possibly makes the movement of the rodents easier inside their own galleries.

  17. Two new species of Eimeria (Apicomplexa: Eimeriidae) from the mountain beaver, Aplodontia rufa (Rodentia: Aplodontiidae), from Oregon.

    PubMed

    McAllister, Chris T; Duszynski, Donald W; McKown, Richard D

    2013-06-01

    Two mountain beavers, Aplodontia rufa , were collected in Lincoln County, Oregon, and examined for coccidia. Both were infected with 2 new species of Eimeria. Oocysts of Eimeria chitkoae n. sp. were ellipsoidal with a bilayered wall and measured (L × W) 24.5 × 20.2 μm, with a shape index (SI) of 1.2. Both micropyle and oocyst residuum were absent, but a polar granule of several fragments was present. Sporocysts were ovoidal, 12.5 × 7.9 μm, SI was 1.6. Stieda and substieda bodies were present, but a parastieda body was absent; a sporocyst residuum was present, composed of a cluster of moderately coarse granules with many scattered fine granules. Stout sporozoites were 14.7 × 2.9 μm in situ, with spheroidal anterior and posterior refractile bodies. Oocysts of Eimeria lewisi n. sp. were ovoidal, with a smooth single-layered wall, and measured 13.7 × 7.8 μm, SI was 1.7. A micropyle and oocyst residuum were absent, but 1-2 polar granule(s) were present. Sporocysts were 6.6 × 4.2 μm, with SI of 1.6. A Stieda body was present, but substieda and parastieda bodies were absent; a sporocyst residuum was present, composed of a small cluster of several granules. Sporozoites were granular, 8.2 × 1.8 μm in situ, with a posterior refractile body. These are the first coccidians reported from the mountain beaver.

  18. Karyotype diversity suggests that Laonastes aenigmamus (Laotian rock rat) (Rodentia, Diatomyidae) is a multi-specific genus.

    PubMed

    Richard, Florence; Gerbault-Seureau, Michèle; Douangboupha, Bounneuang; Keovichit, Kham; Hugot, Jean-Pierre; Dutrillaux, Bernard

    2016-09-01

    Laonastes aenigmamus (Khanyou) is a recently described rodent species living in geographically separated limestone formations of the Khammuan Province in Lao PDR. Chromosomes of 21 specimens of L. aenigmamus were studied using chromosome banding as well as fluorescent in situ hybridization (FISH) techniques using human painting, telomere repeats, and 28S rDNA probes. Four different karyotypes were established. Study with human chromosome paints and FISH revealed that four large chromosomes were formed by multiple common tandem fusions, with persistence of some interstitial telomeres. The rearrangements separating the different karyotypes (I to IV) were also reconstructed. Various combinations of Robertsonian translocations or tandem fusions involving the same chromosomes differentiate these karyotypes. These rearrangements create a strong gametic barrier, which isolates specimens with karyotype II from the others. C-banding and FISH with telomere repeats also exhibit large and systematized differences between karyotype II and others. These data indicate an ancient reproductive separation and suggest that Laonastes is not a mono-specific genus.

  19. Cryptic Species in Proechimys goeldii (Rodentia, Echimyidae)? A Case of Molecular and Chromosomal Differentiation in Allopatric Populations.

    PubMed

    Rodrigues da Costa, Marlyson J; Siqueira do Amaral, Paulo J; Pieczarka, Julio C; Sampaio, Maria I; Rossi, Rogério V; Mendes-Oliveira, Ana C; Rodrigues Noronha, Renata C; Nagamachi, Cleusa Y

    2016-01-01

    The spiny rats of the genus Proechimys have a wide distribution in the Amazon, covering all areas of endemism of this region. We analyzed the karyotype and cytochrome b (Cyt b) sequences in Proechimys goeldii from 6 localities representing 3 interfluves of the eastern Amazon. A clear separation of P. goeldii into 2 monophyletic clades was observed, both chromosomally and based on Cyt b sequences: cytotype A (2n = 26x2640;/27x2642;, NF = 42) for samples from the Tapajos-Xingu interfluve and cytotype B (2n = 24x2640;/25x2642;, NF = 42) for samples from the Xingu-Tocantins interfluve and east of the Tocantins River. The karyotypes differ in a pericentric inversion and a centric fusion/fission and an average nucleotide divergence of 6.1%, suggesting cryptic species. Meiotic analysis confirmed the presence of a XX/XY1Y2 multiple sex chromosome determination system for both karyotypes. The karyotypes also vary from the literature (2n = 24, NF = 42, XX/XY). The autosome translocated to the X chromosome is different both in size and morphology to P. cf. longicaudatus, which also has a multiple sex chromosome determination system (2n = 14x2640;/15x2640;x2642;/16x2640;/17x2642;, NF = 14). The Xingu River is a barrier that separates populations of P. goeldii, thus maintaining their allopatric nature and providing an explanation for the molecular and cytogenetic patterns observed for the Xingu River but not the Tocantins River.

  20. Demodex castoris sp. nov. (Acari: Demodecidae) parasitizing Castor fiber (Rodentia), and other parasitic arthropods associated with Castor spp.

    PubMed

    Izdebska, Joanna N; Fryderyk, Sławomira; Rolbiecki, Leszek

    2016-02-11

    A new species of demodecid mite, Demodex castoris sp. nov. (Acari: Prostigmata: Demodecidae), is described based on adult stages from the skin of the nasal region of the Eurasian beaver Castor fiber Linnaeus, 1758, collected in Poland. This is the first detection of a representative demodecid mite in rodents of the suborder Castorimorpha and also represents the first detection of a skin mite in Eurasian beavers. The new species is a small skin mite (average 173 µm in length) characterized by sexual dimorphism related to body proportions. D. castoris sp. nov. was observed in 4 out of 6 beavers examined (66.6%), with a mean intensity of 10.8 and an intensity range of 2-23 ind. host(-1). This paper also contains a checklist of parasitic arthropods known from Castor spp.

  1. A new species of Trichuris Roederer, 1761 (Nematoda: Trichuridae) from Heteromys gaumeri Allen & Chapman (Rodentia: Heteromyidae) in Yucatan, Mexico.

    PubMed

    Panti-May, Jesús Alonso; Robles, María Del Rosario

    2016-09-01

    In Mexico, four species of Trichuris Roederer, 1761 have been recorded in wild rodents belonging to the family Heteromyidae. In the present paper, we describe a new species based on specimens collected from Heteromys gaumeri Allen & Chapman (Heteromyidae: Heteromyinae) in the tropical forests of the Yucatan Peninsula, Mexico. Trichuris silviae n. sp. can be differentiated from the congeners described in North and South American rodents by morphological and morphometric features, such as the possession of a wide spicular tube, a thicker proximal cloacal tube, a shorter distal cloacal tube and a cylindrical spicular sheath. This is the first description of a Trichuris spp. from heteromyid rodents in Mexico and the fourth in North America. Despite the broad distribution of Heteromys spp., few cases of Trichuris infection have been reported. Further studies are necessary to verify if the new species is present in other heteromyid rodents in order to increase our knowledge about its geographical and host distribution.

  2. Comparison of climate space and phylogeny of Marmota (Mammalia: Rodentia) indicates a connection between evolutionary history and climate preference.

    PubMed

    Davis, Edward Byrd

    2005-03-07

    Palaeobiologists have investigated the evolutionary responses to extinct organisms to climate change, and have also used extinct organisms to reconstruct palaeoclimates. There is evidence of a disconnection between climate change and evolution that suggest that organism may not be accurate paleoclimate indicators. Here, marmots (Marmota sp.) are used as a case study to examine whether similarity of climate preferences is correlated with evolutionary relatedness of species. This study tests for a relationship between phylogenetic distance and 'climate distance' of species with a clade. There should be a significant congruence between maximus likelihood distance and standardized Euclidian distance between climates if daughter species tend to say in environments similar to parent species. Marmots make a good test case because there are many extant species, their phylogenetics are well established and individual survival is linked to climatic factors. A Mantel test indicates a significant correlation between climate and phylogenetic distance matrices, but this relationship explains only a small fraction of the variance (regression R(2) = 0.114). These results that (i) closely related species of marmots tend to stay in similar environments; (ii) marmots may be more susceptible than may mammals to global climate change; and (iii) because of the considerable noise in this system, the correlation cannot be used for detailed palaeoclimate reconstruction.

  3. Evolutionary acceleration in the most endangered mammal of Canada: speciation and divergence in the Vancouver Island marmot (Rodentia, Sciuridae).

    PubMed

    Cardini, A; Thorington, R W; Polly, P D

    2007-09-01

    The Vancouver Island marmot is the most endangered mammal of Canada. Factors which have brought this population to the verge of extinction have not yet been fully elucidated, but the effects of deforestation and habitat fragmentation on survival rates, as well as those of variation in rainfall, temperature, snowpack depth and snowmelt strongly suggest that marmots on the island are struggling to keep pace with environmental changes. Genetic analyses, however, seem to indicate that the Vancouver Island marmot may merely represent a melanistic population of its parental species on the mainland. Were it not for its black pelage colour, it is unlikely that it would have attracted much attention as a conservation priority. Our study uses three-dimensional coordinates of cranial landmarks to further assess phenotypic differentiation of the Vancouver Island marmot. A pattern of strong interspecific divergence and low intraspecific variation was found which is consistent with aspects of drift-driven models of speciation. However, the magnitude of shape differences relative to the putatively neutral substitutions in synonymous sites of cytochrome b is too large for being compatible with a simple neutral model. A combination of bottlenecks and selective pressures due to natural and human-induced changes in the environment may offer a parsimonious explanation for the large phenotypic differentiation observed in the species. Our study exemplifies the usefulness of a multidisciplinary approach to the study of biological diversity for a better understanding of evolutionary models and to discover aspects of diversity that may be undetected by using only a few genetic markers to characterize population divergence and uniqueness.

  4. In the Wake of Invasion: Tracing the Historical Biogeography of the South American Cricetid Radiation (Rodentia, Sigmodontinae)

    PubMed Central

    Leite, Rafael N.; Kolokotronis, Sergios-Orestis; Almeida, Francisca C.; Werneck, Fernanda P.; Rogers, Duke S.; Weksler, Marcelo

    2014-01-01

    The Great American Biotic Interchange (GABI) was greatly influenced by the completion of the Isthmus of Panama and impacted the composition of modern faunal assemblages in the Americas. However, the contribution of preceding events has been comparatively less explored, even though early immigrants in the fossil records are evidence for waif dispersals. The cricetid rodents of the subfamily Sigmodontinae are a classic example of a species-rich South American radiation resulting from an early episode of North American invasion. Here, we provide a temporal and spatial framework to address key aspects of the historical biogeography and diversification of this diverse mammal group by using mitochondrial and nuclear DNA datasets coupled with methods of divergence time estimation, ancestral area reconstruction and comparative phylogenetics. Relaxed-clock time estimates indicate that divergence of the Sigmodontinae began in the middle–late Miocene (ca. 12–9 Ma). Dispersal-vicariance analyses point to the arrival of a single lineage of northern invaders with a widespread ancestral distribution and imply that the initial differentiation between Central and South America gave rise to the most basal groups within the subfamily. These two major clades diversified in the late Miocene followed by the radiation of main tribes until the early Pliocene. Within the Oryzomyalia, tribes diverged initially in eastern South America whereas multiple dispersals into the Andes promoted further diversification of the majority of modern genera. A comparatively uniform background tempo of diversification explains the species richness of sigmodontines across most nodes, except for two akodontine genera with recent increases in diversification rates. The bridging of the Central American seaway and episodes of low sea levels likely facilitated the invasion of South America long before the onset of the post-Isthmian phase of the GABI. PMID:24963664

  5. Host cell/Orientia tsutsugamushi interactions: evolution and expression of syndecan-4 in Asian rodents (Rodentia, Muridae).

    PubMed

    Badenhorst, Daleen; Tatard, Caroline; Suputtamongkol, Yupin; Robinson, Terence J; Dobigny, Gauthier

    2012-07-01

    Scrub typhus is an acute febrile zoonotic disease and worldwide more than a billion people may be at risk for infection. Orientia tsutsugamushi, the causative agent of scrub typhus, is an obligate intracellular bacterium. Rodents are reported to be the primary reservoir hosts of the disease and according to the most recent surveys, all species within the Rattus sensu lato complex of the tribe Rattini are carriers of scrub typhus. There is no evidence that any of mouse (Mus) species serves as the primary reservoir of the bacterium even when occurring in sympatry with wild infected rats. This contrast in the host/syndecan-4 interactions between Rattini and Asian Murini may be due to intrinsic (i.e., genetic) differences. Herein we compare the sequence and expression levels of syndecan-4 (the putative cell receptor of O. tsutsugamushi) between Rattini species that are known to be natural reservoirs for the typhus agents, and Murini species that are not. Although it was not possible to conclusively link the structural variations detected in syndecan-4 with carrier status in either Rattini and Murini, our findings indicate the absence of a strong Orientia-mediated selective regime acting on gene structure. In contrast, variable spleen-specific syndecan-4 expression levels show a strong correlation between under-expression of syndecan-4 in Murini and seropositive Rattini, compared to seronegative Rattini rodents. We postulate that two divergent responses may be at work in Murini and Rattini, both linked with differential expression of syndecan-4: (i) reduced syndecan-4 transcription in Murini decreases the likelihood that the host cells will become infected by the Orientia bacterium, while (ii) reduced syndecan-4 expression in seropositive Rattini limits the pathogenicity of Orientia and consequently improves the longevity of the rat hosts. These patterns may underpin the poor carrier status of wild mice on the one hand, and the effective role of wild rats as reservoir hosts on the other.

  6. [Morphological diversity in the postnatal skull development in representatives of two families of rodents (Spalacidae, Castoridae, Rodentia)].

    PubMed

    Puzachenko, A Iu; Korablev, N P

    2014-01-01

    This is the first study to describe the results of measurement of three information parameters of morphological diversity (entropy, the measure of organization, and the Kullback-Leibler divergence) in the course of postnatal development of the skull in the populations of two rodent species (greater mole rat (Spalax microphthalmus Guld.) and Eurasian beaver (Castor fiber (L.)). The terms "morphosystem" and "morphological space" and its structure are introduced. Within the framework of the developed approach, "morphological diversity" is considered as a variable associated with the morphological space structure. Testing the hypothesis of the dominance of self-organization processes and an increase in the organization of the morphological diversity of the skull in the course ofontogeny showed its inconsistency. The morphosystem of the skull of the studied species undergoes transitions between more organized and less organized states, periodically approaching and departing from the "steady state." Such dynamics characterizes the morphosystem of the skull as a dynamic and nonlinear system.

  7. Assessment of Three Mitochondrial Genes (16S, Cytb, CO1) for Identifying Species in the Praomyini Tribe (Rodentia: Muridae)

    PubMed Central

    Nicolas, Violaine; Schaeffer, Brigitte; Missoup, Alain Didier; Kennis, Jan; Colyn, Marc; Denys, Christiane; Tatard, Caroline; Cruaud, Corinne; Laredo, Catherine

    2012-01-01

    The Praomyini tribe is one of the most diverse and abundant groups of Old World rodents. Several species are known to be involved in crop damage and in the epidemiology of several human and cattle diseases. Due to the existence of sibling species their identification is often problematic. Thus an easy, fast and accurate species identification tool is needed for non-systematicians to correctly identify Praomyini species. In this study we compare the usefulness of three genes (16S, Cytb, CO1) for identifying species of this tribe. A total of 426 specimens representing 40 species (sampled across their geographical range) were sequenced for the three genes. Nearly all of the species included in our study are monophyletic in the neighbour joining trees. The degree of intra-specific variability tends to be lower than the divergence between species, but no barcoding gap is detected. The success rate of the statistical methods of species identification is excellent (up to 99% or 100% for statistical supervised classification methods as the k-Nearest Neighbour or Random Forest). The 16S gene is 2.5 less variable than the Cytb and CO1 genes. As a result its discriminatory power is smaller. To sum up, our results suggest that using DNA markers for identifying species in the Praomyini tribe is a largely valid approach, and that the CO1 and Cytb genes are better DNA markers than the 16S gene. Our results confirm the usefulness of statistical methods such as the Random Forest and the 1-NN methods to assign a sequence to a species, even when the number of species is relatively large. Based on our NJ trees and the distribution of all intraspecific and interspecific pairwise nucleotide distances, we highlight the presence of several potentially new species within the Praomyini tribe that should be subject to corroboration assessments. PMID:22574186

  8. Genetic Pool Information Reflects Highly Suitable Areas: The Case of Two Parapatric Endangered Species of Tuco-tucos (Rodentia: Ctenomiydae)

    PubMed Central

    Galiano, Daniel; Bernardo-Silva, Jorge; de Freitas, Thales R. O.

    2014-01-01

    Conservation of small mammals requires knowledge of the genetically and ecologically meaningful spatial scales at which species respond to habitat modifications. Conservation strategies can be improved through the use of ecological niche models and genetic data to classify areas of high environmental suitability. In this study, we applied a Maxent model integrated with genetic information (nucleotide diversity, haplotype diversity and Fu's Fs neutrality tests) to evaluate potential genetic pool populations with highly suitable areas for two parapatric endangered species of tuco-tucos (Ctenomys minutus and C. lami). Our results demonstrated that both species were largely influenced by vegetation and soil variables at a landscape scale and inhabit a highly specific niche. Ctenomys minutus was also influenced by the variable altitude; the species was associated with low altitudes (sea level). Our model of genetic data associated with environmental suitability indicate that the genetic pool data were associated with highly suitable areas for C. minutus. This pattern was not evident for C. lami, but this outcome could be a consequence of the restricted range of the species. The preservation of species requires not only detailed knowledge of their natural history and genetic structure but also information on the availability of suitable areas where species can survive, and such knowledge can aid significantly in conservation planning. This finding reinforces the use of these two techniques for planning conservation actions. PMID:24819251

  9. A taxonomic review of hymenolepidids (Eucestoda, Hymenolepididae) from dormice (Rodentia, Gliridae), with descriptions of two new species.

    PubMed

    Makarikov, Arseny A

    2017-03-01

    In present study the systematic and taxonomic position of hymenolepidids parasitizing rodents of the family Gliridae from Europe and Central Asia is discussed. Hymenolepis myoxi is redescribed on the basis of the type material from the fat dormouse Glis glis deposited in the collection of the Museum für Naturkunde, Berlin, Germany. Significant corrections of morphologically distinctive characters attributable to H. myoxi include: (1) recognition of a rudimentary rostellar apparatus; (2) absence of rostellar hooks and spination on the suckers; and (3) tissues of the scolex and neck filled with numerous "firm elements". Hymenolepis sulcata was recognised as a synonym of H. myoxi (sensu stricto). The generic allocation of true H. myoxi and validity of the genus Armadolepis is clarified. Specimens from Eliomys quercinus originally designated as H. myoxi by Baer (1932) are described as a new species, Armadolepis jeanbaeri n. sp. The taxonomy has potentially been confused as Spassky (1954) designated misidentified specimens of H. myoxi sensu Baer (1932) as the type species of the genus Armadolepis. In the current article, this error is corrected and A. jeanbaeri n. sp. is fixed as the type of the genus Armadolepis. An additional new species of Armadolepis, A. tenorai n. sp., is described from Dryomys nitedula from Almaty Province, Kazakhstan. The generic diagnosis of Armadolepis is amended. Armadolepis (sensu stricto) is subdivided into two subgenera; the nominotypical subgenus includes species having well developed rostellar apparatus armed by rostellar hooks and A. (Bremserilepis) n. subgen. includes species with rudimentary and unarmed rostellar apparatus.

  10. Dating an impressive Neotropical radiation: Molecular time estimates for the Sigmodontinae (Rodentia) provide insights into its historical biogeography.

    PubMed

    Parada, Andrés; Pardiñas, Ulyses F J; Salazar-Bravo, Jorge; D'Elía, Guillermo; Palma, R Eduardo

    2013-03-01

    With about 400 living species and 82 genera, rodents of the subfamily Sigmodontinae comprise one of the most diverse and more broadly distributed Neotropical mammalian clades. There has been much debate on the origin of the lineage or the lineages of sigmodontines that entered South America, the timing of entrance and different aspects of further diversification within South America. The ages of divergence of the main lineages and the crown age of the subfamily were estimated by using sequences of the interphotoreceptor retinoid binding protein and cytochrome b genes for a dense sigmodontine and muroid sampling. Bayesian inference using three fossil calibration points and a relaxed molecular clock estimated a middle Miocene origin for Sigmodontinae (∼12Ma), with most tribes diversifying throughout the Late Miocene (6.9-9.4Ma). These estimates together results of analyses of ancestral area reconstructions suggest a distribution for the most recent common ancestor of Sigmodontinae in Central-South America and a South American distribution for the most recent common ancestor of Oryzomyalia.

  11. Evolutionary and Biological Implications of Dental Mesial Drift in Rodents: The Case of the Ctenodactylidae (Rodentia, Mammalia)

    PubMed Central

    Gomes Rodrigues, Helder; Solé, Floréal; Charles, Cyril; Tafforeau, Paul; Vianey-Liaud, Monique; Viriot, Laurent

    2012-01-01

    Dental characters are importantly used for reconstructing the evolutionary history of mammals, because teeth represent the most abundant material available for the fossil species. However, the characteristics of dental renewal are presently poorly used, probably because dental formulae are frequently not properly established, whereas they could be of high interest for evolutionary and developmental issues. One of the oldest rodent families, the Ctenodactylidae, is intriguing in having longstanding disputed dental formulae. Here, we investigated 70 skulls among all extant ctenodactylid genera (Ctenodactylus, Felovia, Massoutiera and Pectinator) by using X-ray conventional and synchrotron microtomography in order to solve and discuss these dental issues. Our study clearly indicates that Massoutiera, Felovia and Ctenodactylus differ from Pectinator not only by a more derived dentition, but also by a more derived eruptive sequence. In addition to molars, their dentition only includes the fourth deciduous premolars, and no longer bears permanent premolars, conversely to Pectinator. Moreover, we found that these premolars are lost during adulthood, because of mesial drift of molars. Mesial drift is a striking mechanism involving migration of teeth allowed by both bone remodeling and dental resorption. This dental innovation is to date poorly known in rodents, since it is only the second report described. Interestingly, we noted that dental drift in rodents is always associated with high-crowned teeth favoring molar size enlargement. It can thus represent another adaptation to withstand high wear, inasmuch as these rodents inhabit desert environments where dust is abundant. A more accurate study of mesial drift in rodents would be very promising from evolutionary, biological and orthodontic points of view. PMID:23185576

  12. Syphacia (Syphacia) maxomyos sp. n. (Nematoda: Oxyuridae) from Maxomys spp. (Rodentia: Muridae) from Sulawesi and Sumatra, Indonesia

    PubMed Central

    DEWI, Kartika; HASEGAWA, Hideo; FITRIANA, Yuli Sulistya; ASAKAWA, Mitsuhiko

    2015-01-01

    The present report describes Syphacia (Syphacia) maxomyos sp. n. (Nematoda: Oxyuridae) from two species of spiny rats, Maxomys musschenbroekii from Sulawesi and M. whiteheadi from Sumatra. It is characterized by a cephalic plate extending laterally with dorsoventral constriction and stumpy eggs with an operculum rim reaching pole. It is readily distinguishable by the former feature from all of hitherto known representatives of this genus in Indonesia, but it resembles parasites in Murini and Hydromyni rodents in continental Asia and Sahul. This is the first Syphacia species distributed in both the Sunda Shelf and Sulawesi with the exception of Syphacia muris, a cosmopolitan pinworm found in rodents of the of genus Rattus. It is surmised that S. maxomyos is specific to Maxomys and that it was introduced to Sulawesi by dispersal of some Maxomys from the Sunda Shelf. PMID:26062434

  13. The impact of gape on the performance of the skull in chisel-tooth digging and scratch digging mole-rats (Rodentia: Bathyergidae)

    PubMed Central

    McIntosh, Andrew F.

    2016-01-01

    The African mole-rats (Bathyergidae) are a family of rodents highly adapted for life underground. Previous research has shown that chisel-tooth digging mole-rats (which use their incisors to dig burrows) are clearly distinguishable from scratch diggers (which only use the forelimbs to tunnel) on the basis of morphology of the skull, and that the differences are linked to the production of high bite forces and wide gapes. We hypothesized that the skull of a chisel-tooth digging mole-rat would perform better at wider gapes than that of a scratch digging mole-rat during incisor biting. To test this hypothesis, we created finite-element models of the cranium of the scratch digging Bathyergus suillus and the chisel-tooth digging Fukomys mechowii, and loaded them to simulate incisor bites at different gapes. Muscle loads were scaled such that the ratio of force to surface area was the same in both models. We measured three performance variables: overall stress across the cranium, mechanical efficiency of biting and degree of deformation across the skull. The Fukomys model had a more efficient incisor bite at all gapes, despite having greater average stress across the skull. In addition, the Fukomys model deformed less at wider gapes, whereas the Bathyergus model deformed less at narrower gapes. These properties of the cranial morphology of Fukomys and Bathyergus are congruent with their respective chisel-tooth and scratch digging behaviours and, all other factors being equal, would enable the more efficient production of bite force at wider gapes in Fukomys. However, in vivo measurements of muscle forces and activation patterns are needed to fully understand the complex biomechanics of tooth digging. PMID:27853575

  14. [A modular approach to studying of fluctuating asymmetry of complex morphological structures in rodents with the mandible of the bank vole (Clethrionomys glareolus, Arvicolinae, Rodentia) as an example].

    PubMed

    Ialkovskaia, L É; Borodin, A V; Fominykh, M A

    2014-01-01

    The expediency of a modular approach to estimating fluctuating asymmetry (FA) of complex morphological structures was shown using the mandible of the bank vole (Clethrionomys glareolus Schreber, 1780) as an example. FA of the shape of two mandibular regions (modules) defined developmentally and functionally, was assessed by means of geometric morphometrics. The differences between mandibular regions in the FA levels were found for both individual landmarks and integral indices of asymmetry. Regardless of age, gender or sampling year, FA estimates obtained for posterior region including part of the ramus and processes were higher than those for anterior region including the diastemal area. The results suggest that modularity of complex morphological structures should be taken into account when analyzing FA.

  15. Development of nine new microsatellite loci for the American beaver, Castor canadensis (Rodentia: Castoridae), and cross-species amplification in the European beaver, Castor fiber.

    PubMed

    Pelz-Serrano, Karla; Munguia-Vega, Adrian; Piaggio, Antoinette J; Neubaum, Melissa; Munclinger, Pavel; Pártl, Adam; VAN Riper Iii, Charles; Culver, Melanie

    2009-03-01

    We developed nine new nuclear dinucleotide microsatellite loci for Castor canadensis. All loci were polymorphic, except for one. The number of alleles ranged from two to four and from five to 12 in populations from Arizona and Wisconsin, respectively. Average heterozygosity ranged from 0.13 to 0.86 per locus. Since cross-species amplification in Castor fiber was successful only in four loci, we tested also nine recently published C. canadensis loci in the Eurasian species. Eight of the published loci amplified; however, three were monomorphic. The number of alleles was lower in C. fiber than in C. canadensis at all loci tested.

  16. Stratigraphic context and paleoenvironmental significance of minor taxa (Pisces, Reptilia, Aves, Rodentia) from the late Early Pleistocene paleoanthropological site of Buia (Eritrea).

    PubMed

    Rook, L; Ghinassi, M; Carnevale, G; Delfino, M; Pavia, M; Bondioli, L; Candilio, F; Coppa, A; Martínez-Navarro, B; Medin, T; Papini, M; Zanolli, C; Libsekal, Y

    2013-01-01

    The Buia Homo site, also known as Wadi Aalad, is an East African paleoanthropological site near the village of Buia that, due to its very rich yield from the late Early Pleistocene, has been intensively investigated since 1994. In this paper, which reports on the finds of the 2010-2011 excavations, we include new fossil evidence on previously identified taxa (i.e., reptiles), as well as the very first description of the small mammal, fish and bird remains discovered. In particular, this study documents the discovery of the first African fossil of the genus Burhinus (Aves, Charadriiformes) and of the first rodent from the site. This latter is identified as a thryonomyid rodent (cane rat), a relatively common taxon in African paleoanthropological faunal assemblages. On the whole, the new occurrences documented within the Buia vertebrate assemblage confirm the occurrence of taxa characterized by strong water dependence. The paleoenvironmental characteristics of the fauna are confirmed as fully compatible with the evidence obtained through sedimentology and facies analysis, documenting the sedimentary evolution of fluvio-deltaic and lacustrine systems.

  17. Biome specificity of distinct genetic lineages within the four-striped mouse Rhabdomys pumilio (Rodentia: Muridae) from southern Africa with implications for taxonomy.

    PubMed

    du Toit, Nina; van Vuuren, Bettine Jansen; Matthee, Sonja; Matthee, Conrad A

    2012-10-01

    Within southern Africa, a link between past climatic changes and faunal diversification has been hypothesized for a diversity of taxa. To test the hypothesis that evolutionary divergences may be correlated to vegetation changes (induced by changes in climate), we selected the widely distributed four-striped mouse, Rhabdomys, as a model. Two species are currently recognized, the mesic-adapted R. dilectus and arid-adapted R. pumilio. However, the morphology-based taxonomy and the distribution boundaries of previously described subspecies remain poorly defined. The current study, which spans seven biomes, focuses on the spatial genetic structure of the arid-adapted R. pumilio (521 specimens from 31 localities), but also includes limited sampling of the mesic-adapted R. dilectus (33 specimens from 10 localities) to act as a reference for interspecific variation within the genus. The mitochondrial COI gene and four nuclear introns (Eef1a1, MGF, SPTBN1, Bfib7) were used for the construction of gene trees. Mitochondrial DNA analyses indicate that Rhabdomys consists of four reciprocally monophyletic, geographically structured clades, with three distinct lineages present within the arid-adapted R. pumilio. These monophyletic lineages differ by at least 7.9% (±0.3) and these results are partly confirmed by a multilocus network of the combined nuclear intron dataset. Ecological niche modeling in MaxEnt supports a strong correlation between regional biomes and the distribution of distinct evolutionary lineages of Rhabdomys. A Bayesian relaxed molecular clock suggests that the geographic clades diverged between 3.09 and 4.30Ma, supporting the hypothesis that the radiation within the genus coincides with paleoclimatic changes (and the establishment of the biomes) characterizing the Miocene-Pliocene boundary. Marked genetic divergence at the mitochondrial DNA level, coupled with strong nuclear and mtDNA signals of non-monophyly of R. pumilio, support the notion that a taxonomic revision of the genus is needed.

  18. Panic-like defensive behavior but not fear-induced antinociception is differently organized by dorsomedial and posterior hypothalamic nuclei of Rattus norvegicus (Rodentia, Muridae)

    PubMed Central

    Biagioni, A.F.; Silva, J.A.; Coimbra, N.C.

    2012-01-01

    The hypothalamus is a forebrain structure critically involved in the organization of defensive responses to aversive stimuli. Gamma-aminobutyric acid (GABA)ergic dysfunction in dorsomedial and posterior hypothalamic nuclei is implicated in the origin of panic-like defensive behavior, as well as in pain modulation. The present study was conducted to test the difference between these two hypothalamic nuclei regarding defensive and antinociceptive mechanisms. Thus, the GABAA antagonist bicuculline (40 ng/0.2 µL) or saline (0.9% NaCl) was microinjected into the dorsomedial or posterior hypothalamus in independent groups. Innate fear-induced responses characterized by defensive attention, defensive immobility and elaborate escape behavior were evoked by hypothalamic blockade of GABAA receptors. Fear-induced defensive behavior organized by the posterior hypothalamus was more intense than that organized by dorsomedial hypothalamic nuclei. Escape behavior elicited by GABAA receptor blockade in both the dorsomedial and posterior hypothalamus was followed by an increase in nociceptive threshold. Interestingly, there was no difference in the intensity or in the duration of fear-induced antinociception shown by each hypothalamic division presently investigated. The present study showed that GABAergic dysfunction in nuclei of both the dorsomedial and posterior hypothalamus elicit panic attack-like defensive responses followed by fear-induced antinociception, although the innate fear-induced behavior originates differently in the posterior hypothalamus in comparison to the activity of medial hypothalamic subdivisions. PMID:22437484

  19. Hepatic parasitosis in two wood mice, Apodemus sylvaticus (Rodentia: Muridae), due to Aonchotheca annulosa (Nematoda: Trichuridae), and Eucoleus bacillatus (Nematoda: Trichuridae). Erratic parasitism or post mortem migration?

    PubMed

    Debenedetti, Ángela L; Sáez-Durán, Sandra; Sainz-Elipe, Sandra; Galán-Puchades, Maria Teresa; Fuentes, Màrius V

    2014-10-01

    Aonchotheca annulosa and Eucoleus bacillatus are two capillariin nematodes parasitizing the intestinal and stomach mucosa, respectively, of various rodent species, and two, among others, component species of the helminth fauna of the wood mouse, Apodemus sylvaticus. A capillariin each was found in the liver parenchyma of two wood mice in a post-fire regeneration enclave in Serra Calderona Natural Park (Valencian Community, Spain). Due to their location, the preliminary identification of the helminths corresponded to Calodium hepaticum, a hepatic capillariin with rodents as its main host. So far, this species had never been found in Serra Calderona. To verify the preliminary identification, a comparative morphometric study between the specimens from Serra Calderona and a preserved individual of C. hepaticum from another enclave was carried out. Morphometric analysis revealed that the adult helminth as well as the eggs found in the liver of the first mouse belonged to A. annulosa, whereas the second one was identified as a male E. bacillatus. Moreover, the liver from both hosts showed a visible pathology, being the consequence of aberrant migration of the parasites. This is the first evidence that A. annulosa and E. bacillatus may migrate erratically and thus produce ectopic foci in other organs.

  20. Syphacia sp. (Nematoda: Oxyuridae) in coprolites of Kerodon rupestris Wied, 1820 (Rodentia: Caviidae) from 5,300 years BP in northeastern Brazil.

    PubMed

    Souza, Mônica Vieira de; Sianto, Luciana; Chame, Marcia; Ferreira, Luiz Fernando; Araújo, Adauto

    2012-06-01

    We present the results of paleoparasitological analyses in coprolites of Kerodon rupestris, rodent endemic to rocky areas of Brazil's semiarid region. The coprolites were collected from excavations at the archaeological site of Toca dos Coqueiros, in the National Park of Serra da Capivara, southeastern of state of Piauí. Syphacia sp. (Nematoda: Oxyuridae) eggs were identified in coprolites dated at 5,300 ± 50 years before present. This is the first record of the genus Syphacia in rodent coprolites in the Americas.

  1. The role of chromosomal rearrangements and geographical barriers in the divergence of lineages in a South American subterranean rodent (Rodentia: Ctenomyidae: Ctenomys minutus).

    PubMed

    Lopes, C M; Ximenes, S S F; Gava, A; de Freitas, T R O

    2013-10-01

    Identifying factors and the extent of their roles in the differentiation of populations is of great importance for understanding the evolutionary process in which a species is involved. Ctenomys minutus is a highly karyotype-polymorphic subterranean rodent, with diploid numbers ranging from 42 to 50 and autosomal arm numbers (ANs) ranging from 68 to 80, comprising a total of 45 karyotypes described so far. This species inhabits the southern Brazilian coastal plain, which has a complex geological history, with several potential geographical barriers acting on different time scales. We assessed the geographical genetic structure of C. minutus, examining 340 individuals over the entire distributional range and using information from chromosomal rearrangements, mitochondrial DNA (mtDNA) sequences and 14 microsatellite loci. The mtDNA results revealed seven main haplogroups, with the most recent common ancestors dating from the Pleistocene, whereas clustering methods defined 12 populations. Some boundaries of mtDNA haplogroups and population clusters can be associated with potential geographical barriers to gene flow. The isolation-by-distance pattern also has an important role in fine-scale genetic differentiation, which is strengthened by the narrowness of the coastal plain and by common features of subterranean rodents (that is, small fragmented populations and low dispersal rates), which limit gene flow among populations. A step-by-step mechanism of chromosomal evolution can be suggested for this species, mainly associated with the metapopulation structure, genetic drift and the geographical features of the southern Brazilian coastal plain. However, chromosomal variations have no or very little role in the diversification of C. minutus populations.

  2. Four new coccidia (Apicomplexa: Eimeriidae) from the Plateau zokor, Myospalax baileyi Thomas (Rodentia: Myospalacinae), a subterranean rodent from Haibei area, Qinghai Province, China.

    PubMed

    Cao, Yi-Fan; Nie, Xu-Heng; Zhang, Tong-Zuo; Du, Shou-Yang; Duszynski, Donald W; Bian, Jiang-Hui

    2014-02-01

    Thirty-eight faecal samples from the Plateau zokor, Myospalax baileyi Thomas, collected in the Haibei Area, Qinghai Province, China, were examined for the presence of coccidia (Apicomplexa: Eimeriidae). Seventeen of 38 faecal samples (44.7%) were found to contain coccidian oöcysts representing four new species of Eimeria Schneider, 1875, and four of 17 (23.5%) infected zokors were concurrently infected with two or three of these eimerian species. The sporulated oöcysts of Eimeria myospalacensis n. sp. are ovoidal, 9.5-17.0 × 8.0-13.0 (mean 13.0 × 10.4) μm; a polar granule is present, oöcyst residuum is absent; sporocysts are ovoidal, 4.5-7.5 × 3.0-5.0 (mean 6.3 × 4.2) μm and have both a Stieda body and residuum. Oöcysts of Eimeria fani n. sp. are ellipsoidal to cylindroidal, 12.5-16.0 × 8.0-11.0 (mean 14.6 × 9.9) μm; a polar granule is present, but micropyle and residuum are lacking; sporocysts are ovoidal, 4.5-7.5 × 3.0-5.3 (mean 6.7 × 4.4) μm; a residuum and a Steida body are present. Oöcysts of Eimeria baileyii n. sp. are ellipsoidal, 15.0-23.0 × 12.0-18.0 (mean 18.2 × 13.7) μm; a polar granule is present but oöcyst residuum is absent; sporocysts are ovoidal, 8.0-11.0 × 5.0-7.0 (mean 9.5 × 5.9) μm and have both a Stieda body and residuum. Oöcysts of Eimeria menyuanensis n. sp. are ovoidal, 12.5-21.0 × 11.0-18.0 (mean 17.1 × 14.6) μm, with a distinct micropyle c.2.5 μm wide; a polar granule is present but a residuum is absent; sporocysts are ovoidal, 8.0-12.0 × 5.0-7.0 (mean 10.2 × 6.4) μm, and have both a Stieda body and residuum.

  3. Phylogeny and temporal diversification of Calomys (Rodentia, Sigmodontinae): implications for the biogeography of an endemic genus of the open/dry biomes of South America.

    PubMed

    Almeida, Francisca C; Bonvicino, Cibele R; Cordeiro-Estrela, Pedro

    2007-02-01

    A thorough analysis of character evolution and biogeography of a group is only possible with a comprehensive sampling of its diversity. The sigmodontine genus Calomys is particularly interesting for the study of neotropical biogeography as it occurs exclusively in the dry and grassland biomes: Cerrado, Caatinga, Chaco, Pampas, Venezuelan Llanos, Puna, and a diversity of dry forests biomes. Although Brazil encompasses a large part of the geographic distribution of the genus and at least three endemic species, the last published phylogeny of Calomys included only two specimens (both representing the same species) from a single locality in this country. In the present paper we add complete cytochrome b sequences of Brazilian karyomorphs to previously published sequences in order to provide a phylogenetic hypothesis including most of the genus diversity. The main objectives of this study were to clarify taxonomic issues related to Brazilian karyomorphs and to study the diversification processes of the genus by analyzing its biogeography in combination with cladogenesis dates estimated with a molecular clock. The phylogeny indicates that at least six different species inhabit the Brazilian territory, one of them still undescribed. Date estimates indicate that two sequential basal splits, the first separating Andean from lowland species and the second isolating species north and south of the Amazonia, took place in the Pliocene between 3 and 4 Ma. A large-bodied and speciose clade of lowland species associated with dry forests and ecotones of the core Cerrado and Chaco areas with adjacent biomes diversified in the Pleistocene. This indicates the importance of safeguarding ecotones and the Cerrado at a time where this biome is being rapidly destroyed.

  4. Variation in progesterone receptors and GnRH expression in the hypothalamus of the pregnant South American plains vizcacha, Lagostomus maximus (Mammalia, Rodentia).

    PubMed

    Dorfman, Verónica Berta; Saucedo, Lucía; Di Giorgio, Noelia Paula; Inserra, Pablo Ignacio Felipe; Fraunhoffer, Nicolás; Leopardo, Noelia Paola; Halperín, Julia; Lux-Lantos, Victoria; Vitullo, Alfredo Daniel

    2013-11-01

    In mammals, elevated levels of progesterone (P4) throughout gestation maintain a negative feedback over the hypothalamic-hypophyseal-gonadal (H-H-G) axis, avoiding preovulatory follicular growth and preventing ovulation. Recent studies showed that in the South American plains vizcacha (Lagostomus maximus) folliculogenesis progresses to preovulatory stages during gestation, and an ovulatory process seems to occur at midgestation. The aim of this work was to analyze hypothalamic gonadotropin-releasing hormone (GnRH) and P4 receptors (PR) expression and luteinizing hormone (LH) secretion and correlate these with the functional state of the ovary in nonovulating and ovulating females and gestating females with special emphasis in the supposedly ovulating females at midgestation. We investigated P4 and LH serum levels as well as the distribution, localization, and expression of PR and GnRH in the hypothalamus of L. maximus at different time points during gestation and in nongestating, ovulating and nonovulating, females. A significant increment in GnRH, P4, and LH was detected in midpregnant vizcachas with respect to early-pregnant and to ovulating females. PR was also significantly increased in midpregnant animals. PR was detected in neurons of the preoptic and hypothalamic areas. Coexistence of both PR and GnRH in neurons of medial preoptic area and supraoptic nucleus was detected. Midpregnant animals showed increased number of PR immunoreactive cells at median eminence, localized adjacently to GnRH immunoreactive fibers. High expression of hypothalamic GnRH and PR, despite an increased level of P4, was correlated with the presence of antral, preovulatory follicles, and luteinized unruptured follicles at midgestation that suggest a possible role of the H-H-G axis in the modulation of ovulation during gestation in L. maximus.

  5. [Patterns of morphological variability in reintroduced populations with two beaver subspecies Castor fiber orientoeuropaeus and Castor fiber belorussicus (Castoridae, Rodentia) as an example].

    PubMed

    Korablev, N P; Korablev, P N

    2012-01-01

    Taking as an example two beaver subspecies (Castor fiber orientoeuropaeus and Castor fiber belorussicus) with documented history of population formation, the patterns of morphological variability in translocated groups of mammals are studied. The variability of quantitative and qualitative traits in the formed populations is not characterized by a single direction. The main trend consists in increasing of adaptive norms diversity as related to body size. There observed a slight increase in the level of fluctuating asymmetry, reduction in polymorphism of nonmetric traits, and increase in fraction of rare aberrations. All these may be caused by inbreeding taking place during the period of prapopulations formation. The results of the study allow for considering the intraspecific differentiation as a consequence of adaptive variability (adaptatiogenesis) or subspecies hybridization. As for stochastic processes (genetic drift, founder effect), they seem to not influence the morphological variability significantly. The differences between discrete and dimensional traits are indicative of population groups' peculiarity.

  6. Characterization of the Kidney Transcriptome of the Long-Haired Mouse Abrothrix hirta (Rodentia, Sigmodontinae) and Comparison with That of the Olive Mouse A. olivacea

    PubMed Central

    Valdez, Lourdes; Giorello, Facundo; Feijoo, Matías; Opazo, Juan C.; Lessa, Enrique P.; Naya, Daniel E.; D’Elía, Guillermo

    2015-01-01

    To understand how small mammals cope with the challenge of water homeostasis is a matter of interest for ecologists and evolutionary biologists. Here we take a step towards the understanding of the transcriptomic functional response of kidney using as a model the long–haired mouse (Abrothrix hirta) a species that distributes across Patagonian steppes and Austral temperate rainforests in Argentina and Chile. Specifically, we i) characterize the renal transcriptome of A. hirta, and ii) compare it with that—already available—of the co-generic and co-distributed A. olivacea. Renal mRNA transcripts from 16 specimens of A. hirta from natural populations were analyzed. Over 500 million Illumina paired-end reads were assembled de novo under two approaches, an individual assembly for each specimen, and a single in-silico normalized joint assembly including all reads from all specimens. The total number of annotated genes was similar with both strategies: an average of 14,956 in individual assemblies and 14,410 in the joint assembly. Overall, 15,463 distinct genes express in the kidney of A. hirta. Transcriptomes of A. hirta and A. olivacea were similar in terms of gene abundance and composition: 95.6% of the genes of A. hirta were also found in A. olivacea making their functional profiles also similar. However, differences in the transcriptome of these two species were observed in the set of highly expressed genes, in terms of private genes for each species and the functional profiles of highly expressed genes. As part of the novel transcriptome characterization, we provide distinct gene lists with their functional annotation that would constitute the basis for further research on these or any other species of the subfamily Sigmodontinae, which includes about 400 living species distributed from Tierra del Fuego to southern United States. PMID:25860131

  7. [Analysis of allozyme variability in populations of three species of brush-haired mice of species Lophuromys (Rodentia, Muridae) from the Bale Mountains National Park in Ethiopia].

    PubMed

    Milishnikov, A N; Lavrenchenko, L A; Aniskin, V M; Varshavskiĭ, A A

    2000-12-01

    Allozyme variability was examined in populations of three endemic species of the species complex Lophuromys flavopunctatus sensu lato: L. chrysopus, L. brevicaudus, and L. melanonyx. These species substitute each other in adjacent latitudinal belts of the Bale Massif in Ethiopia. A deficit of heterozygotes at several loci was found in most samples of all species studied. Moreover, the samples included animals homozygous for two or three minor alleles and heterozygous for alleles that are rare and unique for the given species. It is suggested that the Bale Massif are inhabited by numerous genetically isolated populations of each Lophuromys species, which exchange genes at an extremely low rate. Genotypic disequilibrium observed in most samples is explained by the fact that most sampling localities comprise ranges of two and more micropopulations. In our view, microgeographic subdivision of the populations is caused by recurrent fragmentation of habitats during the Pleistocene glaciation of the Bale Massif and subsequent prolonged isolation of local populations. Gene drift accompanying these processes resulted in high genetic differentiation of the local populations, which probably persisted until the present. Geographical isolation of the Bale Massif, its uniquely diverse ecological conditions, and extraordinary allozyme structure of the Lophuromys populations suggest that these populations represent remnants or direct descendants of relic local populations.

  8. Toxicological Evaluation of Essential Oil From the Leaves of Croton argyrophyllus (Euphorbiaceae) on Aedes aegypti (Diptera: Culicidae) and Mus musculus (Rodentia: Muridae).

    PubMed

    Cruz, R C D; Silva, S L C E; Souza, I A; Gualberto, S A; Carvalho, K S; Santos, F R; Carvalho, M G

    2017-01-27

    Plant-derived essential oils can be used as insecticides for vector control. However, to establish their safety, it is necessary to perform toxicological studies. Herein, we evaluated the chemical composition and insecticidal activity of the essential oil from the leaves of Croton argyrophyllus on the third- and fourth-instar larvae and adult Aedes aegypti (L., 1762). We also evaluated the acute toxicity of the essential oil in adult female Mus musculus The lethal concentration 50 (LC50) and 90 (LC90) of C. argyrophyllus essential oil on larvae of Ae. aegypti were 0.31 and 0.70 mg ml(-1), respectively, and 5.92 and 8.94 mg ml(-1), respectively, on Ae. aegypti adults. The major components of the essential oil were spathulenol (22.80%), (E)-caryophyllene (15.41%), α-pinene (14.07%), and bicyclogermacrene (10.43%). It also displayed acute toxicity in adults of Mus musculus; the intraperitoneal and oral lethal dose 50 (LD50) were 2,000 mg kg(-1) and 2,500 mg kg(-1), respectively. The results showed that the essential oil from C. argyrophyllus leaves has insecticidal activity on Ae. aegypti larvae and adults at an average lethal concentration below the median lethal dose needed to cause acute toxicity in the common mouse.

  9. Musserakis sulawesiensis gen. et sp. n. (Nematoda: Heterakidae) collected from Echiothrix centrosa (Rodentia: Muridae), an old endemic rat of Sulawesi, Indonesia.

    PubMed

    Hasegawa, Hideo; Dewi, Kartika; Asakawa, Mitsuhiko

    2014-11-04

    Musserakis sulawesiensis gen. et sp. n. (Nematoda: Heterakidae) is described from the large-bodied shrew rat, Echiothrix centrosa, one of the old endemic rats of Sulawesi, Indonesia. Musserakis is readily distinguished from other heterakid genera by having non-recurrent and non-anastomosing cephalic cordons, by lacking papillae between papillae groups around precloacal sucker and cloacal aperture and by lacking teeth in the pharyngeal portion. The spicules are equal but with marked dimorphism among individuals. Heterakids collected from other old endemic murids examined, i.e., Crunomys celebensis, Tateomys macrocercus and Tateomys rhinogradoides, and the new endemic rats of Sulawesi, were Heterakis spumosa Schneider, 1866, a cosmopolitan nematode of various murids. It is suggested that M. sulawesiensis is specific to Echiothrix.

  10. Biochronological implications of the Arvicolidae (Rodentia, Mammalia) from the Lower Pleistocene hominid-bearing level of Trinchera Dolina 6 (TD6, Atapuerca, Spain).

    PubMed

    Cuenca-Bescós, G; Laplana, C; Canudo, J I

    1999-01-01

    Level TD6 of the Trinchera Dolina Section in the railway cutting of the Sierre de Atapuerca (Trinchera del Ferrocarril) has yielded a rich small mammal assemblage (26 species) in association with fossil human remains of Homo antecessor. The arvicolids of TD6 are identified as: Mimomys savini, Microtus seseae, Stenocranius gregaloides, Terricola arvalidens, Iberomys huescarensis, Allophaiomys chalinei, and Pliomys episcopalis. The rodent association also includes large rodents (i.e., Castor fiber, Marmota sp., and Hystrix refossa) and the small Allocricetus sp., Eliomys helleri, Micromys minutus, and Apodemus aff. flavicollis. The small vertebrate remains also include Insectivora (Beremendia fissidens, Sorex sp, Neomys sp., Crocidura sp., Galemys sp., Talpa sp., Erinaceus sp.), Chiroptera (Miniopterus schreibersii, Myotis sp., Rhinolophus sp.), and Lagomorpha (Oryctolagus sp., Lepus sp.), as well as lizards, birds and amphibians. The H. antecessor remains are derived from a 15 cm thick layer at the top of TD6 (TD6-T36-43), where A. chalinei, H. refossa and Marmota sp. do not occur. The paleomagnetic Matuyama/Brunhes boundary is found in the overlying level TD7 of the Gran Dolina Section. On the basis of the arvicolids, TD6 can be referred to the Biharian biochron. The Matuyama/Brunhes boundary is fixed in the late Biharian (Microtus-Mimomys rodent Superzone). The species M. savini (without M. pusillus), as well as the evolutionary stage of Microtus s.l., are characteristic of the Late Biharian. The evolutionary level of the species M. savini, T. arvalidens, S. gregaloides indicates that TD6 is older than West Runton (type Cromerian). In the Trinchera Dolina Section we are able to calibrate, for the first time, the evolutionary level of important biochronological markers with magnetostratigraphy. We propose that a radiation of Microtus s.l., along with the first appearance of primitive S. gregaloides, T. arvalidens and Iberomys, took place just before the Matuyama/Brunhes boundary. These species can be considered as characteristic elements of early Pleistocene faunas.

  11. A new species of the genus Demodex Owen, 1843 (Acari: Demodecidae) from the ear canals of the house mouse Mus musculus L. (Rodentia: Muridae).

    PubMed

    Izdebska, Joanna N; Rolbiecki, Leszek

    2015-06-01

    A new species Demodex conicus n. sp. is described based on adult and juvenile stages from the ear canals of the house mouse Mus musculus L. in Poland. The new species is most similar to D. auricularis Izdebska, Rolbiecki & Fryderyk, 2014 from the ear canals of the wood mouse Apodemus sylvaticus (L.), but differs in the following features: the gnathosoma is triangular, the supracoxal spines (setae elc.p) are conical, the spines on the terminal segment of palp are four, the striation on opisthosoma is fine but dense, the vulva is located at a distance of c.17 µm from posterior level of legs IV, and the male genital opening is located at the level of legs I. The differences also relate to body size and proportions, female D. conicus n. sp. being, on average slightly larger, and male significantly larger than D. auricularis. Males of the new species also have longer and more massive opisthosoma than males of D. auricularis. Demodex conicus n. sp. was found in 17.5% of the mice studied from different locations in Poland.

  12. Evolution of the structure and composition of house mouse satellite DNA sequences in the subgenus Mus (Rodentia: Muridea): a cytogenomic approach.

    PubMed

    Cazaux, B; Catalan, J; Justy, F; Escudé, C; Desmarais, E; Britton-Davidian, J

    2013-06-01

    The composition and orientation of the house mouse satellite DNA sequences (minor, major, TLC) were investigated by a FISH and CO-FISH approach in 11 taxa belonging to three clades of the subgenus Mus. Using a phylogenetic framework, our results highlighted two distribution patterns. The TLC satellite, the most recently discovered satellite, was present in all clades but varied quantitatively among species. This distribution supported its appearance in the ancestor of the subgenus followed by independent evolution in species of each clade. In contrast, the minor and major satellites occurred in only two clades of the subgenus indicating the simultaneous and recent amplification of these sequences. In addition, although qualitative differences in the composition and orientation of the satellite sequences were observed among the taxa, none of the features studied were unique to the house mouse and could account for the extensive chromosomal plasticity evidenced in Mus musculus domesticus.

  13. The sympatric occurrence of two genetically divergent lineages of sucking louse, Polyplax arvicanthis (Phthiraptera: Anoplura), on the four-striped mouse genus, Rhabdomys (Rodentia: Muridae).

    PubMed

    du Toit, Nina; Matthee, Sonja; Matthee, Conrad A

    2013-04-01

    Within southern Africa, the widely distributed four-striped mouse genus (Rhabdomys) is parasitized by, amongst others, the specific ectoparasitic sucking louse, Polyplax arvicanthis. Given the presence of significant geographically structured genetic divergence in Rhabdomys, and the propensity of parasites to harbour cryptic diversity, the molecular systematics of P. arvicanthis was investigated. Representatives of P. arvicanthis were sampled from Rhabdomys at 16 localities throughout southern Africa. Parsimony and Bayesian gene trees were constructed for the mitochondrial COI, 12S rRNA, 16S rRNA and nuclear CAD genes. Our findings support the existence of 2 genetic groups within P. arvicanthis separated by at least 25% COI sequence divergence, which is comparable to that observed among recognized Polyplax species. We therefore propose that these 2 genetic lineages probably represent distinct species and that the apparent absence of clear morphological differences may point to cryptic speciation. The 2 taxa have sympatric distributions throughout most of the sampled host range and also occasionally occur sympatrically on the same host individual. The co-occurrence of these genetically distinct lineages probably resulted from parasite duplication via host-associated allopatric divergence and subsequent reciprocal range expansions of the 2 parasite taxa throughout southern Africa.

  14. The impact of gape on the performance of the skull in chisel-tooth digging and scratch digging mole-rats (Rodentia: Bathyergidae)

    NASA Astrophysics Data System (ADS)

    McIntosh, Andrew F.; Cox, Philip G.

    2016-10-01

    The African mole-rats (Bathyergidae) are a family of rodents highly adapted for life underground. Previous research has shown that chisel-tooth digging mole-rats (which use their incisors to dig burrows) are clearly distinguishable from scratch diggers (which only use the forelimbs to tunnel) on the basis of morphology of the skull, and that the differences are linked to the production of high bite forces and wide gapes. We hypothesized that the skull of a chisel-tooth digging mole-rat would perform better at wider gapes than that of a scratch digging mole-rat during incisor biting. To test this hypothesis, we created finite-element models of the cranium of the scratch digging Bathyergus suillus and the chisel-tooth digging Fukomys mechowii, and loaded them to simulate incisor bites at different gapes. Muscle loads were scaled such that the ratio of force to surface area was the same in both models. We measured three performance variables: overall stress across the cranium, mechanical efficiency of biting and degree of deformation across the skull. The Fukomys model had a more efficient incisor bite at all gapes, despite having greater average stress across the skull. In addition, the Fukomys model deformed less at wider gapes, whereas the Bathyergus model deformed less at narrower gapes. These properties of the cranial morphology of Fukomys and Bathyergus are congruent with their respective chisel-tooth and scratch digging behaviours and, all other factors being equal, would enable the more efficient production of bite force at wider gapes in Fukomys. However, in vivo measurements of muscle forces and activation patterns are needed to fully understand the complex biomechanics of tooth digging.

  15. The role of chromosomal rearrangements and geographical barriers in the divergence of lineages in a South American subterranean rodent (Rodentia: Ctenomyidae: Ctenomys minutus)

    PubMed Central

    Lopes, C M; Ximenes, S S F; Gava, A; de Freitas, T R O

    2013-01-01

    Identifying factors and the extent of their roles in the differentiation of populations is of great importance for understanding the evolutionary process in which a species is involved. Ctenomys minutus is a highly karyotype–polymorphic subterranean rodent, with diploid numbers ranging from 42 to 50 and autosomal arm numbers (ANs) ranging from 68 to 80, comprising a total of 45 karyotypes described so far. This species inhabits the southern Brazilian coastal plain, which has a complex geological history, with several potential geographical barriers acting on different time scales. We assessed the geographical genetic structure of C. minutus, examining 340 individuals over the entire distributional range and using information from chromosomal rearrangements, mitochondrial DNA (mtDNA) sequences and 14 microsatellite loci. The mtDNA results revealed seven main haplogroups, with the most recent common ancestors dating from the Pleistocene, whereas clustering methods defined 12 populations. Some boundaries of mtDNA haplogroups and population clusters can be associated with potential geographical barriers to gene flow. The isolation-by-distance pattern also has an important role in fine-scale genetic differentiation, which is strengthened by the narrowness of the coastal plain and by common features of subterranean rodents (that is, small fragmented populations and low dispersal rates), which limit gene flow among populations. A step-by-step mechanism of chromosomal evolution can be suggested for this species, mainly associated with the metapopulation structure, genetic drift and the geographical features of the southern Brazilian coastal plain. However, chromosomal variations have no or very little role in the diversification of C. minutus populations. PMID:23759727

  16. Causes and consequences of change rates in the habitat of the threatened tropical porcupine, Sphiggurus mexicanus (Rodentia: Erethizontidae) in Oaxaca, Mexico: implications for its conservation.

    PubMed

    Lorenzo, Consuelo; Sántiz, Eugenia C; Navarrete, Darío A; Bolaños, Jorge

    2014-12-01

    Land use changes by human activities have been the main causes of habitats and wildlife population degradation. In the Tehuantepec Isthmus in Oaxaca, the tropical habitat of the porcupine Sphiggurus mexicanus has been subject to vegetation and land use changes, causing its reduction and fragmentation. In this study, we estimated vegetation cover and land use (δn) change rates and assessed habitat availability and potential cor- ridors for possible porcupine movements to avoid its isolation. In the study area, the type of vegetation with the most change rate value was the savanna (δn = -2.9), transformed into induced grasslands. Additionally, we have observed the porcupine (since 2011) in semi-deciduous (δn = -0.87) and tropical dry (δn = -0.89) forests that have been transformed in temporal agriculture and mesquite and induced grasslands. The vegetation inhabited by the porcupine resulted in recording a total of 64 plant species (44 trees, nine vines, seven herbs, four shrubs), of which the vine Bunchosia lanceolata showed the highest importance value (41.85) followed by the trees Guazuma ulmifolia (22.71), Dalbergia glabra (18.05), and Enterolobium cyclocarpum (17.02). The habitat evaluation and potential corridor analysis showed that only 1 501.93ha could be considered as suitable habitats with optimum structural conditions (coverage, surface, and distances to transformed areas) to maintain viable populations of S. mexicanus, and 293.6 ha as corridors. An increasing destruction of the porcupines' habitat has been observed in the study area due to excessive logging, and actions for this species and its habitat conserva- tion and management have to be taken urgently.

  17. Phylogeographic structure in long-tailed voles (Rodentia: Arvicolinae) belies the complex Pleistocene history of isolation, divergence, and recolonization of Northwest North America's fauna.

    PubMed

    Sawyer, Yadéeh E; Cook, Joseph A

    2016-09-01

    Quaternary climate fluctuations restructured biodiversity across North American high latitudes through repeated episodes of range contraction, population isolation and divergence, and subsequent expansion. Identifying how species responded to changing environmental conditions not only allows us to explore the mode and tempo of evolution in northern taxa, but also provides a basis for forecasting future biotic response across the highly variable topography of western North America. Using a multilocus approach under a Bayesian coalescent framework, we investigated the phylogeography of a wide-ranging mammal, the long-tailed vole, Microtus longicaudus. We focused on populations along the North Pacific Coast to refine our understanding of diversification by exploring the potentially compounding roles of multiple glacial refugia and more recent fragmentation of an extensive coastal archipelago. Through a combination of genetic data and species distribution models (SDMs), we found that historical climate variability influenced contemporary genetic structure, with multiple isolated locations of persistence (refugia) producing multiple divergent lineages (Beringian or northern, southeast Alaska or coastal, and southern or continental) during glacial advances. These vole lineages all occur along the North Pacific Coast where the confluence of numerous independent lineages in other species has produced overlapping zones of secondary contact, collectively a suture zone. Finally, we detected high levels of neoendemism due to complex island geography that developed in the last 10,000 years with the rising sea levels of the Holocene.

  18. Similarities and differences among the chromosomes of the wild guinea pig Cavia tschudii and the domestic guinea pig Cavia porcellus (Rodentia, Caviidae)

    PubMed Central

    Walker, Laura I.; Soto, Miguel A.; Spotorno, Ángel E.

    2014-01-01

    Abstract Cavia tschudii Fitzinger, 1867 is a wild guinea pig species living in South America that according to the analysis of mitochondrial genes is the closest wild form of the domestic guinea pig. To investigate the genetic divergence between the wild and domestic species of guinea pigs from a cytogenetic perspective, we characterized and compared the C, G and AgNOR banded karyotypes of molecularly identified Cavia tschudii and Cavia porcellus Linnaeus, 1758 specimens for the first time. Both species showed 64 chromosomes of similar morphology, although C. tschudii had four medium size submetacentric pairs that were not observed in the C. porcellus karyotype. Differences in the C bands size and the mean number of AgNOR bands between the karyotypes of the two species were detected. Most of the two species chromosomes showed total G band correspondence, suggesting that they probably represent large syntenic blocks conserved over time. Partial G band correspondence detected among the four submetacentric chromosomes present only in the C. tschudii karyotype and their subtelocentric homologues in C. porcellus may be explained by the occurrence of four pericentric inversions that probably emerged and were fixed in the C. tschudii populations under domestication. The role of the chromosomal and genomic differences in the divergence of these two Cavia species is discussed. PMID:25147626

  19. Two New Species of Demodex (Acari: Demodecidae) with a Redescription of Demodex musculi and Data on Parasitism in Mus musculus (Rodentia: Muridae).

    PubMed

    Izdebska, Joanna N; Rolbiecki, Leszek

    2015-07-01

    This article describes two new skin mite species found on the house mouse Mus musculus L., 1758. Demodex marculus sp. nov. is a very small demodecid mite (adult stages, on average, 99 µm in length) found in mouse skin in the abdomen, back, limbs, and anal area. It is characterized by relatively large bossing hammer-shaped supracoxal spines, embedded in the trapezoidal gnathosoma. Demodex fusiformis sp. nov., in turn, is a little larger (adult stages on average 111 µm in length), with a small oval gnathosoma equipped with fine, knob-like supracoxal spines. It was found in the skin of abdomen, back, and limbs. Moreover, Demodex musculi (Oudemans, 1897) was redescribed, which is small demodecid mite (adult stages on average 142 µm in length) and characterized by relatively large morphological variation and considerable sexual dimorphism. The characteristic feature of this species is the strongly elongated and rectangular gnathosoma equipped with very large wedge-shaped supracoxal spines. D. musculi was found in the skin of various, haired regions of the mice body (head, neck, abdomen, back, limbs, genital-anal region, and tail). Moreover, one more demodecid mite was found in the skin of the examined mice, it was Demodex flagellurus Bukva, 1985, which was found only in the genital area. Overall infection of Mus musculus L. by all species of Demodex was with the prevalence of 100%, mean intensity of 24.0, and range of intensity of 1-109. Despite high infection levels, no symptoms of parasitosis were observed in the hosts.

  20. A new species of Demodex (Acari: Demodecidae) with data on topical specificity and topography of demodectic mites in the striped field mouse Apodemus agrarius (Rodentia: Muridae).

    PubMed

    Izdebska, Joanna N; Rolbiecki, Leszek

    2013-11-01

    This article describes morphological characteristics and the occurrence of Demodex gracilentus sp. nov., which was found in the striped field mouse Apodemus agrarius (Pallas, 1771) in the skin of vibrissae area. D. gracilentus occurred in 36.7% of the rodents examined. D. gracilentus is a relatively large representative of the genus (adult stages on average 292 microm in length), a slender, elongated body; characteristic feature of these mites are conical supracoxal spines on dorsal side of gnathosoma, palps with asymmetric, forked triple spines on palptarsus, and the presence of rhomboidal opisthosomal organ. So far, the occurrence of three specific representatives of the family Demodecidae has been demonstrated in A. agrarius: Demodex apodemi (Hirst, 1918) (= Demodex arvicolae apodemi Hirst, 1918), Demodex agrarii Bukva, 1994, and Demodex huttereri Mertens, Lukoschus et Nutting, 1983. The first one is related to common hair follicles, especially in the skin of the head, while the next one inhabits the external auditory meatus, and the last one occurs in the meibomian glands of the eyelids.

  1. Development of nine new microsatellite loci for the American beaver, Castor canadensis (Rodentia: Castoridae), and cross-species amplification in the European beaver, Castor fiber

    USGS Publications Warehouse

    Pelz-Serrano, K.; Munguia-Vega, A.; Piaggio, A.J.; Neubaum, M.; Munclinger, P.; PArtl, A.; van Riper, Charles; Culver, M.

    2009-01-01

    We developed nine new nuclear dinucleotide microsatellite loci for Castor canadensis. All loci were polymorphic, except for one. The number of alleles ranged from two to four and from five to 12 in populations from Arizona and Wisconsin, respectively. Average heterozygosity ranged from 0.13 to 0.86 per locus. Since cross-species amplification in Castor fiber was successful only in four loci, we tested also nine recently published C. canadensis loci in the Eurasian species. Eight of the published loci amplified; however, three were monomorphic. The number of alleles was lower in C. fiber than in C. canadensis at all loci tested. ?? 2009 Blackwell Publishing Ltd.

  2. [Spatial distribution of Marmota baibacina and M. sibirica (Marmota, Sciuridae, Rodentia) in a zone of sympatry in Mongolian Altai: bioacoustic analysis].

    PubMed

    Brandler, O V; Nikol'skiĭ, A A; Kolesnikov, V V

    2010-01-01

    The spatial distribution of two marmot species Marmota baibacina and M. sibirica in a zone of coexistence was studied by using their alarm call as a diagnostic trait. It was found that M. baibacina prefers to inhabit bouldery screes, whereas M. sibirica inhabits all suitable biotopes. The difference in biotopic distribution of these species could be explained by M. sibirica forcing M. baibacina out of optimum habitats. Cases of coexistence of both species in one family group sites were registered, which might contribute to the appearance of hybrids.

  3. Trichospirura aethiopica n. sp. (Nematoda: Rhabdochonidae) from Malacomys longipes (Rodentia: Muridae) in Gabon, first record of the genus in the Ethiopian Realm

    PubMed Central

    Bain, Odile; Junker, Kerstin

    2013-01-01

    Trichospirura aethiopica n. sp. is described from unidentified tubular structures (pancreatic ducts?) near the stomach of the murid Malacomys longipes Milne-Edwards, 1877 in Gabon. The extremely long and narrow buccal capsule, posterior position of the vulva, unequal spicules and absence of caudal alae readily identified the specimens as belonging to Trichospirura Smith & Chitwood, 1967, but a combination of several characters distinguished them from the described species in this genus. Males of the new species are characterized by the absence of precloacal papillae, the presence of four pairs of postcloacal papillae and a left spicule length of 165–200 μm. With only five nominal and one unnamed species, the host range of Trichospirura extends into the Neotropical, Indo-Malayan and Ethiopian Realms and comprises three classes of vertebrates, Amphibia, Reptilia and Mammalia, suggesting a larger species diversity than that currently recorded. Detection is difficult as predilection sites are often outside the gut lumen. It was noted that, irrespective of their geographic origin, species from mammals share certain characters (shorter left spicule and absence of precloacal papillae) that oppose them to those from amphibians and reptiles. A hypothesis for the origin of Trichospirura in mammals through a remote host-switching event in tupaiids in southern Asia, likely facilitated by the intermediate hosts, and for their subsequent migration to the Ethiopian and finally Neotropical Realm is proposed. Regarding the two species from anurans and saurians in the Antilles, one or two host-switching events are considered equally possible, based on morphological characters. PMID:23369432

  4. The gastrointestinal helminths of Lorentzimys nouhuysi (Rodentia: Muridae) with descriptions of two new genera and three new species (Nematoda) from Papua New Guinea.

    PubMed

    Smales, L R

    2010-06-01

    Helminths, 3 cestode and 8 nematode species, including 2 new genera, 5 new species, and 1 putative new species, of nematode were collected from the digestive tracts of 23 Lorentzimys nouhuysi (Murinae; Hydromyini) from Papua New Guinea. Odilia wauensis n. sp. (Heligmonellidae) most closely resembles Odilia mallomyos Hasegawa and Syafruddin, 1994, but differs from this species in the detail of the synlophe ridges, the length and tip shape of the spicules, the absence of a gubernaculum, and the size of the eggs. Papuastrongylus kishinamiae n. gen., n. sp. differs from all other genera in the Herpetostrongylidae in the form of the synlophe and spicules, the lack of a gubernaculum, and in being monodelphic. Syphacia lorentzimyos n. sp. and Syphacia mamelonitenuis n. sp. (Oxyuridae) differ from all other species in having a circular cephalic plate and from each other in that S. mamelonitenuis lacks lateral alae. Lorentzicola woolleyae n. gen., n. sp. differs from all other genera in the Oxyuridae (Syphaciini) in having the peribuccal wall with denticles, a simple esophagus, and males with 3 mamelons of the Syphacia type. The helminth assemblage of L. nouhuysi did not resemble that of any other hydromyin rodent from the region studied thus far.

  5. MtDNA CytB Structure of Rhombomys opimus (Rodentia: Gerbellidae), the Main Reservoir of Cutaneous Leishmaniasis in the Borderline of Iran-Turkmenistan

    PubMed Central

    Bakhshi, Hasan; Oshaghi, Mohammad Ali; Abai, Mohammad Reza; Rassi, Yavar; Akhavan, Amir Ahmad; Mohebali, Mehdi; Hajaran, Homa; Mohtarami, Fatemeh; Mirzajani, Hossein; Maleki-Ravasan, Naseh

    2013-01-01

    Background: Great gerbils, Rhombomys opimus, are the main reservoir host of zoonootic cutaneous leishmaniasis (ZCL) in Iran and neighboring countries. Based on morphological traits two subspecies R. opimus sodalis and R. opimus sargadensis have reported in the country. However, variation in infection rate and signs to Leishmania parasites, phenotype, size, and sexual polymorphisms demand more details to elucidate clearly the role of great gerbils in ZCL epidemiology. Methods: PCR-RFLP and PCR-direct sequencing were used to analyze mitochondrial DNA cytochrome B (mtDNA-cytB) gene structure of R. opimus collected from Golestan and Khorasan-e-Razavi Provinces in 2011 that are neighbor to Turkmenistan Country where ZCL is endemic in both sides of the borderline. Results: All of the specimens (n= 61) were morphologically or genetically similar to the typical R. opimus sodalis. However, there were 9 (1.5%) DNA substitutions throughout the 583 bp of the Cyt b gene of the samples sequenced comprising six DNA haplotypes. Maximum likelihood or neighbor joining phylogenetic trees inferred from the sequences could resolve the populations according to their subspecies as well as geographical origins. Discussion: The DNA polymorphisms in the great gerbils may correspond to the signs and infection rate in the animal. However, further studies are needed to match these six haplotypes with different signs and parasite sustaining following infection with L. major in the great gerbils. PMID:24409443

  6. Lineage-specific responses of tooth shape in murine rodents (murinae, rodentia) to late Miocene dietary change in the Siwaliks of Pakistan.

    PubMed

    Kimura, Yuri; Jacobs, Louis L; Flynn, Lawrence J

    2013-01-01

    Past ecological responses of mammals to climate change are recognized in the fossil record by adaptive significance of morphological variations. To understand the role of dietary behavior on functional adaptations of dental morphology in rodent evolution, we examine evolutionary change of tooth shape in late Miocene Siwalik murine rodents, which experienced a dietary shift toward C4 diets during late Miocene ecological change indicated by carbon isotopic evidence. Geometric morphometric analysis in the outline of upper first molars captures dichotomous lineages of Siwalik murines, in agreement with phylogenetic hypotheses of previous studies (two distinct clades: the Karnimata and Progonomys clades), and indicates lineage-specific functional responses to mechanical properties of their diets. Tooth shapes of the two clades are similar at their sympatric origin but deviate from each other with decreasing overlap through time. Shape change in the Karnimata clade is associated with greater efficiency of propalinal chewing for tough diets than in the Progonomys clade. Larger body mass in Karnimata may be related to exploitation of lower-quality food items, such as grasses, than in smaller-bodied Progonomys. The functional and ecophysiological aspects of Karnimata exploiting C4 grasses are concordant with their isotopic dietary preference relative to Progonomys. Lineage-specific selection was differentially greater in Karnimata, and a faster rate of shape change toward derived Karnimata facilitated inclusion of C4 grasses in the diet. Sympatric speciation in these clades is most plausibly explained by interspecific competition on resource utilization between the two, based on comparisons of our results with the carbon isotope data. Interspecific competition with Karnimata may have suppressed morphological innovation of the Progonomys clade. Pairwise analyses of morphological and carbon isotope data can uncover ecological causes of sympatric speciation and define functional adaptations of teeth to resources.

  7. Panic-like defensive behavior but not fear-induced antinociception is differently organized by dorsomedial and posterior hypothalamic nuclei of Rattus norvegicus (Rodentia, Muridae).

    PubMed

    Biagioni, A F; Silva, J A; Coimbra, N C

    2012-04-01

    The hypothalamus is a forebrain structure critically involved in the organization of defensive responses to aversive stimuli. Gamma-aminobutyric acid (GABA)ergic dysfunction in dorsomedial and posterior hypothalamic nuclei is implicated in the origin of panic-like defensive behavior, as well as in pain modulation. The present study was conducted to test the difference between these two hypothalamic nuclei regarding defensive and antinociceptive mechanisms. Thus, the GABA(A) antagonist bicuculline (40 ng/0.2 µL) or saline (0.9% NaCl) was microinjected into the dorsomedial or posterior hypothalamus in independent groups. Innate fear-induced responses characterized by defensive attention, defensive immobility and elaborate escape behavior were evoked by hypothalamic blockade of GABA(A) receptors. Fear-induced defensive behavior organized by the posterior hypothalamus was more intense than that organized by dorsomedial hypothalamic nuclei. Escape behavior elicited by GABA(A) receptor blockade in both the dorsomedial and posterior hypothalamus was followed by an increase in nociceptive threshold. Interestingly, there was no difference in the intensity or in the duration of fear-induced antinociception shown by each hypothalamic division presently investigated. The present study showed that GABAergic dysfunction in nuclei of both the dorsomedial and posterior hypothalamus elicit panic attack-like defensive responses followed by fear-induced antinociception, although the innate fear-induced behavior originates differently in the posterior hypothalamus in comparison to the activity of medial hypothalamic subdivisions.

  8. Proechimys (Rodentia, Echimyidae): characterization and taxonomic considerations of a form with a very low diploid number and a multiple sex chromosome system

    PubMed Central

    2013-01-01

    Background Proechimys is the most diverse genus in family Echimyidae, comprising 25 species (two of which are polytypic) and 39 taxa. Despite the numerous forms of this rodent and their abundance in nature, there are many taxonomic problems due to phenotypic similarities within the genus and high intraspecific variation. Extensive karyotypic variation has been noted, however, with diploid numbers (2n) ranging from 14 to 62 chromosomes. Some heteromorphism can be found, and 57 different karyotypes have been described to date. Results In the present work, we describe a cytotype with a very low 2n. Specimens of Proechimys cf. longicaudatus were collected from two different places in northern Mato Grosso state, Brazil (12°54″S, 52°22″W and 9°51′17″S, 58°14′53″W). The females and males had 16 and 17 chromosomes, respectively; all chromosomes were acrocentric, with the exception of the X chromosome, which was bi-armed. The sex chromosome system was found to be XY1Y2, originating from a Robertsonian rearrangement involving the X and a large acrocentric autosome. Females had two Neo-X chromosomes, and males had one Neo-X and two Y chromosomes. NOR staining was found in the interstitial region of one autosomal pair. Conclusions Comparison of this karyotype with those described in the literature revealed that Proechimys with similar karyotypes had previously been collected from nearby localities. We therefore suggest that this Proechimys belongs to a different taxon, and is either a new species or one that requires reassessment. PMID:23496787

  9. The New World filarial genus Molinema Freitas & Lent, 1939 (Nematoda: Onchocercidae), with a description of four new species parasitic in the Echimyidae (Rodentia).

    PubMed

    Guerrero, R; Bain, O

    2001-03-01

    Four new species of Molinema (Filarioidea: Onchocercidae), parasites of echimyid rodents in South America, are described: M. algardneri n. sp. from Proechimys amphichoricus, M. barbarae n. sp. from P. cayennensis, both in Venezuela (Rio Negro and Cerro La Neblina, respectively), M. peruviensis n. sp. from P. steerei in Peru (lower Urubamba), and M. nattereri n. sp. (= Filaria diacantha Molin, 1858 pro parte) from Echimys ? didelphoides (= Loncheres rufa) in Brazil (Matto Grosso). They differ from each other and from the previously described species in the following characters: flat or concave head, cephalic ratio (distance between cephalic papillae in median view/lateral view), size and shape of the buccal capsule, length of the oesophagus, cuticular ornamentation of the female body, length of the ovijector, thick or slim female tail, area rugosa, long or short filament in the left spicule, heel in the right spicule, respective position of postcloacal papilla pairs 5 and 6, shape of the caudal lappets, terminal point present or absent, and the microfilariae. Molinema, which belongs to the worldwide Dipetalonema line, is distributed in two of the ten families of the Caviomorpha (South American Hystrichognathi have extended their distribution in South America since the early Oligocene). Nine species are parasitic in the Echimyidae (suborder Caviida); they have a short oesophagus and a complete or reduced set of precloacal papillae (four or three pairs). Two species are parasitic in the Erethizontidae (Erethizontida) and might be more primitive in having a well-developed oesophagus. However, the type-species M. diacantha, of which a female specimen was studied, has a large buccal capsule and has evolved concave head, while M. arbuta has a reduced buccal capsule and primitive flat head. This last species is a parasite of a Nearctic porcupine and probably represents a small line of Molinema which migrated to the north with its hosts when communications were established between the two American continents 3 mya (Pleistocene). M. sprenti, the unique parasite of the Castoridae in North America, is considered to be derived from this group by capture.

  10. Characterization of the kidney transcriptome of the long-haired mouse Abrothrix hirta (Rodentia, Sigmodontinae) and comparison with that of the olive mouse A. olivacea.

    PubMed

    Valdez, Lourdes; Giorello, Facundo; Feijoo, Matías; Opazo, Juan C; Lessa, Enrique P; Naya, Daniel E; D'Elía, Guillermo

    2015-01-01

    To understand how small mammals cope with the challenge of water homeostasis is a matter of interest for ecologists and evolutionary biologists. Here we take a step towards the understanding of the transcriptomic functional response of kidney using as a model the long-haired mouse (Abrothrix hirta) a species that distributes across Patagonian steppes and Austral temperate rainforests in Argentina and Chile. Specifically, we i) characterize the renal transcriptome of A. hirta, and ii) compare it with that-already available-of the co-generic and co-distributed A. olivacea. Renal mRNA transcripts from 16 specimens of A. hirta from natural populations were analyzed. Over 500 million Illumina paired-end reads were assembled de novo under two approaches, an individual assembly for each specimen, and a single in-silico normalized joint assembly including all reads from all specimens. The total number of annotated genes was similar with both strategies: an average of 14,956 in individual assemblies and 14,410 in the joint assembly. Overall, 15,463 distinct genes express in the kidney of A. hirta. Transcriptomes of A. hirta and A. olivacea were similar in terms of gene abundance and composition: 95.6% of the genes of A. hirta were also found in A. olivacea making their functional profiles also similar. However, differences in the transcriptome of these two species were observed in the set of highly expressed genes, in terms of private genes for each species and the functional profiles of highly expressed genes. As part of the novel transcriptome characterization, we provide distinct gene lists with their functional annotation that would constitute the basis for further research on these or any other species of the subfamily Sigmodontinae, which includes about 400 living species distributed from Tierra del Fuego to southern United States.

  11. Intense genomic reorganization in the genus Oecomys (Rodentia, Sigmodontinae): comparison between DNA barcoding and mapping of repetitive elements in three species of the Brazilian Amazon

    PubMed Central

    Gomes Júnior, Renan Gabriel; Schneider, Carlos Henrique; de Lira, Thatianna; Carvalho, Natália Dayane Moura; Feldberg, Eliana; da Silva, Maria Nazareth Ferreira; Gross, Maria Claudia

    2016-01-01

    Abstract Oecomys Thomas, 1906 is one of the most diverse and widely distributed genera within the tribe Oryzomyini. At least sixteen species in this genus have been described to date, but it is believed this genus contains undescribed species. Morphological, molecular and cytogenetic study has revealed an uncertain taxonomic status for several Oecomys species, suggesting the presence of a complex of species. The present work had the goal of contributing to the genetic characterization of the genus Oecomys in the Brazilian Amazon. Thirty specimens were collected from four locations in the Brazilian Amazon and three nominal species recognized: Oecomys auyantepui (Tate, 1939), Oecomys bicolor (Tomes, 1860) and Oecomys rutilus (Anthony, 1921). COI sequence analysis grouped Oecomys auyantepui, Oecomys bicolor and Oecomys rutilus specimens into one, three and two clades, respectively, which is consistent with their geographic distribution. Cytogenetic data for Oecomys auyantepui revealed the sympatric occurrence of two different diploid numbers, 2n=64/NFa=110 and 2n=66/NFa=114, suggesting polymorphism while Oecomys bicolor exhibited 2n=80/NFa=142 and Oecomys rutilus 2n=54/NFa=90. The distribution of constitutive heterochromatin followed a species-specific pattern. Interspecific variation was evident in the chromosomal location and number of 18S rDNA loci. However, not all loci showed signs of activity. All three species displayed a similar pattern for 5S rDNA, with only one pair carrying this locus. Interstitial telomeric sites were found only in Oecomys auyantepui. The data presented in this work reinforce intra- and interspecific variations observed in the diploid number of Oecomys species and indicate that chromosomal rearrangements have led to the appearance of different diploid numbers and karyotypic formulas. PMID:27830049

  12. Host location, survival and fecundity of the Oriental rat flea Xenopsylla cheopis (Siphonaptera: Pulicidae) in relation to black rat Rattus rattus (Rodentia: Muridae) host age and sex.

    PubMed

    Mears, S; Clark, F; Greenwood, M; Larsen, K S

    2002-10-01

    Host choice and fecundity are two factors that may contribute to the variation in flea counts observed when assessing the potential risk of flea-borne transmission of pathogens from rodents to humans. Using the black rat, Rattus rattus Linnaeus, as host the effects of age and sex on host choice and fecundity of the Oriental rat flea, Xenopsylla cheopis Rothschild, were examined experimentally at 25 degrees C and 80% rh. During the first two days of emergence from cocoons, female fleas dominated the sex ratio by 4:1 but from the third day onwards this switched to a male-dominated sex ratio of 4:1. The sex of the flea did not influence their host-seeking behaviour. Newly emerged fleas of both sexes were not influenced by the rat's presence and at seven days old both sexes demonstrated similar levels of attraction toward the rat host. The sex of the rat did not affect flea host-seeking behaviour. There was a 50-70% decline in the initial number of adult fleas during the first week after their release onto a rat host, and this decline was greatest on juvenile rats. Flea fecundity was also significantly lower on juvenile rat hosts but no differences due to the sex of the rat were observed. This experimental study supports the hypothesis that differences in flea count due to host sex, reported in field surveys, result from sexual differences in host behaviour and not from discriminatory host-seeking behaviour by X. cheopis. Differences in flea count due to host age may be affected by differences in X. cheopis fecundity, which may itself be mediated by host behaviour such as grooming.

  13. Postnatal allometry of the skeleton in Tupaia glis (Scandentia: Tupaiidae) and Galea musteloides (Rodentia: Caviidae)--a test of the three-segment limb hypothesis.

    PubMed

    Schilling, Nadja; Petrovitch, Alexander

    2006-01-01

    During the evolution of therian mammals, the two-segmented, sprawled tetrapod limbs were transformed into three-segmented limbs in parasagittal zig-zag configuration (three-segment limb hypothesis). As a consequence, the functional correspondence of limb segments has changed (now: scapula to thigh, upper arm to shank, fore arm plus hand to foot). Therefore, the scapula was taken into account in the current study of the postnatal growth of the postcranial skeleton in two small mammalian species (Tupaia glis, Galea musteloides). Comparisons were made between the functionally equivalent elements and not in the traditional way between serially homologous segments. This study presents a test of the three-segment limb hypothesis which predicts a greater ontogenetic congruence in the functionally equivalent elements in fore and hind limbs than in the serially homologous elements. A growth sequence, with decreasing regression coefficients from proximal to distal, was observed in both species under study. This proximo-distal growth sequence is assumed to be ancestral in the ontogeny of eutherian mammals. Different reproductive modes have evolved within eutherian mammals. To test the influence of different life histories on ontogenetic scaling during postnatal growth, one species with altricial juveniles (Tupaia glis) assumed to be the ancestral mode of development for eutherians and one species with derived, precocial young (Galea musteloides) were selected. The growth series covered postnatal development from the first successive steps with a lifted belly to the adult locomotory pattern; thus, functionally equivalent developmental stages were compared. The higher number of allometrically positive or isometrically growing segments in the altricial mammalian species was interpreted as a remnant of the fast growth period in the nest without great locomotor demands, and the clearly negative allometry in nearly all segments in the precocial young was interpreted as a response to the demand on early locomotor activity. Different life histories seem to have a strong influence on postnatal ontogenetic scaling; the effects of the developmental differences are still observable when comparing adults of the two species.

  14. Laboratory evaluation of fipronil and imidacloprid topical insecticides for control of the plague vector Oropsylla montana (Siphonaptera: Ceratophyllidae) on california ground squirrels (Rodentia: Sciuridae).

    PubMed

    Metzger, Marco E; Rust, Michael K

    2002-01-01

    Two insecticides, fipronil and imidacloprid, were evaluated for efficacy and longevity against Oropsylla montana (Baker), the most important vector of plague in California. Wild-caught California ground squirrels, Spermophilus beecheyi (Richardson), were individually housed in the laboratory to serve as natural hosts to O. montana and for on-animal insecticide trials. Several concentrations oftechnical grade fipronil and imidacloprid in acetone were applied to samples of clean rodent bedding to determine residual activity and longevity against fleas. Immature and adult cat fleas, Ctenocephalides felis (Bouche), were used as representative fleas for periodic assays in place of less fecund O. montana. Toxicity of treated bedding did not decrease significantly for 1 yr at all applied concentrations. Fipronil provided 100% kill for at least 1 yr at > or = 100 ppm, whereas imidacloprid required 10,000 ppm for similar performance. Laboratory squirrels were treated with topical formulations of fipronil (Frontline Top Spot) and imidacloprid (Advantage Flea Adulticide) at a dosage rate of 15 mg/kg and evaluated for residual activity every 2 wk against adult O. montana. Residual activity was determined by percent recovery of O. montana adults released on treated and untreated animals after 48 h. Frontline provided 100% kill of adult fleas for at least 10 wk, and up to 26 wk on one animal. Advantage failed to provide 100% kill of adult fleas at 2 wk, with complete loss of efficacy by week 6. Concurrent assays with bedding samples from squirrel nest boxes showed negligible toxicity transfer from treated animals to nest bedding.

  15. Bioregion heterogeneity correlates with extensive mitochondrial DNA diversity in the Namaqua rock mouse, Micaelamys namaquensis (Rodentia: Muridae) from southern Africa - evidence for a species complex

    PubMed Central

    2010-01-01

    Background Intraspecific variation within the diverse southern African murine rodents has not been extensively investigated, yet cryptic diversity is evident in several taxa studied to date. The Namaqua rock mouse, Micaelamys namaquensis Smith, 1834 is a widespread endemic murine rodent from the subregion. Currently, a single species with four subspecies is recognised, but in the past up to 16 subspecies were described. Thus, this species is a good candidate for the investigation of patterns and processes of diversification in a diverse but under-studied mammalian subfamily and geographic region. Here, we report genetic differentiation based on mitochondrial DNA (mtDNA) cytochrome b (cyt b) sequences among samples collected over an extensive coverage of the species' range. Results Cytochrome b sequences of 360 widely sampled individuals identified 137 unique maternal alleles. Gene tree and phylogeographic analyses of these alleles suggest the presence of at least eight lineages or haplogroups (A-H), with varying degrees of intra-lineage diversity. This differentiation is in contrast with the most recent taxonomic treatment based on cranial morphometrics which only recognised four subspecies. The mtDNA diversity strongly supports earlier views that this taxon may represent a species complex. We further show statistical support for the association of several of these lineages with particular vegetation biomes of southern Africa. The time to the most recent common ancestor (TMRCA) dates to the Pliocene (~5 Mya) whereas coalescent-based divergence time estimates between lineages vary between 813 Kya [0.22 - 1.36] and 4.06 Mya [1.21 - 4.47]. The major diversification within lineages occurred during the Pleistocene. The identification of several regions of sympatry of distinct lineages offers future opportunities for the elucidation of the underlying speciation processes in the suggested species complex. Conclusions Similar to other African murine rodents, M. namaquensis radiated during the Pliocene and Pleistocene coinciding with major periods of aridification and the expansion of savanna habitats. The suggested species complex is represented by at least eight lineages of which the majority are confined to only one or a few neighbouring biomes/bioregions. Contrasting intra-lineage phylogeographic patterns suggest differences in adaptation and responses to Plio-Pleistocene climatic and vegetation changes. The role of ecological factors in driving speciation in the group needs further investigation. PMID:20942924

  16. Evidence for eight tandem and five centric fusions in the evolution of the karyotype of Aethomys namaquensis A. Smith (Rodentia: Muridae).

    PubMed

    Baker, R J; Qumsiyeh, M B; Rautenbach, I L

    1988-06-30

    G- and C-banded chromosomes of Aethomys namaquensis (2n = 24), A. chrysophilus (2n = 44), and Praomys coucha (2n = 36) are compared and contrasted with published material on Australian Muridae and North American Sigmodontidae. Direction and types of chromosomal rearrangements are established using cladistic methodology. An acrocentric morphology for chromosomes 5, 14, 15 and 20 (numbering system from Peromyscus) are proposed as primitive for the common ancestor of the Muridae and Sigmodontidae rodent lineages. Reduced diploid number of Aethomys namaquensis is derived by eight tandem and five centric fusions since divergence from the common ancestor with A. chrysophilus. The two species of Aethomys share one derived metacentric chromosome that distinguishes them from Praomys. Praomys has unique chromosomes which can be derived from the proposed primitive condition by five centric fusions and five pericentric inversions. It is concluded that karyotypic orthoselection for tandem and centric fusions is best explained by cellular or biochemical mechanisms rather than variation in population characteristics.

  17. Thaptomys Thomas 1915 (Rodentia, Sigmodontinae, Akodontini) with karyotypes 2n = 50, FN = 48, and 2n = 52, FN = 52: Two monophyletic lineages recovered by molecular phylogeny

    PubMed Central

    2010-01-01

    A novel karyotype with 2n = 50, FN = 48, was described for specimens of Thaptomys collected at Una, State of Bahia, Brazil, which are morphologically indistinguishable from Thaptomys nigrita, 2n = 52, FN = 52, found in other localities. It was hence proposed that the 2n = 50 karyotype could belong to a distinct species, cryptic of Thaptomys nigrita, once chromosomal rearrangements observed, along with the geographic distance, might represent a reproductive barrier between both forms. Phylogenetic analyses using maximum parsimony and maximum likelihood based on partial cytochrome b sequences with 1077 bp were performed, attempting to establish the relationships among the individuals with distinct karyotypes along the geographic distribution of the genus; the sample comprised 18 karyotyped specimens of Thaptomys, encompassing 15 haplotypes, from eight different localities of the Atlantic Rainforest. The intra-generic relationships corroborated the distinct diploid numbers, once both phylogenetic reconstructions recovered two monophyletic lineages, a northeastern clade grouping the 2n = 50 and a southeastern clade with three subclades, grouping the 2n = 52 karyotype. The sequence divergence observed between their individuals ranged from 1.9% to 3.5%. PMID:21637479

  18. Sarcoptic mites (Acari, Sarcoptidae) parasitizing the brown rat Rattus norvegicus (Berkenhout, 1769) (Rodentia, Muridae), with a new data for the fauna of Poland.

    PubMed

    Izdebska, Joanna N; Rolbiecki, Leszek

    2013-01-01

    One of the least researched groups of parasitic arthropods in the brown rat Rattus norvegicus (Berkenhout, 1769) are skin mites from the family of Sarcoptidae. Specimens representing two species of sarcoptic mites were found in 30 examined rats from northern Poland: Notoedres muris Megnin, 1877 and Trixacarus diversus Sellnick, 1944. The total prevalence and mean intensity of infestation were 13.3% and 3.3, respectively. At the same time, the list of sarcoptic mites occurring in Poland was completed with a new genus and new species--T. diversus.

  19. Demodectic mites of the brown rat Rattus norvegicus (Berkenhout, 1769) (Rodentia, Muridae) with a new finding of Demodex ratticola Bukva, 1995 (Acari, Demodecidae).

    PubMed

    Izdebska, Joanna N; Rolbiecki, Leszek

    2012-01-01

    Demodex ratticola was recorded in the brown rat Rattus norvegicus from northern Poland. It is a skin mite specific to this host, previously recorded only in the Czech Republic. D. ratticola was found at a prevalence 65.0% and mean intensity 12.7 in skin samples taken from the regions of lips, nose and chin. Furthermore, three other species from the family of Demodecidae were recorded, including Demodex nanus found in skin samples from different parts of the body and characterised by the highest parameters of infestation (100.0%, 25.2), D. ratti (50.0%, 3.3) found in the head skin and D. norvegicus (30.0%, 3.5) found in the genital and anal regions. The identified demodectic mites did not cause any pathological symptoms in rats.

  20. The gastrointestinal helminths of Rattus niobe (Rodentia: Muridae) with descriptions of two new genera and three new species (Nematoda) from Papua New Guinea and Papua Indonesia.

    PubMed

    Smales, L R

    2016-05-31

    Cestodes, to be identified elsewhere, the acanthocephalan Moniliformis moniliformis and 15 species of nematode including 2 new genera, a new species and 2 putative new species from the families Heligmonellidae and Oxyuridae, as well as juveniles and a putative heligmonellid that could not be fully identified, were collected from the digestive tracts of 34 Rattus niobe (Muridae: Murinae: Rattini) from Papua, Indonesia and Papua New Guinea. The ascaridid, Toxocara mackerrasae, the chabertiid Cyclodontostomum purvisi, the heterakid Heterakis sp., the spirurids Protospirura kaindiensis and P. muricola the subulurid Subulura andersoni and the trichurids Eucoleus sp. and Trichuris muris have been reported previously from endemic Rattus spp. Syphacia (Syphacia) niobe n. sp. was distinguished from its congeners by a combination of characters including a round cephalic plate, the lack of cervical and lateral alae, a longer male tail and an attenuated female tail. Nugininema titokis n. gen., n. sp. differs from all other genera in the Heligmonellidae in the characters of the synlophe, 10-17 ridges orientated subfrontally at mid body and 2 right ventral ridges hypertrophied anteriorly. Rodentanema aenigma n. gen., n. sp. differs from all other genera in the Heligmonellidae in the characters of the synlophe 6-7 ridges at mid body not symmetrical in relation to frontal axis. Species richness of the nematode assemblage was similar to that reported for Rattus leucopus in Papua New Guinea, with about 90% of possible species found as indicated by bootstrap analysis. Species composition included 6 species unique to R. niobe and 7 species reported from at least one other species of Rattus indigenous to New Guinea, as well as juvenile worms, probably ascaridids.

  1. Endogenous development, pathogenicity and host specificity of Eimeria cahirinensis Couch, Blaustein, Duszynski, Shenbrot and Nevo, 1997 (Apicomplexa: Eimeriidae) from Acomys dimidiatus (Cretzschmar 1826) (Rodentia: Muridae) from the Near East.

    PubMed

    Kvicerová, Jana; Ptácková, Pavla; Modrý, David

    2007-01-01

    Eimeria cahirinensis Couch et al. 1997 was found in faecal samples of Acomys dimidiatus from three different localities in the Near East. Twenty-two of 104 (21%) A. dimidiatus trapped on both the south- and north-facing slopes of "Evolution Canyon", Lower Nahal Oren, Mt. Carmel, Israel in August 2001 and 2002 were infected with E. cahirinensis. Oocysts were also obtained from a single individual of A. dimidiatus trapped in Wadi Ramm, Jordan in the summer of 1999. Laboratory-reared spiny mice (Acomys spp.) were inoculated to determine the prepatent and patent period, sporulation time, site of infection, immunogenicity, pathogenicity, pathology and morphology of endogenous stages of E. cahirinensis. Both asexual and sexual stages were localised in the apical part of duodenal and jejunal villi. An experimental inoculation of representatives of several rodent genera revealed the host range of E. cahirinensis to be limited to the genus Acomys.

  2. [Genetic variation and phylogeography of the bank vole (Clethrionomys glareolus, Arvicolinae, Rodentia) in Russia with special reference to the introgression of the mtDNA of a closely related species, red-backed vole (C. rutilus)].

    PubMed

    Abramson, N I; Rodchenkova, E N; Kostygov, A Iu

    2009-05-01

    Totally, 294 bank voles (Clethrionomys glareolus) and 18 red-backed voles (C. rutilus) from 62 sites of European Russia were studied. Incomplete sequences (967 bp) of the mitochondrial cytochrome b gene were determined for 93 C. glareolus individuals from 56 sites and 18 C. rutilus individuals from the same habitats. Analysis of the cytochrome b gene variation has demonstrated that practically the entire European part of Russia, Ural, and a considerable part of Western Europe are inhabited by bank voles of the same phylogroup, displaying an extremely low genetic differentiation. Our data suggest that C. glareolus very rapidly colonized over the presently occupied territory in the post-Pleistocene period from no more than two (central European and western European) refugia for ancestral populations with a small efficient size. PCR typing of the mitochondrial cytochrome b gene allowed us to assess the scale of mtDNA introgression from a closely related species, C. rutilus, and to outline the geographical zone of this introgression. Comparison with the red-backed vole haplotypes in the habitats shared by both species favors the hypothesis of an ancient hybridization event (mid-Holocene) and a subsequent introgression. These results suggest that the hybridization took place in the southern and middle Pre-Ural region.

  3. First report of Siphonaptera infesting Microtus (Microtus) cabrerae (Rodentia-Muridae-Arvicolinae) in Cuenca, Spain and notes about the morphologic variability of Ctenophthalmus (Ctenophthalmus) apertus personatus (Insecta-Siphonaptera-Ctenophthalmidae).

    PubMed

    Gómez, M S; Fernández-Salvador, R; Garcia, R

    2003-06-01

    The fleas infesting Microtus (Microtus) cabrerae from three different areas of Cuenca province (Spain) have been studied. It is the first time that on ectoparasitological study of this badly known rodent has been done. Four Siphonaptera species have been detected: Rhadinopsylla (Actenophthalmus) pentacantha, Peromyscopsylla spectabilis spectabilis, Nosopsyllus fasciatus and Ctenophthalmus (Ctenophthalmus) apertus personatus, which was the most abundant species (26 males and 31 females of a total of 28 males and 35 females). Considering the great morphologic variability within the male processus basimerus ventralis (p.b.v.) of segment IX of C. personatus subspecies, three morphotypes have been recognised. The male polymorphism detected, would be the result of both host confinement and genetic selection acting on the parasite. It should be pointed out that C. (C.) apertus personatus is not narrowly host-specific, therefore further studies are required to clarify this taxonomic situation.

  4. Redescription of Heligmosomoides neopolygyrus, Asakawa and Ohbayashi, 1986 (Nematoda: Heligmosomidae) from a Chinese rodent, Apodemus peninsulae (Rodentia: Muridae); with comments on Heligmosomoides polygyrus polygyrus (Dujardin, 1845) and related species in China and Japan.

    PubMed

    Massoni, J; Durette-Desset, M C; Quéré, J P; Audebert, F

    2012-11-01

    Heligmosomoides neopolygyrus, Asakawa and Ohbayashi, 1986 (Nematoda, Heligmosomoidea) is redescribed from Apodemus peninsulae from Rangtang, Sichuan, China. A morphological review of the Heligmosomoides spp. belonging to the "polygyrus line" proposed by Asakawa (1988) is made using new characters. This enabled us to distinguish two subspecies in Mus musculus (Heligmosomoides polygyrus bakeri from Japan and H. p. polygyrus from China) and two valid species in Apodemus spp. (H. neopolygyrus from Japan (in A. peninsulae) and from China (in A. agrarius) and H. asakawae from China (in A. uralensis)). Three parasite species of A. agrarius and A. peninsulae, previously identified by Asakawa et al. (1993) as H. neopolygyrus, are considered to be Heligmosomoides incertae sedis. This is the first report of H. neopolygyrus in A. peninsulae from China.

  5. [Morphology and biometry of eggs and larvae of Strongyloides sp. Grassi, 1879 (Rhabditoidea: Strongyloididae), a gastrointestinal parasite of Hydrochaeris hydrochaeris (Linnaeus, 1766) (Rodentia: Hydrochaeridae), in the municipality of Juiz de Fora, Minas Gerais, Brazil].

    PubMed

    Vieira, Fabiano M; Lima, Sueli de S; Bessa, Elisabeth Cristina de A

    2006-01-01

    An important method to diagnose and study the helminthofauna of wild animals is to examine the host's feces to find eggs and larvae, seeking to identify the parasites and study their morphobiology. The objective of the present work is to provide morphological and biometric data on the eggs and larvae of Strongyloides sp., a capybara gastrointestinal parasite. Using the technique of Gordon and Whitlock, simple flotation and the modified Baermann examination, capybara fecal samples were selected based on a criterion of the highest proportion of eggs and larvae in the initial development stages, for morphometric description of eggs, L1, L2 and L3 of Strongyloides sp. From past reports of parasitism in Hydrochaeris hydrochaeris, we suspect that the eggs and larvae in this study are of Strongyloides chapini Sandground, 1925, which constitutes the first description of these stages for this species of nematode. Nevertheless, the morphology and biometry data of these stages demonstrate that they are similar to those of other species of the Strongyloides genus.

  6. Expression of androgen receptor, estrogen receptors alpha and beta and aromatase in the fetal, perinatal, prepubertal and adult testes of the South American plains Vizcacha, Lagostomus maximus (Mammalia, Rodentia).

    PubMed

    González, Candela Rocío; Muscarsel Isla, María Laura; Leopardo, Noelia Paola; Willis, Miguel Alfredo; Dorfman, Verónica Berta; Vitullo, Alfredo Daniel

    2012-01-01

    Androgens and androgen receptor play a critical role in spermatogenesis and fertility in mammals, and estrogens and their receptors contribute to regulation of testicular function through initiation and maintenance of spermatogenesis and germ cell division and survival. However, results from different species are still far from establishing a clear understanding of these receptors in the different cell types from the testis. We analyzed the expression of androgen receptor, estrogen receptors α and β and aromatase protein by immunohistochemistry and real-time PCR, in relation to proliferation followed by the expression of proliferation cell nuclear antigen (PCNA) and germinal identity by VASA protein, in fetal, perinatal, prepubertal and adult testes of Lagostomus maximus, a rodent with sustained germ cell proliferation and an increasing number of OCT-4-expressing gonocytes in the developing ovary. AR expression was restricted to Leydig cells and peritubular cells before sexual maturity, at which point it also became expressed in Sertoli cells. ERα and ERβ were expressed in seminiferous tubules and the interstitium, respectively, in both fetal and prepubertal testes. In adult testes, both ERα and ERβ co-localized in Leydig and peritubular cells. The aromatase enzyme, which converts androgenic precursors into estrogens, was detectable in all developmental stages analyzed and was restricted to Leydig cells. PCNA remained high until sexual maturity. ERα nuclear detection in germ cells and AR in Leydig cells in PCNA-positive cells suggest the possibility of a stimulatory effect of estrogens on spermatogonia proliferation. This effect might explain the increase found in VASA-expressing cells in the adult testis.

  7. Parasites of mammals on the Sevilleta National Wildlife Refuge, Socorro, New Mexico: Cuterebra austeni and C. neomexicana (Diptera:Oestridae) from Neotoma and Peromyscus (Rodentia:Muridae), 1991-1994.

    PubMed

    Wilson, W D; Hnida, J A; Duszynski, D W

    1997-05-01

    In total, 6,486 rodents representing 3 families (Muridae, Heteromyidae, and Sciuridae) and 24 species were trapped May through August of 1991 through 1994. Of these, only the white-throated woodrat. Neotoma albigula Hartley; piñon mouse, Peromyscus truei Shufeldt; and white-footed mouse, P. leucopus Rafinesque, were infested with Cuterebra Clark larvae. Of the 594 N. albigula that were captured 103 (17.3%) were infested with 139 Cuterebra larvae with all infestations occurring in the throat region. N. albigula infestations were observed in 4 of 5 habitats sampled. The highest prevalence of infestation occurred during May-June (27.2%) versus July-August (9.1%) and in males (25.2%) versus females (18.3%). Prevalence of infestation was not significantly different between animals from the mark-release webs versus removal webs or adults versus juveniles. Also, there was no correlation between relative density of N. albigula and prevalence of infestation. Fifteen adults were reared from puparia and identified as C. austeni Sabrosky. Of 716 P. truei captured, 22 (3.1%) were infested with a total of 25 Cuterebra larvae with all infestations occurring in the scapular region. Although P. truei were captured in all 5 habitats, they were only infested in the piñon-juniper habitat: the highest prevalence of infestation occurred during July-August (10.9%) versus May-June (3.3%). Prevalence of infestation was not significantly different between animals from mark-release webs versus removal webs, males versus females, or adults versus juveniles. As in the N. albigula, there was no correlation between relative density of P. truei and prevalence of infestation. The adult reared from a puparium was identified as C. neomexicana Sabrosky. Of the 310 P. leucopus captured, only 3 (1%) were infested with Cuterebra larvae.

  8. About rats and jackfruit trees: modeling the carrying capacity of a Brazilian Atlantic Forest spiny-rat Trinomys dimidiatus (Günther, 1877) - Rodentia, Echimyidae - population with varying jackfruit tree (Artocarpus heterophyllus L.) abundances.

    PubMed

    Mello, J H F; Moulton, T P; Raíces, D S L; Bergallo, H G

    2015-01-01

    We carried out a six-year study aimed at evaluating if and how a Brazilian Atlantic Forest small mammal community responded to the presence of the invasive exotic species Artocarpus heterophyllus, the jackfruit tree. In the surroundings of Vila Dois Rios, Ilha Grande, RJ, 18 grids were established, 10 where the jackfruit tree was present and eight were it was absent. Previous results indicated that the composition and abundance of this small mammal community were altered by the presence and density of A. heterophyllus. One observed effect was the increased population size of the spiny-rat Trinomys dimidiatus within the grids where the jackfruit trees were present. Therefore we decided to create a mathematical model for this species, based on the Verhulst-Pearl logistic equation. Our objectives were i) to calculate the carrying capacity K based on real data of the involved species and the environment; ii) propose and evaluate a mathematical model to estimate the population size of T. dimidiatus based on the monthly seed production of jackfruit tree, Artocarpus heterophyllus and iii) determinate the minimum jackfruit tree seed production to maintain at least two T. dimidiatus individuals in one study grid. Our results indicated that the predicted values by the model for the carrying capacity K were significantly correlated with real data. The best fit was found considering 20~35% energy transfer efficiency between trophic levels. Within the scope of assumed premises, our model showed itself to be an adequate simulator for Trinomys dimidiatus populations where the invasive jackfruit tree is present.

  9. Effects of Isolation by Continental Islands in the Seto Inland Sea, Japan, on Genetic Diversity of the Large Japanese Field Mouse, Apodemus speciosus (Rodentia: Muridae), Inferred from the Mitochondrial Dloop Region.

    PubMed

    Sato, Jun J; Tasaka, Yurina; Tasaka, Ryoya; Gunji, Kentaro; Yamamoto, Yuya; Takada, Yasushi; Uematsu, Yasushi; Sakai, Eiichi; Tateishi, Takashi; Yamaguchi, Yasunori

    2017-04-01

    To study the effects of post-glacial isolation by islands on population genetic diversity and differentiation of the large Japanese field mouse, Apodemus speciosus, we examined partial nucleotide sequences of the mitochondrial Dloop region (ca. 300 bp) in 231 individuals collected from islands in the Seto Inland Sea and adjacent regions on Honshu and Shikoku Islands in the western part of the Japanese archipelago. Molecular phylogenetic and network analyses showed that haplotypes in each island tended to form monophyletic groups, while those in Honshu and Shikoku (the major Japanese islands) showed scattered relationships and were connected with island haplotypes. These observations suggest that a set of Honshu and Shikoku haplotypes became the ancestral lineages of the island population. No gene flow was detected among island populations, indicating that independent evolution occurred on each island, without the influence of human activities, since the establishment of the islands in the Holocene. Population genetic diversities on each island were lower than those on Honshu and Shikoku. Comparison between genetic diversity and island area size showed positive correlations and supported the suggestion that genetic drift is a major factor that shaped the current haplotype constitution of the islands in the Seto Inland Sea.

  10. Gastrointestinal helminths (Cestoda, Chabertiidae and Heligmonellidae) of Pogonomys loriae and Pogonomys macrourus (Rodentia: Muridae) from Papua Indonesia and Papua New Guinea with the description of a new genus and two new species.

    PubMed

    Smales, L R

    2014-11-28

    Pieces of cestode, not indentified further, and 12 species of nematode including 1 new genus, 3 new species and 7 putative new species from the Families Chabertiidae and Heligmonellidae were collected from the digestive tracts of 16 Pogonomys loriae and 19 P. macrurous (Murinae: Hydromyini) from Papua, Indonesia and Papua New Guinea. The chabertiid Cyclodontostomum purvisi and the heligmonellid Odilia mackerrasae have been described previously from endemic murids. Hasanuddinia pogonomyos n. sp. can be distinguished from its congeners by the number of ridges in the synlophe, length of spicules and having a vagina with a dorsal diverticulum. Odilia dividua n. sp. is larger than its congeners, has a longer oesophagus, relatively shorter spicules and larger eggs. Pogonomystrongylus domaensis n. gen., n. sp. differs from all other genera in the Heligmonellidae in the characters of the synlophe, 7-10 ridges oriented sub frontally with a single left ventral ridge hypertrophied. Species richness of the nematode assemblages of P. loriae and P. macrourus are comparable to those of Abeomelomys sevia, Chiruromys vates and Coccymys rummleri when numbers of hosts examined are considered. Species composition was distinctive with 12, including the 7 putative species, of 14 species presently known only from species of Pogonomys. Similarities between the nematode fauna of endemic rodent hosts from Indonesia and Papua New Guinea were noted.

  11. Involvement of pre- and post-synaptic serotonergic receptors of dorsal raphe nucleus neural network in the control of the sweet-substance-induced analgesia in adult Rattus norvegicus (Rodentia, Muridae).

    PubMed

    Miyase, Cátia Isumi; Kishi, Renato; de Freitas, Renato Leonardo; Paz, Denise Amorim; Coimbra, Norberto Cysne

    2005-05-13

    In order to investigate the effects of monoaminergic mechanisms of the dorsal raphe nucleus on the elaboration and control of sweet-substance-induced antinociception, male albino Wistar rats weighing 180-200 g received sucrose solution (250 g/L) for 14 days as their only source of liquid. After the chronic consumption of sucrose solution, each animal was pretreated with unilateral microinjection of methiothepin mesylate (5.0 microg/0.2 microL), or methysergide maleate (5.0 microg/0.2 microL) in the dorsal raphe nucleus. Each rat consumed an average of 15.6g sucrose/day. Their tail withdrawal latencies in the tail-flick test were measured immediately before and after this treatment. An analgesia index was calculated from the withdrawal latencies before and after the pharmacological treatment. The blockade of serotonergic receptor in the dorsal raphe nucleus with methysergide after the chronic intake of sucrose decreased the sweet-induced antinociception. However, microinjections of methiothepin in the dorsal raphe nucleus did not cause a similar effect on the tail-flick latencies after the chronic intake of sucrose solution, increasing the sweet-substance-induced analgesia. These results indicate the involvement of serotonin as a neurotransmitter in the sucrose-produced antinociception. Considering that the blockade of pre-synaptic serotonergic receptors of the neural networks of the dorsal raphe nucleus with methiothepin did not decrease the sweet-substance-induced antinociception, and the central blockade of post-synaptic serotonergic receptors decreased the sucrose-induced analgesia, the modulation of the release of serotonin in the neural substrate of the dorsal raphe nucleus seems to be crucial for the organization of this interesting antinociceptive process.

  12. Genomics, biogeography, and the diversification of placental mammals

    PubMed Central

    Wildman, Derek E.; Uddin, Monica; Opazo, Juan C.; Liu, Guozhen; Lefort, Vincent; Guindon, Stephane; Gascuel, Olivier; Grossman, Lawrence I.; Romero, Roberto; Goodman, Morris

    2007-01-01

    Previous molecular analyses of mammalian evolutionary relationships involving a wide range of placental mammalian taxa have been restricted in size from one to two dozen gene loci and have not decisively resolved the basal branching order within Placentalia. Here, on extracting from thousands of gene loci both their coding nucleotide sequences and translated amino acid sequences, we attempt to resolve key uncertainties about the ancient branching pattern of crown placental mammals. Focusing on ≈1,700 conserved gene loci, those that have the more slowly evolving coding sequences, and using maximum-likelihood, Bayesian inference, maximum parsimony, and neighbor-joining (NJ) phylogenetic tree reconstruction methods, we find from almost all results that a clade (the southern Atlantogenata) composed of Afrotheria and Xenarthra is the sister group of all other (the northern Boreoeutheria) crown placental mammals, among boreoeutherians Rodentia groups with Lagomorpha, and the resultant Glires is close to Primates. Only the NJ tree for nucleotide sequences separates Rodentia (murids) first and then Lagomorpha (rabbit) from the other placental mammals. However, this nucleotide NJ tree still depicts Atlantogenata and Boreoeutheria but minus Rodentia and Lagomorpha. Moreover, the NJ tree for amino acid sequences does depict the basal separation to be between Atlantogenata and a Boreoeutheria that includes Rodentia and Lagomorpha. Crown placental mammalian diversification appears to be largely the result of ancient plate tectonic events that allowed time for convergent phenotypes to evolve in the descendant clades. PMID:17728403

  13. Phylogenetic analyses of complete mitochondrial genome sequences suggest a basal divergence of the enigmatic rodent Anomalurus

    PubMed Central

    Horner, David S; Lefkimmiatis, Konstantinos; Reyes, Aurelio; Gissi, Carmela; Saccone, Cecilia; Pesole, Graziano

    2007-01-01

    Background Phylogenetic relationships between Lagomorpha, Rodentia and Primates and their allies (Euarchontoglires) have long been debated. While it is now generally agreed that Rodentia constitutes a monophyletic sister-group of Lagomorpha and that this clade (Glires) is sister to Primates and Dermoptera, higher-level relationships within Rodentia remain contentious. Results We have sequenced and performed extensive evolutionary analyses on the mitochondrial genome of the scaly-tailed flying squirrel Anomalurus sp., an enigmatic rodent whose phylogenetic affinities have been obscure and extensively debated. Our phylogenetic analyses of the coding regions of available complete mitochondrial genome sequences from Euarchontoglires suggest that Anomalurus is a sister taxon to the Hystricognathi, and that this clade represents the most basal divergence among sampled Rodentia. Bayesian dating methods incorporating a relaxed molecular clock provide divergence-time estimates which are consistently in agreement with the fossil record and which indicate a rapid radiation within Glires around 60 million years ago. Conclusion Taken together, the data presented provide a working hypothesis as to the phylogenetic placement of Anomalurus, underline the utility of mitochondrial sequences in the resolution of even relatively deep divergences and go some way to explaining the difficulty of conclusively resolving higher-level relationships within Glires with available data and methodologies. PMID:17288612

  14. Spot-on Treatments of Diflubenzuron and Permethrin to Control a Guinea Pig Louse, Gliricola Porcelli (Phthiraptera: Gyropidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Guinea pigs (Cavia porcellus (L.)) (Rodentia: Caviidae) are pets and laboratory animals. They can be infested by a chewing louse, Gliricola porcelli (Schrank) (Phthiraptera: Gyropidae), which is fairly common in some animal rearing facilities, pet stores, and on wild guinea pigs. Infestation with G....

  15. Karyotypic evolution of the family Sciuridae: inferences from the genome organizations of ground squirrels.

    PubMed

    Li, T; Wang, J; Su, W; Nie, W; Yang, F

    2006-01-01

    Cross-species chromosome painting has made a great contribution to our understanding of the evolution of karyotypes and genome organizations of mammals. Several recent papers of comparative painting between tree and flying squirrels have shed some light on the evolution of the family Sciuridae and the order Rodentia. In the present study we have extended the comparative painting to the Himalayan marmot (Marmotahimalayana) and the African ground squirrel (Xerus cf. erythropus), i.e. representative species from another important squirrel group--the ground squirrels--, and have established genome-wide comparative chromosome maps between human, eastern gray squirrel, and these two ground squirrels. The results show that 1) the squirrels so far studied all have conserved karyotypes that resemble the ancestral karyotype of the order Rodentia; 2) the African ground squirrels could have retained the ancestral karyotype of the family Sciuridae. Furthermore, we have mapped the evolutionary rearrangements onto a molecular-based consensus phylogenetic tree of the family Sciuridae.

  16. Comparative genetics of longevity and cancer: insights from long-lived rodents

    PubMed Central

    Gorbunova, Vera; Seluanov, Andrei; Zhang, Zhengdong; Gladyshev, Vadim N.; Vijg, Jan

    2015-01-01

    Mammals have evolved a dramatic diversity of aging rates. Within the single order of Rodentia maximum lifespans differ from four years in mice to 32 years in naked mole rats. Cancer rates also differ significantly, from cancer-prone mice to virtually cancer-proof naked and blind mole rats. Recent progress in rodent comparative biology, in combination with the emergence of whole genome sequence information, has opened opportunities for the discovery of genetic factors controlling longevity and cancer susceptibility. PMID:24981598

  17. Mites of the genus Schizocarpus Trouessart, 1896 (Acariformes: Chirodiscidae) from the North American beavers (Castor canadensis) in Russia.

    PubMed

    Bochkov, A V; Saveljev, A P

    2014-01-01

    Four native species of parasitic mites belonging to the genus Schizocarpus Trouessart, 1896 (Acariformes: Chirodiscidae) are recorded on the North American beaver Castor canadensis Kuhl, 1820 (Rodentia: Castoridae) from Russia. Totally ten beavers from all three main geographically isolated populations of in Russia (Leningrad Province, Voronezh Biosphere Reserve (beaver farm) and Khabarovsk Territory) were examined. Additionally, in captivity (Voronezh beaver farm) eight species were recorded switched from the Eurasian beaver Castor fiber Linnaeus, 1758 on C. canadensis.

  18. Why can't rodents vomit? A comparative behavioral, anatomical, and physiological study.

    PubMed

    Horn, Charles C; Kimball, Bruce A; Wang, Hong; Kaus, James; Dienel, Samuel; Nagy, Allysa; Gathright, Gordon R; Yates, Bill J; Andrews, Paul L R

    2013-01-01

    The vomiting (emetic) reflex is documented in numerous mammalian species, including primates and carnivores, yet laboratory rats and mice appear to lack this response. It is unclear whether these rodents do not vomit because of anatomical constraints (e.g., a relatively long abdominal esophagus) or lack of key neural circuits. Moreover, it is unknown whether laboratory rodents are representative of Rodentia with regards to this reflex. Here we conducted behavioral testing of members of all three major groups of Rodentia; mouse-related (rat, mouse, vole, beaver), Ctenohystrica (guinea pig, nutria), and squirrel-related (mountain beaver) species. Prototypical emetic agents, apomorphine (sc), veratrine (sc), and copper sulfate (ig), failed to produce either retching or vomiting in these species (although other behavioral effects, e.g., locomotion, were noted). These rodents also had anatomical constraints, which could limit the efficiency of vomiting should it be attempted, including reduced muscularity of the diaphragm and stomach geometry that is not well structured for moving contents towards the esophagus compared to species that can vomit (cat, ferret, and musk shrew). Lastly, an in situ brainstem preparation was used to make sensitive measures of mouth, esophagus, and shoulder muscular movements, and phrenic nerve activity-key features of emetic episodes. Laboratory mice and rats failed to display any of the common coordinated actions of these indices after typical emetic stimulation (resiniferatoxin and vagal afferent stimulation) compared to musk shrews. Overall the results suggest that the inability to vomit is a general property of Rodentia and that an absent brainstem neurological component is the most likely cause. The implications of these findings for the utility of rodents as models in the area of emesis research are discussed.

  19. Phylogenetic positions of insectivora in eutheria inferred from mitochondrial cytochrome c oxidase subunit II gene.

    PubMed

    Onuma, M; Kusakabe, T; Kusakabe, S

    1998-02-01

    For the elucidation of the phylogenetic position of insectivora in eutheria, we have sequenced the cytochrome c oxidase subunit II (COII) gene of mitochondria for three insectivoran species [musk screw (Suncus murinus), shrew mole (Urotrichus talpoides), Japanese mole (Mogera wogura)] and analyzed these amino acid sequences with neighbor-joining (NJ) method and maximum likelihood (ML) method. NJ analysis shows polyphyly of Insectivora and Chiroptera. Assuming that each of Primates, Ferungulata, Chiroptera, Insectivora and Rodentia is a monophyletic group, ML analysis suggests that Chiroptera is a sister group of Insectivora and that Ferungulata is the closest outgroup to the (Insectivora and Chiroptera) clade.

  20. Anatomy and Disorders of the Oral Cavity of Rat-like and Squirrel-like Rodents.

    PubMed

    Mancinelli, Elisabetta; Capello, Vittorio

    2016-09-01

    The order Rodentia comprises more than 2000 species divided into 3 groups based on anatomic and functional differences of the masseter muscle. Myomorph and sciuromorph species have elodont incisors and anelodont cheek teeth, unlike hystrichomorph species which have full anelodont dentition. Diseases of incisors and cheek teeth of rat-like and squirrel-like rodents result in a wide variety of symptoms and clinical signs. Appropriate diagnostic testing and imaging techniques are required to obtain a definitive diagnosis, formulate a prognosis, and develop a treatment plan. A thorough review of elodontoma, odontoma, and pseudo-odontoma is provided, including treatment of pseudo-odontomas in prairie dogs.

  1. Sexing the Sciuridae: a simple and accurate set of molecular methods to determine sex in tree squirrels, ground squirrels and marmots.

    PubMed

    Gorrell, Jamieson C; Boutin, Stan; Raveh, Shirley; Neuhaus, Peter; Côté, Steeve D; Coltman, David W

    2012-09-01

    We determined the sequence of the male-specific minor histocompatibility complex antigen (Smcy) from the Y chromosome of seven squirrel species (Sciuridae, Rodentia). Based on conserved regions inside the Smcy intron sequence, we designed PCR primers for sex determination in these species that can be co-amplified with nuclear loci as controls. PCR co-amplification yields two products for males and one for females that are easily visualized as bands by agarose gel electrophoresis. Our method provides simple and reliable sex determination across a wide range of squirrel species.

  2. Trichuris eggs in animal coprolites dated from 30,000 years ago.

    PubMed

    Ferreira, L F; Araújo, A; Confalonieri, U; Chame, M; Gomes, D C

    1991-06-01

    Trichuris eggs were found in Kerodon rupestris (Rodentia, Caviidae) coprolites collected in archaeological layers dated from 30,000 yr BP (before present) to 8,450 yr BP. Adult worms and eggs of this genus were not found in a search of living mammals of the region. Results indicate that K. rupestris was a host for an unknown Trichuris species not found in this rodent presently. Climate changes that occurred by 10,000 yr ago in the region could be the cause of its disappearance. The finding of parasites in archaeological material can show the antiquity of host-parasite relationships and parasite losses through time.

  3. Discrepancy variation of dinucleotide microsatellite repeats in eukaryotic genomes.

    PubMed

    Gao, Huan; Cai, Shengli; Yan, Binlun; Chen, Baiyao; Yu, Fei

    2009-01-01

    To address whether there are differences of variation among repeat motif types and among taxonomic groups, we present here an analysis of variation and correlation of dinucleotide microsatellite repeats in eukaryotic genomes. Ten taxonomic groups were compared, those being primates, mammalia (excluding primates and rodentia), rodentia, birds, fish, amphibians and reptiles, insects, molluscs, plants and fungi, respectively. The data used in the analysis is from the literature published in the Journal of Molecular Ecology Notes. Analysis of variation reveals that there are no significant differences between AC and AG repeat motif types. Moreover, the number of alleles correlates positively with the copy number in both AG and AC repeats. Similar conclusions can be obtained from each taxonomic group. These results strongly suggest that the increase of SSR variation is almost linear with the increase of the copy number of each repeat motif. As well, the results suggest that the variability of SSR in the genomes of low-ranking species seem to be more than that of high-ranking species, excluding primates and fungi.

  4. Molecular evolution of the nuclear von Willebrand factor gene in mammals and the phylogeny of rodents.

    PubMed

    Huchon, D; Catzeflis, F M; Douzery, E J

    1999-05-01

    Nucleotide sequences of exon 28 of the von Willebrand Factor (vWF) were analyzed for a representative sampling of rodent families and eutherian orders, with one marsupial sequence as outgroup. The aim of this study was to test if inclusion of an increased taxonomic diversity in molecular analyses would shed light on three uncertainties concerning rodent phylogeny: (1) relationships between rodent families, (2) Rodentia monophyly, and (3) the sister group relationship of rodents and lagomorphs. The results did not give evidence of any particular rodent pattern of molecular evolution relative to a general eutherian pattern. Base compositions and rates of evolution of vWF sequences of rodents were in the range of placental variation. The 10 rodent families studied here cluster in five clades: Hystricognathi, Sciuridae and Aplodontidae (Sciuroidea), Muridae, Dipodidae, and Gliridae. Among hystricognaths, the following conclusions are drawn: a single colonization event in South America by Caviomorpha, a paraphyly of Old World and New World porcupines, and an African origin for Old World porcupines. Despite a broader taxonomic sampling diversity, we did not obtain a robust answer to the question of Rodentia monophyly, but in the absence of any other alternative, we cannot reject the hypothesis of a single origin of rodents. Moreover, the phylogenetic position of Lagomorpha remains totally unsettled.

  5. Molecular Individual-Based Approach on Triatoma brasiliensis: Inferences on Triatomine Foci, Trypanosoma cruzi Natural Infection Prevalence, Parasite Diversity and Feeding Sources

    PubMed Central

    Almeida, Carlos Eduardo; Faucher, Leslie; Lavina, Morgane; Costa, Jane; Harry, Myriam

    2016-01-01

    We used an individual-based molecular multisource approach to assess the epidemiological importance of Triatoma brasiliensis collected in distinct sites and ecotopes in Rio Grande do Norte State, Brazil. In the semi-arid zones of Brazil, this blood sucking bug is the most important vector of Trypanosoma cruzi—the parasite that causes Chagas disease. First, cytochrome b (cytb) and microsatellite markers were used for inferences on the genetic structure of five populations (108 bugs). Second, we determined the natural T. cruzi infection prevalence and parasite diversity in 126 bugs by amplifying a mini-exon gene from triatomine gut contents. Third, we identified the natural feeding sources of 60 T. brasiliensis by using the blood meal content via vertebrate cytb analysis. Demographic inferences based on cytb variation indicated expansion events in some sylvatic and domiciliary populations. Microsatellite results indicated gene flow between sylvatic and anthropic (domiciliary and peridomiciliary) populations, which threatens vector control efforts because sylvatic population are uncontrollable. A high natural T. cruzi infection prevalence (52–71%) and two parasite lineages were found for the sylvatic foci, in which 68% of bugs had fed on Kerodon rupestris (Rodentia: Caviidae), highlighting it as a potential reservoir. For peridomiciliary bugs, Galea spixii (Rodentia: Caviidae) was the main mammal feeding source, which may reinforce previous concerns about the potential of this animal to link the sylvatic and domiciliary T. cruzi cycles. PMID:26891047

  6. Masticatory (;superfast') myosin heavy chain and embryonic/atrial myosin light chain 1 in rodent jaw-closing muscles.

    PubMed

    Reiser, Peter J; Bicer, Sabahattin; Chen, Qun; Zhu, Ling; Quan, Ning

    2009-08-01

    Masticatory myosin is widely expressed among several vertebrate classes. Generally, the expression of masticatory myosin has been associated with high bite force for a carnivorous feeding style (including capturing/restraining live prey), breaking down tough plant material and defensive biting in different species. Masticatory myosin expression in the largest mammalian order, Rodentia, has not been reported. Several members of Rodentia consume large numbers of tree nuts that are encased in very hard shells, presumably requiring large forces to access the nutmeat. We, therefore, tested whether some rodent species express masticatory myosin in jaw-closing muscles. Myosin isoform expression in six Sciuridae species was examined, using protein gel electrophoresis, immunoblotting, mass spectrometry and RNA analysis. The results indicate that masticatory myosin is expressed in some Sciuridae species but not in other closely related species with similar diets but having different nut-opening strategies. We also discovered that the myosin light chain 1 isoform associated with masticatory myosin heavy chain, in the same four Sciuridae species, is the embryonic/atrial isoform. We conclude that rodent speciation did not completely eliminate masticatory myosin and that its persistent expression in some rodent species might be related to not only diet but also to feeding style.

  7. Molecular Individual-Based Approach on Triatoma brasiliensis: Inferences on Triatomine Foci, Trypanosoma cruzi Natural Infection Prevalence, Parasite Diversity and Feeding Sources.

    PubMed

    Almeida, Carlos Eduardo; Faucher, Leslie; Lavina, Morgane; Costa, Jane; Harry, Myriam

    2016-02-01

    We used an individual-based molecular multisource approach to assess the epidemiological importance of Triatoma brasiliensis collected in distinct sites and ecotopes in Rio Grande do Norte State, Brazil. In the semi-arid zones of Brazil, this blood sucking bug is the most important vector of Trypanosoma cruzi--the parasite that causes Chagas disease. First, cytochrome b (cytb) and microsatellite markers were used for inferences on the genetic structure of five populations (108 bugs). Second, we determined the natural T. cruzi infection prevalence and parasite diversity in 126 bugs by amplifying a mini-exon gene from triatomine gut contents. Third, we identified the natural feeding sources of 60 T. brasiliensis by using the blood meal content via vertebrate cytb analysis. Demographic inferences based on cytb variation indicated expansion events in some sylvatic and domiciliary populations. Microsatellite results indicated gene flow between sylvatic and anthropic (domiciliary and peridomiciliary) populations, which threatens vector control efforts because sylvatic population are uncontrollable. A high natural T. cruzi infection prevalence (52-71%) and two parasite lineages were found for the sylvatic foci, in which 68% of bugs had fed on Kerodon rupestris (Rodentia: Caviidae), highlighting it as a potential reservoir. For peridomiciliary bugs, Galea spixii (Rodentia: Caviidae) was the main mammal feeding source, which may reinforce previous concerns about the potential of this animal to link the sylvatic and domiciliary T. cruzi cycles.

  8. Stereo architecture of the connective tissue cores of the lingual papillae in the treeshrew (Tupaia glis).

    PubMed

    Kobayashi, K; Wanichanon, C

    1992-12-01

    The stereo architecture of the lingual connective tissue cores (CTC) in the treeshrew (Tupaia glis) (which has the primitive characteristics of primates) was observed by scanning electron microscopy, and compared to that of other animal orders. The tongue of the treeshrew has three vallate papillae which are situated in the posterior part of the tongue, while some macaques have several vallate papillae. Among numerous filiform papillae, fungiform papillae are sporadically distributed. A filiform papilla consists of a bundle of several slender spine-like processes arranged in a circle at the basal margin. After removal of the epithelium, the CTC of the filiform papilla looks like a human hand raised with the palm facing towards the tongue tip. The fungiform CTC in the threeshrew is columnar in shape (rather similar to that of Insectivora and Rodentia) and at the top there are several round depressions for taste buds. In the treeshrew several large rod-shaped processes are derived from the postero-lateral margin of the tongue, as in Carnivora (dogs and cats), where foliate papillae are located in many other animal species. The treeshrew has numerous characteristics similar to those of the crab-eating macaque (Primates), but at the same time it has some characteristics similar to those of Insectivora, Rodentia, Carnivora and Artiodactyla.

  9. De novo transcriptome assembly facilitates characterisation of fast-evolving gene families, MHC class I in the bank vole (Myodes glareolus).

    PubMed

    Migalska, M; Sebastian, A; Konczal, M; Kotlík, P; Radwan, J

    2017-04-01

    The major histocompatibility complex (MHC) plays a central role in the adaptive immune response and is the most polymorphic gene family in vertebrates. Although high-throughput sequencing has increasingly been used for genotyping families of co-amplifying MHC genes, its potential to facilitate early steps in the characterisation of MHC variation in nonmodel organism has not been fully explored. In this study we evaluated the usefulness of de novo transcriptome assembly in characterisation of MHC sequence diversity. We found that although de novo transcriptome assembly of MHC I genes does not reconstruct sequences of individual alleles, it does allow the identification of conserved regions for PCR primer design. Using the newly designed primers, we characterised MHC I sequences in the bank vole. Phylogenetic analysis of the partial MHC I coding sequence (2-4 exons) of the bank vole revealed a lack of orthology to MHC I of other Cricetidae, consistent with the high gene turnover of this region. The diversity of expressed alleles was characterised using ultra-deep sequencing of the third exon that codes for the peptide-binding region of the MHC molecule. High allelic diversity was demonstrated, with 72 alleles found in 29 individuals. Interindividual variation in the number of expressed loci was found, with the number of alleles per individual ranging from 5 to 14. Strong signatures of positive selection were found for 8 amino acid sites, most of which are inferred to bind antigens in human MHC, indicating conservation of structure despite rapid sequence evolution.

  10. Pneumocystis and Histoplasma infections in wild animals from the Amazon region of Brazil.

    PubMed

    Lainson, R; Shaw, J J

    1975-01-01

    Routine examination of tissues from wild forest rodents from Amapá, north Brazil, revealed Pneumocystis carinii in lung smears from a newly captured Oryzomys capito (Cricetidae). Acute, fatal infections with this parasite are also recorded in a number of captive "coatimundis", Nasua narica (Carnivora: Procyonidae) and a sloth, Bradypus tridactylus (Edentata). Pneumocystis was also encountered in lung smears from a newly captured and apparently healthy sloth, Choloepus didactylus. The presence of infection in newly captured animals leads us to believe that the fatal, fulminating pneumocystosis seen in the captive Nasua and Bradypus was due to exacerbation of pre-existant infections acquired in their natural forest environment. Pneumocystis carinii is a well known cause of fatal, interstitial plasma-cell pneumonia in human infants and sometimes the weakened adult: the keeping of exotic pets such as the coatimundi is, therefore, not without some hazard in this respect. Histoplasma, another well known pathogen for man, was isolated from 4 rodents, Proechimys guyanensis (Echimyidae), all from virgin forest along the newly opened Trans Amazon Highway, Pará State, and from a single sloth, Choloepus didactylus, from near Belém, Pará. All these animals showed no symptoms of infection: isolation of the parasite was made by the inoculation of laboratory hamsters with saline suspensions of triturated liver and spleen.

  11. Leptospira spp. in rodents and shrews in Germany.

    PubMed

    Mayer-Scholl, Anne; Hammerl, Jens Andre; Schmidt, Sabrina; Ulrich, Rainer G; Pfeffer, Martin; Woll, Dietlinde; Scholz, Holger C; Thomas, Astrid; Nöckler, Karsten

    2014-07-24

    Leptospirosis is an acute, febrile disease occurring in humans and animals worldwide. Leptospira spp. are usually transmitted through direct or indirect contact with the urine of infected reservoir animals. Among wildlife species, rodents act as the most important reservoir for both human and animal infection. To gain a better understanding of the occurrence and distribution of pathogenic leptospires in rodent and shrew populations in Germany, kidney specimens of 2973 animals from 11 of the 16 federal states were examined by PCR. Rodent species captured included five murine species (family Muridae), six vole species (family Cricetidae) and six shrew species (family Soricidae). The most abundantly trapped animals were representatives of the rodent species Apodemus flavicollis, Clethrionomys glareolus and Microtus agrestis. Leptospiral DNA was amplified in 10% of all animals originating from eight of the 11 federal states. The highest carrier rate was found in Microtus spp. (13%), followed by Apodemus spp. (11%) and Clethrionomys spp. (6%). The most common Leptospira genomospecies determined by duplex PCR was L. kirschneri, followed by L. interrogans and L. borgpetersenii; all identified by single locus sequence typing (SLST). Representatives of the shrew species were also carriers of Leptospira spp. In 20% of Crocidura spp. and 6% of the Sorex spp. leptospiral DNA was detected. Here, only the pathogenic genomospecies L. kirschneri was identified.

  12. Discovery of hantaviruses in bats and insectivores and the evolution of the genus Hantavirus.

    PubMed

    Zhang, Yong-Zhen

    2014-07-17

    Hantaviruses are among the most important zoonotic pathogens of humans, causing either hemorrhagic fever with renal syndrome (HFRS) or hantavirus pulmonary syndrome (HPS). From the period 1964-2006 almost all hantaviruses had been identified in rodents, with the exception of Thottapalayam virus (TPMV) isolated from shrews sampled in India. As a consequence, rodents were considered as the natural reservoir hosts. However, over the past seven years, most of the newly found hantavirus genotypes have been from either shrews or moles. Remarkably, in recent years divergent hantaviruses have also been identified in bats sampled from both Africa and Asia. All these data indicate that hantaviruses have a broad range of natural reservoir hosts. Phylogenetic analyses of the available sequences of hantaviruses suggest that hantaviruses might have first appeared in Chiroptera (bats) or Soricomorpha (moles and shrews), before emerging in rodent species. Although rodent hantaviruses cluster according to whether their hosts are members of the Murinae and Cricetidae, the phylogenetic histories of the viruses are not always congruent with those of their hosts, indicating that cross-species transmission events have occurred at all taxonomic levels. In sum, both cross-species transmission and co-divergence have produced the high genetic diversity of hantaviruses described to date.

  13. Morphological diversity and evolution of the spermatozoon in the mouse-related clade of rodents.

    PubMed

    Breed, William G; Leigh, Chris M; Aplin, Ken P; Shahin, Adel A B; Avenant, Nico L

    2014-05-01

    Most species in the three highly speciose families of the mouse-related clade of rodents, the Muridae, Cricetidae, and Nesomyidae (superfamily Muroidea), have a highly complex sperm head in which there is an apical hook but there are few data available for the other related families of these rodents. In the current study, using light and electron microscopies, we investigated the structure of the spermatozoon in representative species of four other families within the mouse-related clade, the Dipodidae, Spalacidae, Pedetidae, and Heteromyidae, that diverged at or near the base of the muroid lineage. Our results indicate that a diverse array of sperm head shapes and tail lengths occurs but none of the species in the families Spalacidae, Dipodidae, or Pedetidae has a sperm head with an apical hook. By contrast, a rostrally extending apical hook is present in spermatozoa of members of the Family Heteromyidae which also invariably have comparatively long sperm tails. These findings suggest that the hook-shaped sperm head in the murid, cricetid, and nesomyid rodents evolved after divergence of this lineage from its common ancestor with the other families of the mouse-related clade, and that separate, and independent, convergent evolution of a similar sperm head form, and long sperm tail, occurred in the Heteromyidae.

  14. Late Oligocene and Early Miocene Muroidea of the Zinda Pir Dome

    PubMed Central

    Lindsay, Everett H.; Flynn, Lawrence J.

    2016-01-01

    A series of Oligocene through Early Miocene terrestrial deposits preserved in the foothills of the Zinda Pir Dome of western Pakistan produce multiple, superposed fossil mammal localities. These include small mammal assemblages that shed light on the evolution of rodent lineages, especially Muroidea, in South Asia. Nine small mammal localities span approximately 28–19 Ma, an interval encompassing the Oligocene–Miocene boundary. The Early Miocene rodent fossil assemblages are dominated by muroid rodents, but muroids are uncommon and archaic in earlier Oligocene horizons. The Zinda Pir sequence includes the evolutionary transition to modern Muroidea at about the Oligocene–Miocene boundary. We review the muroid record for the Zinda Pir Dome, which includes the early radiation of primitive bamboo rats (Rhizomyinae) and early members of the modern muroid radiation, which lie near crown Cricetidae and Muridae. The Zinda Pir record dates diversification of modern muroids in the Indian Subcontintent and establishment by 19 Ma of muroid assemblages characteristic of the later Siwaliks. PMID:26681836

  15. Sex Chromosome Drive

    PubMed Central

    Helleu, Quentin; Gérard, Pierre R.; Montchamp-Moreau, Catherine

    2015-01-01

    Sex chromosome drivers are selfish elements that subvert Mendel's first law of segregation and therefore are overrepresented among the products of meiosis. The sex-biased progeny produced then fuels an extended genetic conflict between the driver and the rest of the genome. Many examples of sex chromosome drive are known, but the occurrence of this phenomenon is probably largely underestimated because of the difficulty to detect it. Remarkably, nearly all sex chromosome drivers are found in two clades, Rodentia and Diptera. Although very little is known about the molecular and cellular mechanisms of drive, epigenetic processes such as chromatin regulation could be involved in many instances. Yet, its evolutionary consequences are far-reaching, from the evolution of mating systems and sex determination to the emergence of new species. PMID:25524548

  16. Molecular Identification of Food Sources in Triatomines in the Brazilian Northeast: Roles of Goats and Rodents in Chagas Disease Epidemiology.

    PubMed

    Valença-Barbosa, Carolina; Fernandes, Fabiano Araújo; Santos, Helena Lucia Carneiro; Sarquis, Otília; Harry, Myriam; Almeida, Carlos Eduardo; Lima, Marli Maria

    2015-11-01

    We used the gut contents of triatomines collected from rural areas of Ceará State, northeastern Brazil, to identify their putative hosts via vertebrate cytb gene sequencing. Successful direct sequencing was obtained for 48% of insects, comprising 50 Triatoma brasiliensis, 7 Triatoma pseudomaculata, and 1 Rhodnius nasutus. Basic local alignment search tool (BLAST) procedure revealed that domestic animals, such as chickens (Gallus gallus) and goats (Capra hircus), are the main food source, including in sylvatic environment. Native hosts were also detected in peridomestic environment such as reptiles (Tropidurus sp. and Iguana iguana) and the Galea spixii (Rodentia: Caviidae). The role of goats and Galea spixii in Chagas disease epidemiology calls for further studies, because these mammals likely link the sylvatic and domestic Trypanosoma cruzi cycles.

  17. The largest fossil rodent

    PubMed Central

    Rinderknecht, Andrés; Blanco, R. Ernesto

    2008-01-01

    The discovery of an exceptionally well-preserved skull permits the description of the new South American fossil species of the rodent, Josephoartigasia monesi sp. nov. (family: Dinomyidae; Rodentia: Hystricognathi: Caviomorpha). This species with estimated body mass of nearly 1000 kg is the largest yet recorded. The skull sheds new light on the anatomy of the extinct giant rodents of the Dinomyidae, which are known mostly from isolated teeth and incomplete mandible remains. The fossil derives from San José Formation, Uruguay, usually assigned to the Pliocene–Pleistocene (4–2 Myr ago), and the proposed palaeoenvironment where this rodent lived was characterized as an estuarine or deltaic system with forest communities. PMID:18198140

  18. Molecular Characterization of Nippostrongylus brasiliensis (Nematoda: Heligmosomatidae) from Mus musculus in India

    PubMed Central

    Chaudhary, Anshu; Goswami, Urvashi; Singh, Hridaya Shanker

    2016-01-01

    Mus musculus (Rodentia: Muridae) has generally been infected with a rodent hookworm Nippostrongylus brasiliensis. In this report, we present morphological and molecular identification of N. brasiliensis by light and scanning electron microscopy and PCR amplification of mitochondrial cytochrome c oxidase subunit 1 (cox1) gene and the protein sequences encoded by cox1 gene, respectively. Despite the use of N. brasiliensis in many biochemistry studies from India, their taxonomic identification was not fully understood, especially at the species level, and no molecular data is available in GenBank from India. Sequence analysis of cox1 gene in this study revealed that the present specimen showed close identity with the same species available in GenBank, confirming that the species is N. brasiliensis. This study represents the first record of molecular identification of N. brasiliensis from India and the protein structure to better understand the comparative phylogenetic characteristics. PMID:28095659

  19. First record of entodiniomorph ciliates in a carnivore, the maned wolf (Chrysocyon brachyurus), from Brazil.

    PubMed

    Vynne, Carly; Kinsella, John M

    2009-06-01

    The entodiniomorph ciliates (Ciliophora: Entodiniomorphida) are endosymbiotes widely found in the intestines of herbivorous mammals. These commensals commonly occur in the Artiodactyla and Perissodactyla and have also been described in the Proboscidea, Primates, Rodentia, and Diprotodontia. This study reports the first finding of a ciliate in a member of order Carnivora, the maned wolf (Chrysocyon brachyurus). Fecal samples from wild and captive maned wolves were screened using ethyl acetate sedimentation. Prevalence in fecal samples collected from free-ranging maned wolves in Brazil was 40% (6 of 15). Fecal samples from two of four captive individuals from the St. Louis Zoo also had the same species of ciliate. The largely frugivorous diet of the maned wolf likely explains the occurrence of these normally herbivore-associated endosymbiotes in a carnivore.

  20. Hepatitis B virus lineages in mammalian hosts: Potential for bidirectional cross-species transmission

    PubMed Central

    Bonvicino, Cibele R; Moreira, Miguel A; Soares, Marcelo A

    2014-01-01

    The hepatitis B virus (HBV) is a cosmopolitan infectious agent currently affecting over 350 million people worldwide, presently accounting for more than two billion infections. In addition to man, other hepatitis virus strains infect species of several mammalian families of the Primates, Rodentia and Chiroptera orders, in addition to birds. The mounting evidence of HBV infection in African, Asian and neotropical primates draws attention to the potential cross-species, zoonotic transmission of these viruses to man. Moreover, recent evidence also suggests the humans may also function as a source of viral infection to other mammals, particularly to domestic animals like poultry and swine. In this review, we list all evidence of HBV and HBV-like infection of nonhuman mammals and discuss their potential roles as donors or recipients of these viruses to humans and to other closely-related species. PMID:24976704

  1. Molecular Identification of Food Sources in Triatomines in the Brazilian Northeast: Roles of Goats and Rodents in Chagas Disease Epidemiology

    PubMed Central

    Valença-Barbosa, Carolina; Fernandes, Fabiano Araújo; Santos, Helena Lucia Carneiro; Sarquis, Otília; Harry, Myriam; Almeida, Carlos Eduardo; Lima, Marli Maria

    2015-01-01

    We used the gut contents of triatomines collected from rural areas of Ceará State, northeastern Brazil, to identify their putative hosts via vertebrate cytb gene sequencing. Successful direct sequencing was obtained for 48% of insects, comprising 50 Triatoma brasiliensis, 7 Triatoma pseudomaculata, and 1 Rhodnius nasutus. Basic local alignment search tool (BLAST) procedure revealed that domestic animals, such as chickens (Gallus gallus) and goats (Capra hircus), are the main food source, including in sylvatic environment. Native hosts were also detected in peridomestic environment such as reptiles (Tropidurus sp. and Iguana iguana) and the Galea spixii (Rodentia: Caviidae). The role of goats and Galea spixii in Chagas disease epidemiology calls for further studies, because these mammals likely link the sylvatic and domestic Trypanosoma cruzi cycles. PMID:26350453

  2. The largest fossil rodent.

    PubMed

    Rinderknecht, Andrés; Blanco, R Ernesto

    2008-04-22

    The discovery of an exceptionally well-preserved skull permits the description of the new South American fossil species of the rodent, Josephoartigasia monesi sp. nov. (family: Dinomyidae; Rodentia: Hystricognathi: Caviomorpha). This species with estimated body mass of nearly 1000kg is the largest yet recorded. The skull sheds new light on the anatomy of the extinct giant rodents of the Dinomyidae, which are known mostly from isolated teeth and incomplete mandible remains. The fossil derives from San José Formation, Uruguay, usually assigned to the Pliocene-Pleistocene (4-2Myr ago), and the proposed palaeoenvironment where this rodent lived was characterized as an estuarine or deltaic system with forest communities.

  3. Distribution and ecology of small mammals in Albania.

    PubMed

    Rogozi, Elton; Bego, Ferdinand; Papa, Anna; Mersini, Kujtim; Bino, Silvia

    2013-01-01

    In order to gain an insight into the population dynamics and habitat preferences of rodents in Albania, small mammals were collected during 2006-2009 in various districts of the country. Of the 15 species of small mammals captured (12 in Rodentia and 3 in Insectivora order), the yellow-necked mouse (Apodemus flavicollis) was the most frequently collected, representing 50% of the 325 small mammals captured, followed by the wood mouse (Apodemus sylvaticus) (20.62%). Apodemus flavicollis is the primary reservoir for Dobrava-Belgrade virus which causes to humans hemorrhagic fever with renal syndrome; the places with A. flavicollis abundance were those with records of the human disease. Knowledge of the reservoir ecology in a country facilitates risk assessments for rodent-borne diseases.

  4. Quinolizidine alkaloids in Ormosia arborea seeds inhibit predation but not hoarding by agoutis (Dasyprocta leporina).

    PubMed

    Guimarães, Paulo Roberto; José, Juliana; Galetti, Mauro; Trigo, José Roberto

    2003-05-01

    Quinolizidine alkaloids (QAs) are secondary compounds found in seeds of many species of plants, possibly protecting them against pathogens and seed predators. QAs were isolated from Ormosia arborea seeds and bioassayed against red-rumped agoutis (Dasyprocta leporina, Rodentia: Caviomorpha) to verify if they inhibit seed predation and food hoarding (seed dispersal). Three treatments were used: (1) seeds of O. arborea, (2) palatable seeds of Mimusops coriacea (Sapotaceae) treated with MeOH, and (3) seeds of M. coriacea treated with QAs dissolved in MeOH in similar concentration to that present in O. arborea. Palatable seeds were significantly more preyed upon than seeds treated with QAs and Ormosia seeds, but QAs did not influence hoarding behavior. QAs in O. arborea may have a strong effect in avoiding seed predation by rodents, without reducing dispersal.

  5. First record of Viannaiidae (Nematoda: Trichostrongylina) in fossorial rodents (Ctenomys spp.) from Central Argentina, with description of a new genus and species.

    PubMed

    Serrano, Paula Carolina; Digiani, María Celina

    2016-09-14

    A new genus and species of Viannaiidae (Trichostrongylina, Heligmosomoidea), Ischilinema baldoi n. gen. et sp. is described parasitizing two species of tuco-tucos, Ctenomys bergi and Ctenomys rosendopascuali (Rodentia, Hystricomorpha, Ctenomyidae) from Córdoba province, Central Argentina. No helminths were previously known from these two host species. The new genus is defined by the following characters: synlophe with 15 continuous ridges subequal in size, presence of left cuticular dilatation, a gap between ridges 1' and 2', bursa asymmetrical with dorsal ray hypertrophied and displaced to the right, and spicules not twisted. This is the first record of Viannaiidae from the Ctenomyidae, enlarging the host range of these parasites to five out of the 12 extant families of caviomorphs.

  6. Complete mitochondrial DNA sequence of the fat dormouse, Glis glis: further evidence of rodent paraphyly.

    PubMed

    Reyes, A; Pesole, G; Saccone, C

    1998-05-01

    The complete mitochondrial genome of the fat dormouse, Glis glis, has been sequenced (16,602 bp). A total of 23 complete mitochondrial mammalian genomes have been taken into account for phylogenetic reconstruction. Phylogenetic analyses were performed with parsimony, distance (stationary Markov model), and maximum-likelihood methods. In all cases, data strongly support the paraphyly of rodents, with dormouse and guinea pig in a different clade from rat and mouse, reaching bootstrap values of 95%. Rodent monophyly and the existence of Glires (Rodentia and Lagomorpha) are weakly supported, with maximum bootstrap values of 11% and 8.6%, respectively. This result agrees with the analyses of isochore patterns in the nuclear genome and the B2 and B2-like retroposons, which show a close relationship between dormice and guinea pigs rather than between dormice and rats and mice.

  7. Karyological and dental identification of Microtus limnophilus in a large focus of alveolar echinococcosis (Gansu, China).

    PubMed

    Courant, F; Brunet-Lecomte, P; Volobouev, V; Chaline, J; Quéré, J P; Nadachowski, A; Montuire, S; Bao, G; Viriot, L; Rausch, R; Erbajeva, M; Shi, D; Giraudoux, P

    1999-06-01

    A study of voles (Arvicolidae, Rodentia) from Gansu (China) designed to identify a potential host of Echinococcus multilocularis, responsible for human alveolar echinococcosis, leads to a general analysis of Microtus limnophilus population karyotypes, M1 of M. oeconomus populations from all of Eurasia and of M. limnophilus of Mongolia. The Microtus of Gansu belonging to the nominal subspecies M. limnophilus limnophilus (2n = 38; NF = 58) differs markedly in size and shape of M1 from the M. limnophilus of Mongolia, which must therefore be considered as a new subspecies M. limnophilus of malygini nov. ssp. (2n = 38; NF = 60) and the M. oeconomus of Mongolia should be ranked as M. oeconomus kharanurensis nov. ssp. (2n = 30; NF = 60).

  8. The role of wild mammals in the maintenance of Rift Valley fever virus.

    PubMed

    Olive, Marie-Marie; Goodman, Steven M; Reynes, Jean-Marc

    2012-04-01

    Rift Valley fever virus (RVFV) is a zoonotic arbovirus affecting primarily domestic ruminants and humans. Numerous vector species are known or implicated in the transmission of RVFV. The role of mammals in the maintenance of RVFV, and the existence of a wild mammal reservoir in the epidemiologic cycle of RVFV, remain largely unknown. Our objective is to present a detailed review of studies undertaken on RVFV, often associated with wild mammals, with the aim of focusing future research on potential reservoirs of the virus. Natural and experimental infections related to RVFV in several mammalian orders, including Artiodactyla, Chiroptera, Rodentia, Primata (nonhuman), Perissodactyla, Carnivora, Proboscidea, Erinaceomorpha, and Lagomorpha, are reviewed; the first four orders have received the greatest attention. The possible role of wild ruminants, especially African buffalo (Syncerus caffer), is also discussed. Conflicting results have been published concerning rodents but, based on the literature, the likely candidate species include the African genera Arvicanthis and Micaelamys and the widely introduced roof rat (Rattus rattus). Members of the orders Chiroptera and Rodentia should receive greater attention associated with new research programs. For the other orders mentioned above, few data are available. We are unaware of any investigation concerning the orders Afrosoricida and Soricomorpha, which are represented in the geographic area of RVFV and can be abundant. As a first step to resolve the question of wild mammals as a reservoir of RVFV, serologic and virologic surveys should be promoted during epizootic periods to document infected wild animals and, in the case of positive results, extended to interepidemic periods to explore the role of wild animals as possible reservoirs.

  9. The hip adductor muscle group in caviomorph rodents: anatomy and homology.

    PubMed

    García-Esponda, César M; Candela, Adriana M

    2015-06-01

    Anatomical comparative studies including myological data of caviomorph rodents are relatively scarce, leading to a lack of use of muscular features in cladistic and morphofunctional analyses. In rodents, the hip adductor muscles constitute an important group of the hindlimb musculature, having an important function during the beginning of the stance phase. These muscles are subdivided in several distinct ways in the different clades of rodents, making the identification of their homologies hard to establish. In this contribution we provide a detailed description of the anatomical variation of the hip adductor muscle group of different genera of caviomorph rodents and identify the homologies of these muscles in the context of Rodentia. On this basis, we identify the characteristic pattern of the hip adductor muscles in Caviomorpha. Our results indicate that caviomorphs present a singular pattern of the hip adductor musculature that distinguishes them from other groups of rodents. They are characterized by having a single m. adductor brevis that includes solely its genicular part. This muscle, together with the m. gracilis, composes a muscular sheet that is medial to all other muscles of the hip adductor group. Both muscles probably have a synergistic action during locomotion, where the m. adductor brevis reinforces the multiple functions of the m. gracilis in caviomorphs. Mapping of analyzed myological characters in the context of Rodentia indicates that several features are recovered as potential synapomorphies of caviomorphs. Thus, analysis of the myological data described here adds to the current knowledge of caviomorph rodents from anatomical and functional points of view, indicating that this group has features that clearly differentiate them from other rodents.

  10. Emergence and Evolution of Zfp36l3

    PubMed Central

    Gingerich, Timothy J.; Stumpo, Deborah J.; Lai, Wi S.; Randall, Thomas A.; Steppan, Scott J.; Blackshear, Perry J.

    2015-01-01

    In most mammals, the Zfp36 gene family consists of three conserved members, with a fourth member, Zfp36l3, present only in rodents. The ZFP36 proteins regulate post-transcriptional gene expression at the level of mRNA stability in organisms from humans to yeasts, and appear to be expressed in all major groups of eukaryotes. In Mus musculus, Zfp36l3 expression is limited to the placenta and yolk sac, and is important for overall fecundity. We sequenced the Zfp36l3 gene from more than 20 representative species, from members of the Muridae, Cricetidae and Nesomyidae families. Zfp36l3 was not present in Dipodidae, or any families that branched earlier, indicating that this gene is exclusive to the Muroidea superfamily. We provide evidence that Zfp36l3 arose by retrotransposition of an mRNA encoded by a related gene, Zfp36l2 into an ancestral rodent X chromosome. Zfp36l3 has evolved rapidly since its origin, and numerous modifications have developed, including variations in start codon utilization, de novo intron formation by mechanisms including a nested retrotransposition, and the insertion of distinct repetitive regions. One of these repeat regions, a long alanine rich-sequence, is responsible for the full-time cytoplasmic localization of Mus musculus ZFP36L3. In contrast, this repeat sequence is lacking in Peromyscus maniculatus ZFP36L3, and this protein contains a novel nuclear export sequence that controls shuttling between the nucleus and cytosol. Zfp36l3 is an example of a recently acquired, rapidly evolving gene, and its various orthologues illustrate several different mechanisms by which new genes emerge and evolve. PMID:26493225

  11. Sexual selection and the adaptive evolution of PKDREJ protein in primates and rodents.

    PubMed

    Vicens, Alberto; Gómez Montoto, Laura; Couso-Ferrer, Francisco; Sutton, Keith A; Roldan, Eduardo R S

    2015-02-01

    PKDREJ is a testis-specific protein thought to be located on the sperm surface. Functional studies in the mouse revealed that loss of PKDREJ has effects on sperm transport and the ability to undergo an induced acrosome reaction. Thus, PKDREJ has been considered a potential target of post-copulatory sexual selection in the form of sperm competition. Proteins involved in reproductive processes often show accelerated evolution. In many cases, this rapid divergence is promoted by positive selection which may be driven, at least in part, by post-copulatory sexual selection. We analysed the evolution of the PKDREJ protein in primates and rodents and assessed whether PKDREJ divergence is associated with testes mass relative to body mass, which is a reliable proxy of sperm competition levels. Evidence of an association between the evolutionary rate of the PKDREJ gene and testes mass relative to body mass was not found in primates. Among rodents, evidence of positive selection was detected in the Pkdrej gene in the family Cricetidae but not in Muridae. We then assessed whether Pkdrej divergence is associated with episodes of sperm competition in these families. We detected a positive significant correlation between the evolutionary rates of Pkdrej and testes mass relative to body mass in cricetids. These findings constitute the first evidence of post-copulatory sexual selection influencing the evolution of a protein that participates in the mechanisms regulating sperm transport and the acrosome reaction, strongly suggesting that positive selection may act on these fertilization steps, leading to advantages in situations of sperm competition.

  12. Sexual selection and the adaptive evolution of PKDREJ protein in primates and rodents

    PubMed Central

    Vicens, Alberto; Gómez Montoto, Laura; Couso-Ferrer, Francisco; Sutton, Keith A.; Roldan, Eduardo R.S.

    2015-01-01

    PKDREJ is a testis-specific protein thought to be located on the sperm surface. Functional studies in the mouse revealed that loss of PKDREJ has effects on sperm transport and the ability to undergo an induced acrosome reaction. Thus, PKDREJ has been considered a potential target of post-copulatory sexual selection in the form of sperm competition. Proteins involved in reproductive processes often show accelerated evolution. In many cases, this rapid divergence is promoted by positive selection which may be driven, at least in part, by post-copulatory sexual selection. We analysed the evolution of the PKDREJ protein in primates and rodents and assessed whether PKDREJ divergence is associated with testes mass relative to body mass, which is a reliable proxy of sperm competition levels. Evidence of an association between the evolutionary rate of the PKDREJ gene and testes mass relative to body mass was not found in primates. Among rodents, evidence of positive selection was detected in the Pkdrej gene in the family Cricetidae but not in Muridae. We then assessed whether Pkdrej divergence is associated with episodes of sperm competition in these families. We detected a positive significant correlation between the evolutionary rates of Pkdrej and testes mass relative to body mass in cricetids. These findings constitute the first evidence of post-copulatory sexual selection influencing the evolution of a protein that participates in the mechanisms regulating sperm transport and the acrosome reaction, strongly suggesting that positive selection may act on these fertilization steps, leading to advantages in situations of sperm competition. PMID:25304980

  13. [Decorative forms of hamsters Phodopus (Mammalia, Cricetinae): an analysis of genetic lines distribution and peculiarities of hair changes].

    PubMed

    Feoktistova, N Iu; Chernova, O F; Meshcherskiĭ, I G

    2012-01-01

    Three species of dwarf hamsters (genus Phodopus, family Cricetidae) inhabit some regions of Russia, Kazakhstan, Mongolia, and China, each having quite extensive range. In recent decades, the dwarf hamsters became widely spread all over the world, initially as laboratory animals and later as popular pets. By now, there is lot of decorative breed lines and colored forms of these animals. Comparison of mtDNA nucleotide sequences of dwarf hamsters acquired in pet shops of some countries in Europe, South-East Asia and North America with distribution of mtDNA haplotypes within natural ranges showed the limitation of decorative line founders' points of origin by one region for each of the species. All haplotypes found in decorative Dzungarian hamsters (Ph. sungorus) purchased ounside Russia coincide with or are significantly close to haplotypes spread in the southern part of West Siberia (Russia) and adjacent regions of Kazakhstan; haplotypes of decorative Campbell's hamster (Ph. campbelli) belong to haplogroup of this species natural populations inhabiting South Tyva (Russia); and all studied decorative Desert hamsters (Ph. roborovskii) had one hapotype specific for South-Eastern Kazakhstan. The review of the history of researches on dwarf hamsters biology allows to determine delivery of hamsters from mentioned regions to scientific laboratories and zoos by certain expeditions and/or researchers. Unlike hamsters with natural hair color, the colored hamsters have no normal hair. Their hair is dull and straggly. The hair differentiation (presence of different hair types and their size characteristics) gets broken and results in deformation, bending, and splitting of the shaft, cracks in cuticle, change of configuration and location of medulla, uneven development of cortex. It is assumed that these destructive changes are associated with genetic characteristics of these hamsters' colored forms.

  14. Prevalence of antibody to hantaviruses in humans and rodents in the Caribbean region of Colombia determined using Araraquara and Maciel virus antigens

    PubMed Central

    Guzmán, Camilo; Mattar, Salim; Levis, Silvana; Pini, Noemí; Figueiredo, Tadeu; Mills, James; Salazar-Bravo, Jorge

    2013-01-01

    We tested sera from 286 agricultural workers and 322 rodents in the department of Córdoba, northeastern Colombia, for antibodies against two hantaviruses. The sera were analysed by indirect ELISA using the lysate of Vero E6 cells infected with Maciel virus (MACV) or the N protein of Araraquara virus (ARAV) as antigens for the detection of antibodies against hantaviruses. Twenty-four human sera were IgG positive using one or both antigens. We detected anti-MACV IgG antibodies in 10 sera (3.5%) and anti-ARAV antibodies in 21 sera (7.34%). Of the 10 samples that were positive for MACV, seven (70%) were cross-reactive with ARAV; seven of the 21 ARAV-positive samples were cross-reactive with MACV. Using an ARAV IgM ELISA, two of the 24 human sera (8.4%) were positive. We captured 322 rodents, including 210 Cricetidae (181 Zygodontomys brevicauda, 28 Oligoryzomys fulvescens and 1 Oecomys trinitatis), six Heteromys anomalus (Heteromyidae), one Proechimys sp. (Echimyidae) and 105 Muridae (34 Rattus rattus and 71 Mus musculus). All rodent sera were negative for both antigens. The 8.4% detection rate of hantavirus antibodies in humans is much higher than previously found in serosurveys in North America, suggesting that rural agricultural workers in northeastern Colombia are frequently exposed to hantaviruses. Our results also indicate that tests conducted with South American hantavirus antigens could have predictive value and could represent a useful alternative for the diagnosis of hantavirus infection in Colombia. PMID:23579795

  15. Function and expression of CD1d and invariant natural killer T-cell receptor in the cotton rat (Sigmodon hispidus).

    PubMed

    Fichtner, Alina Suzann; Paletta, Daniel; Starick, Lisa; Schumann, Richard F; Niewiesk, Stefan; Herrmann, Thomas

    2015-12-01

    The cotton rat (Sigmodon hispidus) belongs to the rodent family of Cricetidae and provides a powerful model to study the pathogenesis of human respiratory viruses and measles virus. Recent studies in other rodent models have suggested a role for invariant natural killer T (iNKT) cells in antiviral immunity and vaccination against respiratory virus infections. Using new experimental tools, we provide the first evidence for a functional CD1d cell molecule (crCD1d) and iNKT T-cell receptor in cotton rats. The crCD1d cDNA sequence was identified and crCD1d transductants showed that monoclonal antibody WTH-2 stains crCD1d as efficiently as mouse or rat CD1d. The expression of crCD1d was clearly weaker for thymocytes and B cells, and higher for T cells, which is different to what is found in murine species. The antigen-presenting capacity of crCD1d was demonstrated with crCD1d-immunoglobulin dimers loaded with the glycolipid PBS57, which bound iNKT T-cell receptors. Evidence for functional cotton rat iNKT cells was provided by detection of interferon-γ and interleukin-4 in cultures of splenocytes stimulated with PBS57 and α-galactosylceramide and by specific staining of about 0·2% of splenocytes with PBS57-loaded crCD1d dimers. Canonical AV14/AJ18 rearrangements were identified and found to contain multiple members of the AV14 (AV11) family. One of them was expressed and found to bind CD1d dimers. In summary, these data provide the first evidence for functional CD1d molecules and iNKT T-cell receptors in cotton rats and provide the tools to analyse them both in the cotton rat model of infectious diseases.

  16. Prevalence of antibody to hantaviruses in humans and rodents in the Caribbean region of Colombia determined using Araraquara and Maciel virus antigens.

    PubMed

    Guzmán, Camilo; Mattar, Salim; Levis, Silvana; Pini, Noemí; Figueiredo, Tadeu; Mills, James; Salazar-Bravo, Jorge

    2013-04-01

    We tested sera from 286 agricultural workers and 322 rodents in the department of Córdoba, northeastern Colombia, for antibodies against two hantaviruses. The sera were analysed by indirect ELISA using the lysate of Vero E6 cells infected with Maciel virus (MACV) or the N protein of Araraquara virus (ARAV) as antigens for the detection of antibodies against hantaviruses. Twenty-four human sera were IgG positive using one or both antigens. We detected anti-MACV IgG antibodies in 10 sera (3.5%) and anti-ARAV antibodies in 21 sera (7.34%). Of the 10 samples that were positive for MACV, seven (70%) were cross-reactive with ARAV; seven of the 21 ARAV-positive samples were cross-reactive with MACV. Using an ARAV IgM ELISA, two of the 24 human sera (8.4%) were positive. We captured 322 rodents, including 210 Cricetidae (181 Zygodontomys brevicauda, 28 Oligoryzomys fulvescens and 1 Oecomys trinitatis), six Heteromys anomalus (Heteromyidae), one Proechimys sp. (Echimyidae) and 105 Muridae (34 Rattus rattus and 71 Mus musculus). All rodent sera were negative for both antigens. The 8.4% detection rate of hantavirus antibodies in humans is much higher than previously found in serosurveys in North America, suggesting that rural agricultural workers in northeastern Colombia are frequently exposed to hantaviruses. Our results also indicate that tests conducted with South American hantavirus antigens could have predictive value and could represent a useful alternative for the diagnosis of hantavirus infection in Colombia.

  17. Hosts, distribution and genetic divergence (16S rDNA) of Amblyomma dubitatum (Acari: Ixodidae).

    PubMed

    Nava, Santiago; Venzal, José M; Labruna, Marcelo B; Mastropaolo, Mariano; González, Enrique M; Mangold, Atilio J; Guglielmone, Alberto A

    2010-08-01

    We supply information about hosts and distribution of Amblyomma dubitatum. In addition, we carry out an analysis of genetic divergence among specimens of A. dubitatum from different localities and with respect to other Neotropical Amblyomma species, using sequences of 16S rDNA gene. Although specimens of A. dubitatum were collected on several mammal species as cattle horse, Tapirus terrestris, Mazama gouazoubira, Tayassu pecari, Sus scrofa, Cerdocyon thous, Myocastor coypus, Allouata caraya, Glossophaga soricina and man, most records of immature and adult stages of A. dubitatum were made on Hydrochoerus hydrochaeris, making this rodent the principal host for all parasitic stages of this ticks. Cricetidae rodents (Lundomys molitor, Scapteromys tumidus), opossums (Didelphis albiventris) and vizcacha (Lagostomus maximus) also were recorded as hosts for immature stages. All findings of A. dubitatum correspond to localities of Argentina, Brazil, Paraguay and Uruguay, and they were concentrated in the Biogeographical provinces of Pampa, Chaco, Cerrado, Brazilian Atlantic Forest, Parana Forest and Araucaria angustifolia Forest. The distribution of A. dubitatum is narrower than that of its principal host, therefore environmental variables rather than hosts determine the distributional ranges of this tick. The intraspecific genetic divergence among 16S rDNA sequences of A. dubitatum ticks collected in different localities from Argentina, Brazil and Uruguay was in all cases lower than 0.8%, whereas the differences with the remaining Amblyomma species included in the analysis were always bigger than 6.8%. Thus, the taxonomic status of A. dubitatum along its distribution appears to be certain at the specific level.

  18. An explanation of the relationship between mass, metabolic rate and characteristic length for placental mammals

    PubMed Central

    2015-01-01

    The Mass, Metabolism and Length Explanation (MMLE) was advanced in 1984 to explain the relationship between metabolic rate and body mass for birds and mammals. This paper reports on a modernized version of MMLE. MMLE deterministically computes the absolute value of Basal Metabolic Rate (BMR) and body mass for individual animals. MMLE is thus distinct from other examinations of these topics that use species-averaged data to estimate the parameters in a statistically best fit power law relationship such as BMR = a(bodymass)b. Beginning with the proposition that BMR is proportional to the number of mitochondria in an animal, two primary equations are derived that compute BMR and body mass as functions of an individual animal’s characteristic length and sturdiness factor. The characteristic length is a measureable skeletal length associated with an animal’s means of propulsion. The sturdiness factor expresses how sturdy or gracile an animal is. Eight other parameters occur in the equations that vary little among animals in the same phylogenetic group. The present paper modernizes MMLE by explicitly treating Froude and Strouhal dynamic similarity of mammals’ skeletal musculature, revising the treatment of BMR and using new data to estimate numerical values for the parameters that occur in the equations. A mass and length data set with 575 entries from the orders Rodentia, Chiroptera, Artiodactyla, Carnivora, Perissodactyla and Proboscidea is used. A BMR and mass data set with 436 entries from the orders Rodentia, Chiroptera, Artiodactyla and Carnivora is also used. With the estimated parameter values MMLE can calculate characteristic length and sturdiness factor values so that every BMR and mass datum from the BMR and mass data set can be computed exactly. Furthermore MMLE can calculate characteristic length and sturdiness factor values so that every body mass and length datum from the mass and length data set can be computed exactly. Whether or not MMLE can

  19. Hibernation does not affect memory retention in bats.

    PubMed

    Ruczynski, Ireneusz; Siemers, Björn M

    2011-02-23

    Long-term memory can be critically important for animals in a variety of contexts, and yet the extreme reduction in body temperature in hibernating animals alters neurochemistry and may therefore impair brain function. Behavioural studies on memory impairment associated with hibernation have been almost exclusively conducted on ground squirrels (Rodentia) and provide conflicting results, including clear evidence for memory loss. Here, we for the first time tested memory retention after hibernation for a vertebrate outside rodents-bats (Chiroptera). In the light of the high mobility, ecology and long life of bats, we hypothesized that maintenance of consolidated memory through hibernation is under strong natural selection. We trained bats to find food in one out of three maze arms. After training, the pre-hibernation performance of all individuals was at 100 per cent correct decisions. After this pre-test, one group of bats was kept, with two interruptions, at 7°C for two months, while the other group was kept under conditions that prevented them from going into hibernation. The hibernated bats performed at the same high level as before hibernation and as the non-hibernated controls. Our data suggest that bats benefit from an as yet unknown neuroprotective mechanism to prevent memory loss in the cold brain.

  20. Seed predation and fruit damage of Solanum lycocarpum (Solanaceae) by rodents in the cerrado of central Brazil

    NASA Astrophysics Data System (ADS)

    Briani and, Denis C., Jr.; Guimarães, Paulo R.

    2007-01-01

    Although neotropical savannas and grasslands, collectively referred to as cerrado, are rich in seed-eating species of rodents, little is known about seed predation and its determinants in this habitat. In this study, we investigated seed predation and damage to fruits of the widespread shrub Solanum lycocarpum. In addition, the influence of two possible determinants (distance from the parental plant and total crop size) on the feeding behaviour of Oryzomys scotti (Rodentia, Sigmodontinae) was also examined. O. scotti were captured more frequently close to the shrubs or on shrub crops, indicating that these rodents were attracted to the shrubs and that seed predation was probably distance-dependent. Moreover, the proportion of damaged fruit on the plant decreased as the total crop size increased; consequently, more productive plants were attacked proportionally less by rodents. This pattern of fruit damage may reflect predator satiation caused by the consumption of a large amount of pulp. Alternatively, secondary metabolites in S. lycocarpum fruits may reduce the pulp consumption per feeding event, thereby limiting the number of fruits damaged.

  1. Characterization of the North American beaver (Castor canadensis) papillomavirus genome.

    PubMed

    Rogovskyy, Artem S; Chen, Zigui; Burk, Robert D; Bankhead, Troy

    2014-01-10

    The papillomaviruses comprise a large group of viruses that cause proliferations of the stratified squamous epithelium of skin and mucosa in a variety of animals. An earlier report identified a novel papillomavirus of the North American beaver, Castor canadensis (CcanPV1) that was associated with cutaneous exophytic lesions. In the current study, we determined the sequence of the complete 7435 basepair genome of CcanPV1. The genome contains an Upstream Regulatory Region located between the end of L1 and the start of E6, and seven canonical papillomavirus open reading frames encoding five early (E6, E7, E1, E2, and E4) and two late (L2 and L1) proteins. No E5 open reading frame was detected. Phylogenetic analysis of the CcanPV1 genome places the virus between the genera Kappapapillomavirus and Mupapillomavirus. Analyses of the papillomavirus genomes detected in different species of the order Rodentia indicate these viruses do not form a monophyletic clade.

  2. Guerrerostrongylus marginalis n. sp. (Trichostrongyloidea: Heligmonellidae) from the Guianan arboreal mouse (Oecomys auyantepui) from French Guiana

    PubMed Central

    2016-01-01

    Based on the number and arrangement of cuticular ridges and configuration of the dorsal ray, nematode specimens collected from the small intestine of eight Guianan arboreal mice, Oecomys auyantepui (Rodentia: Sigmodontinae), in French Guiana are herein described and characterized. Guerrerostrongylus marginalis n. sp. (Heligmosomoidea: Heligmonellidae) shows a synlophe consisting of more than 40 ridges and a unique bursal arrangement with ray 8 (externo-dorsal) extending to the edge of the bursal margin, and appearing more prominent than the dorsal ray. This bursal arrangement is common in members of Hassalstrongylus Durette-Desset, 1971, but uncommon in the other four species in Guerrerostrongylus Sutton & Durette-Desset, 1991. The placement of the new species in Guerrerostrongylus is based on the number and nature of cuticular ridges and the ray arrangement and symmetry of the caudal bursa. Diagnostic characteristics of Guerrerostrongylus marginalis n. sp. include the length of ray 8 relative to bursal margin, the relative size of the spicules and vestibule, and the number of eggs in the uterus. We propose an amendment to the generic diagnosis of Guerrerostrongylus to modify the characters of the long rays 6 (postero-lateral), rays 8 (externo-dorsal), and dorsal ray as diagnostic, since at least ray 6 appears to be short in two different species in the genus, namely G. ulysi Digiani, Notarnicola & Navone, 2012 and G. marginalis n. sp. PMID:26956220

  3. Guerrerostrongylus marginalis n. sp. (Trichostrongyloidea: Heligmonellidae) from the Guianan arboreal mouse (Oecomys auyantepui) from French Guiana.

    PubMed

    Weirich, Jessica M; Catzeflis, François; Jiménez, F Agustín

    2016-01-01

    Based on the number and arrangement of cuticular ridges and configuration of the dorsal ray, nematode specimens collected from the small intestine of eight Guianan arboreal mice, Oecomys auyantepui (Rodentia: Sigmodontinae), in French Guiana are herein described and characterized. Guerrerostrongylus marginalis n. sp. (Heligmosomoidea: Heligmonellidae) shows a synlophe consisting of more than 40 ridges and a unique bursal arrangement with ray 8 (externo-dorsal) extending to the edge of the bursal margin, and appearing more prominent than the dorsal ray. This bursal arrangement is common in members of Hassalstrongylus Durette-Desset, 1971, but uncommon in the other four species in Guerrerostrongylus Sutton & Durette-Desset, 1991. The placement of the new species in Guerrerostrongylus is based on the number and nature of cuticular ridges and the ray arrangement and symmetry of the caudal bursa. Diagnostic characteristics of Guerrerostrongylus marginalis n. sp. include the length of ray 8 relative to bursal margin, the relative size of the spicules and vestibule, and the number of eggs in the uterus. We propose an amendment to the generic diagnosis of Guerrerostrongylus to modify the characters of the long rays 6 (postero-lateral), rays 8 (externo-dorsal), and dorsal ray as diagnostic, since at least ray 6 appears to be short in two different species in the genus, namely G. ulysi Digiani, Notarnicola & Navone, 2012 and G. marginalis n. sp.

  4. Torque patterns of the limbs of small therian mammals during locomotion on flat ground.

    PubMed

    Witte, Hartmut; Biltzinger, Jutta; Hackert, Rémi; Schilling, Nadja; Schmidt, Manuela; Reich, Christian; Fischer, Martin S

    2002-05-01

    In three species of small therian mammals (Scandentia: Tupaia glis, Rodentia: Galea musteloides and Lagomorpha: Ochotona rufescens) the net joint forces and torques acting during stance phase in the four kinematically relevant joints of the forelimbs (scapular pivot, shoulder joint, elbow joint, wrist joint) and the hindlimbs (hip joint, knee joint, ankle joint, intratarsal joint) were determined by inverse dynamic analysis. Kinematics were measured by cineradiography (150 frames s(-1)). Synchronously ground reaction forces were acquired by forceplates. Morphometry of the extremities was performed by a scanning method using structured illumination. The vector sum of ground reaction forces and weight accounts for most of the joint force vector. Inertial effects can be neglected since errors of net joint forces amount at most to 10 %. The general time course of joint torques is comparable for all species in all joints of the forelimb and in the ankle joint. Torques in the intratarsal joints differ between tailed and tail-less species. The torque patterns in the knee and hip joint are unique to each species. For the first time torque patterns are described completely for the forelimb including the scapula as the dominant propulsive segment. The results are compared with the few torque data available for various joints of cats (Felis catus), dogs (Canis lupus f. familiaris), goats (Capra sp.) and horses (Equus przewalskii f. caballus).

  5. New Species of Rotundomys (Cricetinae) from the Late Miocene of Spain and Its Bearing on the Phylogeny of Cricetulodon and Rotundomys

    PubMed Central

    López-Antoñanzas, Raquel; Peláez-Campomanes, Pablo; Álvarez-Sierra, Ángeles

    2014-01-01

    The material of Rotundomys (Rodentia, Cricetinae) from the Late Miocene fossiliferous complex of Cerro de los Batallones (Madrid, Spain) is described and compared with all species currently placed in the genera Rotundomys and Cricetulodon. Both the morphology and size variation encompassed in the collection of specimens from Batallones suggest they belong to a single taxon different from the other known species of these genera. A new species Rotundomys intimus sp. nov. is, therefore, named for it. A cladistic analysis, which is the first ever published concernig these taxa, has been conducted to clear up the phylogenetic position of the new species. Our results suggest that Rotundomys intimus sp. nov. inserts between R. mundi and R. sabatieri as a relatively primitive taxon inside the clade Rotundomys. The new taxon is more derived than R. mundi in having a transversal connection between the metalophulid and the anterolophulid on some m1 but more primitive than R. sabatieri and the most evolved species of Rotundomys (R. montisrotuni +R.bressanus) in its less developed lophodonty showing distinct cusps, shallower valleys, and the presence of a subdivided anteroloph on the M1. The species of Cricetulodon do not form a monophyletic group. As a member of Rotundomys, Rotundomys intimus sp. nov. is more derived than all of these taxa in its greater lophodonty and the complete loss of the anterior protolophule, mesolophs, and mesolophids. PMID:25389967

  6. Microsatellite-encoded domain in rodent Sry functions as a genetic capacitor to enable the rapid evolution of biological novelty.

    PubMed

    Chen, Yen-Shan; Racca, Joseph D; Sequeira, Paul W; Phillips, Nelson B; Weiss, Michael A

    2013-08-13

    The male program of therian mammals is determined by Sry, a transcription factor encoded by the Y chromosome. Specific DNA binding is mediated by a high mobility group (HMG) box. Expression of Sry in the gonadal ridge activates a Sox9-dependent gene regulatory network leading to testis formation. A subset of Sry alleles in superfamily Muroidea (order Rodentia) is remarkable for insertion of an unstable DNA microsatellite, most commonly encoding (as in mice) a CAG repeat-associated glutamine-rich domain. We provide evidence, based on an embryonic pre-Sertoli cell line, that this domain functions at a threshold length as a genetic capacitor to facilitate accumulation of variation elsewhere in the protein, including the HMG box. The glutamine-rich domain compensates for otherwise deleterious substitutions in the box and absence of nonbox phosphorylation sites to ensure occupancy of DNA target sites. Such compensation enables activation of a male transcriptional program despite perturbations to the box. Whereas human SRY requires nucleocytoplasmic shuttling and coupled phosphorylation, mouse Sry contains a defective nuclear export signal analogous to a variant human SRY associated with inherited sex reversal. We propose that the rodent glutamine-rich domain has (i) fostered accumulation of cryptic intragenic variation and (ii) enabled unmasking of such variation due to DNA replicative slippage. This model highlights genomic contingency as a source of protein novelty at the edge of developmental ambiguity and may underlie emergence of non-Sry-dependent sex determination in the radiation of Muroidea.

  7. Wild and synanthropic reservoirs of Leishmania species in the Americas

    PubMed Central

    Roque, André Luiz R.; Jansen, Ana Maria

    2014-01-01

    The definition of a reservoir has changed significantly in the last century, making it necessary to study zoonosis from a broader perspective. One important example is that of Leishmania, zoonotic multi-host parasites maintained by several mammal species in nature. The magnitude of the health problem represented by leishmaniasis combined with the complexity of its epidemiology make it necessary to clarify all of the links in transmission net, including non-human mammalian hosts, to develop effective control strategies. Although some studies have described dozens of species infected with these parasites, only a minority have related their findings to the ecological scenario to indicate a possible role of that host in parasite maintenance and transmission. Currently, it is accepted that a reservoir may be one or a complex of species responsible for maintaining the parasite in nature. A reservoir system should be considered unique on a given spatiotemporal scale. In fact, the transmission of Leishmania species in the wild still represents an complex enzootic “puzzle”, as several links have not been identified. This review presents the mammalian species known to be infected with Leishmania spp. in the Americas, highlighting those that are able to maintain and act as a source of the parasite in nature (and are thus considered potential reservoirs). These host/reservoirs are presented separately in each of seven mammal orders – Marsupialia, Cingulata, Pilosa, Rodentia, Primata, Carnivora, and Chiroptera – responsible for maintaining Leishmania species in the wild. PMID:25426421

  8. Identification of potential hosts and vectors of scrub typhus and tick-borne spotted fever group rickettsiae in eastern Taiwan.

    PubMed

    Kuo, C C; Huang, C L; Wang, H C

    2011-06-01

    Scrub typhus and tick-borne spotted fever group (SFG) rickettsioses are transmitted by chiggers (larval trombiculid mites) and hard ticks, respectively. We assessed exposure to these disease vectors by extensively sampling both chiggers and ticks and their small mammal hosts in eastern Taiwan during 2007 and 2008. The striped field mouse Apodemus agrarius Pallas (Rodentia: Muridae) was the most common of the small mammals (36.1% of 1393 captures) and presented the highest rate of infestation with both chiggers (47.8% of 110 760) and ticks (78.1% of 1431). Leptotrombidium imphalum Vercammen-Grandjean & Langston (Trombidiformes: Trombiculidae) and immature Rhipicephalus haemaphysaloides Supino (Ixodida: Ixodidae) were the most abundant chiggers (84.5%) and ticks (>99%) identified, respectively. Immunofluorescent antibody assay revealed high seropositive rates of rodents against Orientia tsutsugamushi Hyashi (Rickettsiales: Rickettsiaceae), the aetiological agent of scrub typhus (70.0% of 437 rodents), and tick-borne SFG rickettsiae (91.9% of 418 rodents). The current study represents a first step towards elucidating the potential hosts and vectors in the enzootic transmission of O. tsutsugamushi and tick-borne SFG rickettsiae in Taiwan. Further studies should focus on characterizing pathogens in L. imphalum and R. haemaphysaloides, as well as the proclivity of both vectors to humans. Uncovering the main hosts of adult ticks is also critical for the prevention of SFG rickettsial infections.

  9. Genome sizes in afrotheria, xenarthra, euarchontoglires, and laurasiatheria.

    PubMed

    Redi, C A; Zacharias, H; Merani, S; Oliveira-Miranda, M; Aguilera, M; Zuccotti, M; Garagna, S; Capanna, E

    2005-01-01

    Topical literature and Web site databases provide genome sizes for approximately 4,000 animal species, invertebrates and vertebrates, 330 of which are mammals. We provide the genome size for 67 mammalian species, including 51 never reported before. Knowledge of genome size facilitates sequencing projects. The data presented here encompassed 5 Metatheria (order Didelphimorphia) and 62 Eutheria: 15 Xenarthra, 24 Euarchontoglires (Rodentia), as well as 23 Laurasiatheria (22 Chiroptera and 1 species from Perissodactyla). Already available karyotypes supplement the haploid nuclear DNA contents of the respective species. Thus, we established the first comprehensive set of genome size measurements for 15 Xenarthra species (armadillos) and for 12 house-mouse species; each group was previously represented by only one species. The Xenarthra exhibited much larger genomes than the modal 3 pg DNA known for mammals. Within the genus Mus, genome sizes varied between 2.98 pg and 3.68 pg. The 22 bat species we measured support the low 2.63 pg modal value for Chiroptera. In general, the genomes of Euarchontoglires and Laurasiatheria were found being smaller than those of (Afrotheria and) Xenarthra. Interspecific variation in genome sizes is discussed with particular attention to repetitive elements, which probably promoted the adaptation of extant mammals to their environment.

  10. The ecology of the Trypanosoma cruzi transmission cycle: Dispersion of zymodeme 3 (Z3) in wild hosts from Brazilian biomes.

    PubMed

    Lisboa, Cristiane Varella; Xavier, Samanta Cristina das Chagas; Herrera, Heitor Miraglia; Jansen, Ana Maria

    2009-10-28

    Two main genotypes in Trypanosoma cruzi subpopulations can be distinguished by PCR amplification of sequences from the mini-exon gene non-transcribed spacer, respectively, T. cruzi I (TCI) and T. cruzi II (TCII). This technique is also capable of distinguishing a third assemblage of subpopulations that do not fit in these genotypes and that remain known as zymodeme Z3 (Z3). The distribution pattern as well as the mammalian host range of this latter T. cruzi sublineage still remains unclear. Thus, the intention of our study was to increase the information regarding these aspects. The mini-exon analysis of T. cruzi isolates obtained from sylvatic animals in the Amazon Forest, Atlantic Rainforest, Caatinga and Pantanal showed that prevalence of the Z3 subpopulation in nature was low (15 out of 225 isolates, corresponding to 7%). A higher prevalence of Z3 was observed in the Caatinga (15%) and the Pantanal (12%). Infection by Z3 was observed in mammalian hosts included in Carnivora, Chiroptera, Didelphimorphia, Rodentia and Xernathra. The T. cruzi Z3 subpopulation was observed also in mixed infections (33%) with TCI (n=2) and TCII (n=3). These results demonstrate that T. cruzi Z3 displays a wider distribution and host range than formerly understood as it has been demonstrated to be able infect species included in five orders of mammalian host species dispersed through all forest strata of the four Brazilian biomes evaluated.

  11. Evolution of genome organizations of squirrels (Sciuridae) revealed by cross-species chromosome painting.

    PubMed

    Li, Tangliang; O'Brien, Patricia C M; Biltueva, Larisa; Fu, Beiyuan; Wang, Jinhuan; Nie, Wenhui; Ferguson-Smith, Malcolm A; Graphodatsky, Alexander S; Yang, Fengtang

    2004-01-01

    With complete sets of chromosome-specific painting probes derived from flow-sorted chromosomes of human and grey squirrel (Sciurus carolinensis), the whole genome homologies between human and representatives of tree squirrels (Sciurus carolinensis, Callosciurus erythraeus), flying squirrels (Petaurista albiventer) and chipmunks (Tamias sibiricus) have been defined by cross-species chromosome painting. The results show that, unlike the highly rearranged karyotypes of mouse and rat, the karyotypes of squirrels are highly conserved. Two methods have been used to reconstruct the genome phylogeny of squirrels with the laboratory rabbit (Oryctolagus cuniculus) as the out-group: (1) phylogenetic analysis by parsimony using chromosomal characters identified by comparative cytogenetic approaches; (2) mapping the genome rearrangements onto recently published sequence-based molecular trees. Our chromosome painting results, in combination with molecular data, show that flying squirrels are phylogenetically close to New World tree squirrels. Chromosome painting and G-banding comparisons place chipmunks (Tamias sibiricus ), with a derived karyotype, outside the clade comprising tree and flying squirrels. The superorder Glires (orde Rodentia + order Lagomorpha) is firmly supported by two conserved syntenic associations between human chromosomes 1 and 10p homologues, and between 9 and 11 homologues.

  12. Ecological diversity of Trypanosoma cruzi transmission in the Amazon basin. The main scenaries in the Brazilian Amazon.

    PubMed

    Coura, J R; Junqueira, A C V

    2015-11-01

    The ecological diversity of Trypanosoma cruzi transmission in the Brazilian Amazon region is directly interlinked with the parasite's extensive reservoir, composed of 33 species of wild mammals within the following orders: Marsupialia, Chiroptera, Rodentia, Xenarthra, Carnivora and Primates; and of 16 species of wild triatomines, of which ten may be infected with T. cruzi. Four scenarios for the diversity of T. cruzi transmission in the Brazilian Amazon region are evident: (i) T. cruzi transmission between vectors and wild mammals, which is characterized as a wild enzooty encompassing the entire Amazon basin; (ii) accidental T. cruzi transmission from vectors and wild mammals to humans, when they invade the wild ecotope or when these vectors and wild mammals invade human homes; (iii) occupational Chagas disease among piassava (Leopoldinia piassaba) palm fiber gatherers, transmitted by the vector Rhodnius brethesi, for which these palm trees are the specific ecotope; (IV) oral T. cruzi transmission to humans through food contamination, particularly in juices from plants such as assai, which today is considered to be endemic in the Brazilian Amazon region, with more than 1500 cases notified.

  13. Abrocomaphthirus hoplai, a new genus and species of sucking louse from Chile and its relevance to zoogeography.

    PubMed

    Durden, L A; Webb, J P

    1999-10-01

    Both sexes of Abrocomaphthirus hoplai, new genus and new species (Anoplura: Polyplacidae), are described and illustrated. The endemic Chilean chinchilla rat Abrocoma bennetti Waterhouse (Rodentia: Abrocomidae) is the type host. The definition of the family Polyplacidae is amended to accommodate the new genus. Polyplax longa (Werneck), also referred to in the literature as Neohaematopinus longus Werneck, is reassigned to Abrocomaphthirus. The host of A. longus comb.n., is Abrocoma cinerea Thomas, another chinchilla rat, which inhabits parts of Argentina, Bolivia, Chile and Peru. The erection of Abrocomaphthirus as a distinct genus has important zoogeographical and evolutionary implications. The tenuous anomaly of P. longa being the sole native representative of the genus Polyplax in South America, possibly with African affinities, is now refuted. Instead, partial colonization of the neotropics by native species of both Polyplax and Neohaematopinus appears to have been relatively recent and from North America. The phylogenetic affinities of Abrocomaphthirus are unknown, but it appears to be closely related to other, more ancient, native South American polyplacid louse genera, such as Cuyana, Eulinognathus, Galeophthirus, and Lagidiophthirus. Arguments are presented in support of an ancestral zoogeographical link to Africa for these louse genera.

  14. Molecular and Paleontological Evidence for a Post-Cretaceous Origin of Rodents

    PubMed Central

    Wu, Shaoyuan; Wu, Wenyu; Zhang, Fuchun; Ye, Jie; Ni, Xijun; Sun, Jimin; Edwards, Scott V.; Meng, Jin; Organ, Chris L.

    2012-01-01

    The timing of the origin and diversification of rodents remains controversial, due to conflicting results from molecular clocks and paleontological data. The fossil record tends to support an early Cenozoic origin of crown-group rodents. In contrast, most molecular studies place the origin and initial diversification of crown-Rodentia deep in the Cretaceous, although some molecular analyses have recovered estimated divergence times that are more compatible with the fossil record. Here we attempt to resolve this conflict by carrying out a molecular clock investigation based on a nine-gene sequence dataset and a novel set of seven fossil constraints, including two new rodent records (the earliest known representatives of Cardiocraniinae and Dipodinae). Our results indicate that rodents originated around 61.7–62.4 Ma, shortly after the Cretaceous/Paleogene (K/Pg) boundary, and diversified at the intraordinal level around 57.7–58.9 Ma. These estimates are broadly consistent with the paleontological record, but challenge previous molecular studies that place the origin and early diversification of rodents in the Cretaceous. This study demonstrates that, with reliable fossil constraints, the incompatibility between paleontological and molecular estimates of rodent divergence times can be eliminated using currently available tools and genetic markers. Similar conflicts between molecular and paleontological evidence bedevil attempts to establish the origination times of other placental groups. The example of the present study suggests that more reliable fossil calibration points may represent the key to resolving these controversies. PMID:23071573

  15. Cellular scaling rules for rodent brains

    PubMed Central

    Herculano-Houzel, Suzana; Mota, Bruno; Lent, Roberto

    2006-01-01

    How do cell number and size determine brain size? Here, we show that, in the order Rodentia, increased size of the cerebral cortex, cerebellum, and remaining areas across six species is achieved through greater numbers of neurons of larger size, and much greater numbers of nonneuronal cells of roughly invariant size, such that the ratio between total neuronal and nonneuronal mass remains constant across species. Although relative cerebellar size remains stable among rodents, the number of cerebellar neurons increases with brain size more rapidly than in the cortex, such that the cerebellar fraction of total brain neurons increases with brain size. In contrast, although the relative cortical size increases with total brain size, the cortical fraction of total brain neurons remains constant. We propose that the faster increase in average neuronal size in the cerebral cortex than in the cerebellum as these structures gain neurons and the rapidly increasing glial numbers that generate glial mass to match total neuronal mass at a fixed glia/neuron total mass ratio are fundamental cellular constraints that lead to the relative expansion of cerebral cortical volume across species. PMID:16880386

  16. Reproductive delays in mammals: an unexplored avenue for post-copulatory sexual selection.

    PubMed

    Orr, Teri J; Zuk, Marlene

    2014-11-01

    Numerous mammalian taxa exhibit reproductive delays, pauses in reproduction that occur between mating and fertilization, between fertilization and implantation of the embryo, or after an embryo has implanted. Of the 27 mammalian orders, 9 are known to exhibit reproductive delays, including Diptrotodontia, Dasyuromorphia, Eulipotyphyta, Cingulata, Carnivora, Rodentia, Chiroptera, Lagomorpha and Cetartiodactyla. Most researchers interested in delays have focused on their evolutionary origins. However, the consequences of these delays have not been considered fully. Given the lengthening of the period over which reproduction occurs, it is possible that this unique aspect of reproduction facilitates post-copulatory sexual selection. When considered in the context of sexual selection, delays may allow sperm competition and female manipulation of fertilization (cryptic female choice) as well as other post-copulatory processes. We investigate the potential for reproductive delays to facilitate post-copulatory sexual selection and suggest avenues for research that may further our knowledge of sexual selection. We also provide a general review of reproductive delays in mammals.

  17. Hystricognathy vs Sciurognathy in the Rodent Jaw: A New Morphometric Assessment of Hystricognathy Applied to the Living Fossil Laonastes (Diatomyidae)

    PubMed Central

    Hautier, Lionel; Lebrun, Renaud; Saksiri, Soonchan; Michaux, Jacques; Vianey-Liaud, Monique; Marivaux, Laurent

    2011-01-01

    While exceptional for an intense diversification of lineages, the evolutionary history of the order Rodentia comprises only a limited number of morphological morphotypes for the mandible. This situation could partly explain the intense debates about the taxonomic position of the latest described member of this clade, the Laotian rock rat Laonastes aenigmamus (Diatomyidae). This discovery has re-launched the debate on the definition of the Hystricognathi suborder identified using the angle of the jaw relative to the plane of the incisors. Our study aims to end this ambiguity. For clarity, it became necessary to revisit the entire morphological diversity of the mandible in extant and extinct rodents. However, current and past rodent diversity brings out the limitations of the qualitative descriptive approach and highlights the need for a quantitative approach. Here, we present the first descriptive comparison of the masticatory apparatus within the Ctenohystrica clade, in combining classic comparative anatomy with morphometrical methods. First, we quantified the shape of the mandible in rodents using 3D landmarks. Then, the analysis of osteological features was compared to myological features in order to understand the biomechanical origin of this morphological diversity. Among the morphological variation observed, the mandible of Laonastes aenigmamus displays an intermediate association of features that could be considered neither as sciurognathous nor as hystricognathous. PMID:21490933

  18. Differentiated evolutionary relationships among chordates from comparative alignments of multiple sequences of MyoD and MyoG myogenic regulatory factors.

    PubMed

    Oliani, L C; Lidani, K C F; Gabriel, J E

    2015-10-16

    MyoD and MyoG are transcription factors that have essential roles in myogenic lineage determination and muscle differentiation. The purpose of this study was to compare multiple amino acid sequences of myogenic regulatory proteins to infer evolutionary relationships among chordates. Protein sequences from Mus musculus (P10085 and P12979), human Homo sapiens (P15172 and P15173), bovine Bos taurus (Q7YS82 and Q7YS81), wild pig Sus scrofa (P49811 and P49812), quail Coturnix coturnix (P21572 and P34060), chicken Gallus gallus (P16075 and P17920), rat Rattus norvegicus (Q02346 and P20428), domestic water buffalo Bubalus bubalis (D2SP11 and A7L034), and sheep Ovis aries (Q90477 and D3YKV7) were searched from a non-redundant protein sequence database UniProtKB/Swiss-Prot, and subsequently analyzed using the Mega6.0 software. MyoD evolutionary analyses revealed the presence of three main clusters with all mammals branched in one cluster, members of the order Rodentia (mouse and rat) in a second branch linked to the first, and birds of the order Galliformes (chicken and quail) remaining isolated in a third. MyoG evolutionary analyses aligned sequences in two main clusters, all mammalian specimens grouped in different sub-branches, and birds clustered in a second branch. These analyses suggest that the evolution of MyoD and MyoG was driven by different pathways.

  19. Unexpected primitive rodents in the Quaternary of Argentina

    NASA Astrophysics Data System (ADS)

    Vucetich, María G.; Vieytes, Emma C.; Verzi, Diego H.; Noriega, Jorge I.; Tonni, Eduardo P.

    2005-10-01

    This article describes the first fossils recorded in the Hernandarias Formation (Pleistocene) in Entre Ríos province (eastern Argentina). They are represented by three teeth assigned to the caviomorph rodents (Rodentia, Mammalia) Aenigmys diamantensis gen. et sp. nov. and Eumysops. To establish the phylogenetic affinities of the two most enigmatic teeth, their enamel microstructure was studied. Aenigmys diamantensis is considered the most primitive taxon of a clade formed by Dinomyidae-Neoepiblemidae-Heptaxodontidae. Evidence of the close relationships among these families also is presented herein. The new fossils reinforce previous hypotheses about the survival of primitive Brazilian taxa after their extinction in the Pampas and Patagonia of southern South America. They also show that the diversity of caviomorph rodents during the Quaternary was greater than supposed and that an important Quaternary extinction, not previously detected, affected several lineages. With the available evidence, it is not possible to determine if these rodents indicate a warm pulse or a particular biogeographic situation in Entre Ríos.

  20. Social Structure Predicts Genital Morphology in African Mole-Rats

    PubMed Central

    Seney, Marianne L.; Kelly, Diane A.; Goldman, Bruce D.; Šumbera, Radim; Forger, Nancy G.

    2009-01-01

    Background African mole-rats (Bathyergidae, Rodentia) exhibit a wide range of social structures, from solitary to eusocial. We previously found a lack of sex differences in the external genitalia and morphology of the perineal muscles associated with the phallus in the eusocial naked mole-rat. This was quite surprising, as the external genitalia and perineal muscles are sexually dimorphic in all other mammals examined. We hypothesized that the lack of sex differences in naked mole-rats might be related to their unusual social structure. Methodology/Principal Findings We compared the genitalia and perineal muscles in three African mole-rat species: the naked mole-rat, the solitary silvery mole-rat, and the Damaraland mole-rat, a species considered to be eusocial, but with less reproductive skew than naked mole-rats. Our findings support a relationship between social structure, mating system, and sexual differentiation. Naked mole-rats lack sex differences in genitalia and perineal morphology, silvery mole-rats exhibit sex differences, and Damaraland mole-rats are intermediate. Conclusions/Significance The lack of sex differences in naked mole-rats is not an attribute of all African mole-rats, but appears to have evolved in relation to their unusual social structure and reproductive biology. PMID:19829697

  1. Frequent expansions of the bitter taste receptor gene repertoire during evolution of mammals in the Euarchontoglires clade.

    PubMed

    Hayakawa, Takashi; Suzuki-Hashido, Nami; Matsui, Atsushi; Go, Yasuhiro

    2014-08-01

    Genome studies of mammals in the superorder Euarchontoglires (a clade that comprises the orders Primates, Dermoptera, Scandentia, Rodentia, and Lagomorpha) are important for understanding the biological features of humans, particularly studies of medical model animals such as macaques and mice. Furthermore, the dynamic ecoevolutionary signatures of Euarchontoglires genomes may be discovered because many species in this clade are characterized by their successful adaptive radiation to various ecological niches. In this study, we investigated the evolutionary trajectory of bitter taste receptor genes (TAS2Rs) in 28 Euarchontoglires species based on homology searches of 39 whole-genome assemblies. The Euarchontoglires species possessed variable numbers of intact TAS2Rs, which ranged from 16 to 40, and their last common ancestor had at least 26 intact TAS2Rs. The gene tree showed that there have been at least seven lineage-specific events involving massive gene duplications. Gene duplications were particularly evident in the ancestral branches of anthropoids (the anthropoid cluster), which may have promoted the adaptive evolution of anthropoid characteristics, such as a trade-off between olfaction and other senses and the development of herbivorous characteristics. Subsequent whole-gene deletions of anthropoid cluster TAS2Rs in hominoid species suggest ongoing ectopic homologous recombination in the anthropoid cluster. These findings provide insights into the roles of adaptive sensory evolution in various ecological niches and important clues related to the molecular mechanisms that underlie taste diversity in Euarchontoglires mammalian species, including humans.

  2. Checklist of helminths found in Patagonian wild mammals.

    PubMed

    Fugassa, Martin H

    2015-09-03

    Using available reports, a checklist of the recorded helminth parasites of wild mammals from Patagonia was generated. Records of parasites found in Patagonia were included, together with records from mammals in áreas outside of Patagonia but whose range extends into Patagonia. Information about the host, localities, and references were also included. A total of 1323 records (224 Cestoda, 167 Trematoda, 894 Nematoda, 34 Acanthocephala, and 4 Pentastomida) belonging to 452 helminth species (77 Cestoda, 76 Trematoda, 277 Nematoda, 21 Acanthocephala, and 1 Pentastomida) found in 57 native mammals (22 Rodentia, 4 Didelphimorphia 1 Microbiotheria, 7 Chiroptera, 5 Cingulata, and 13 Carnivora) were listed. However, only 10.6 % of the reports were conducted on samples from Patagonia and corresponded to 25% of mammals in the region. In addition, many studies were made on a few species and, for example, 52% corresponded to studies made on Lama guanicoe. This suggests the need to increase efforts to know the parasitic fauna in a peculiar region as is the Patagonia. This is the first compilation of the helminth parasites of mammals in Argentine Patagonia and is important for parasitological and paleoparasitological studies.

  3. Higher taxonomic relationships among extant mammals based on morphology, with selected comparisons of results from molecular data.

    PubMed

    Shoshani, J; McKenna, M C

    1998-06-01

    Until a few decades ago, phylogenetic relationships among placental orders were ambiguous and usually depicted to radiate as an unresolved "bush." Resolution of this bush by various workers has been progressing slowly, but with promising results corroborated by nondental, dental, and molecular characters. In this study we continue to seek resolution. A total of 258 nondental and 2 dental characters was analyzed by PAUP and MacClade on 39 vertebrate taxa (3 reptiles, 1 nonmammalian therapsid, and 35 mammals; 20 of the mammals are extant and 15 are extinct) to study higher taxonomic relationships with emphasis on Placentalia (Eutheria). About two-thirds of the characters are osteological, the rest concern soft tissues, including myological but excluding molecular characters (most are our data, the rest are from the literature). Cladistic analysis included all 39 taxa (fossil taxa help to evaluate polarities of characters) and all characters were given equal weight. Extant Mammalia are divided into Prototheria and Theria, the latter into Marsupialia and Placentalia. Placentalia comprises Xenarthra and Epitheria. Within Epitheria, Lipotyphla and Preptotheria (emended) are sister-taxa. Preptotherian taxa group into: ungulate-related taxa and various nonungulates. The former include Carnivora, Pholidota, Tubulidentata, Artiodactyla, Cetacea, Perissodactyla, Hyracoidea, Proboscidea, and Sirenia. A possible association to embrace Lagomorpha, Rodentia, Macroscelidea, Scandentia, Primates, Chiroptera, and Dermoptera is suggested. Significant differences between our findings and those of recent investigators include the dissociation of Pholidota from Xenarthra and the plesiomorphous position of Lipotyphla within Epitheria. Congruence between morphological and molecular results is closer than previously reported.

  4. DNA-based and geometric morphometric analysis to validate species designation: a case study of the subterranean rodent Ctenomys bicolor.

    PubMed

    Stolz, J F B; Gonçalves, G L; Leipnitz, L; Freitas, T R O

    2013-10-25

    The genus Ctenomys (Rodentia: Ctenomyidae) shows several taxonomic inconsistencies. In this study, we used an integrative approach including DNA sequences, karyotypes, and geometric morphometrics to evaluate the taxonomic validity of a nominal species, Ctenomys bicolor, which was described based on only one specimen in 1912 by Miranda Ribeiro, and since then neglected. We sampled near the type locality assigned to this species and collected 10 specimens. A total of 820 base pairs of the cytochrome b gene were sequenced and analyzed together with nine other species and four morphotypes obtained from GenBank. Bayesian analyses showed that C. bicolor is monophyletic and related to the Bolivian-Matogrossense group, a clade that originated about 3 mya. We compared the cranial shape through morphometric geometrics of C. bicolor, including the specimen originally sampled in 1912, with other species representative of the same phylogenetic group (C. boliviensis and C. steinbachi). C. bicolor shows unique skull traits that distinguish it from all other currently known taxa. Our findings confirm that the specimen collected by Miranda Ribeiro is a valid species, and improve the knowledge about Ctenomys in the Amazon region.

  5. A Revised Checklist of Chigger Mites (Acari: Trombiculidae) From Thailand, with the Description of Three New Species.

    PubMed

    Chaisiri, Kittipong; Stekolnikov, Alexandr A; Makepeace, Benjamin L; Morand, Serge

    2016-03-01

    Chigger mites of Thailand were studied on the basis of larvae collected from 19 small mammal species (17 species of Rodentia, 1 species of Erinaceomorpha, and 1 species of Scandentia) and revision of published data. Samples of 38 trombiculid species were collected from 11 provinces. Three new species were described: Trombiculindus kosapani sp. nov., Helenicula naresuani sp. nov., and Walchia chavali sp. nov. Ten species were recorded in Thailand for the first time: Leptotrombidium sialkotense Vercammen-Grandjean and Langston, 1976; Leptotrombidium subangulare Wen and Xiang, 1984; Leptotrombidium tenompaki Stekolnikov, 2013; Leptotrombidium turdicola Vercammen-Grandjean and Langston, 1976; Leptotrombidium yunlingense Yu, Yang, Zhang and Hu, 1981; Lorillatum hekouensis Yu, Chen and Lin, 1996; Helenicula pilosa (Abonnenc and Taufflieb, 1957); Gahrliepia xiaowoi Wen and Xiang, 1984; Walchia minuscuta Chen, 1978; and Walchia ventralis (Womersley, 1952). In all, 99 chigger mite species were considered; the presence of 93 species was established in Thailand by original data or properly documented records in the scientific literature. Evidence for 64 species records of 147 from a previous checklist of Thai chiggers (Tanskul 1993) remains unknown. Distribution of chigger species by geographical regions of Thailand is discussed.

  6. More novel hantaviruses and diversifying reservoir hosts--time for development of reservoir-derived cell culture models?

    PubMed

    Eckerle, Isabella; Lenk, Matthias; Ulrich, Rainer G

    2014-02-26

    Due to novel, improved and high-throughput detection methods, there is a plethora of newly identified viruses within the genus Hantavirus. Furthermore, reservoir host species are increasingly recognized besides representatives of the order Rodentia, now including members of the mammalian orders Soricomorpha/Eulipotyphla and Chiroptera. Despite the great interest created by emerging zoonotic viruses, there is still a gross lack of in vitro models, which reflect the exclusive host adaptation of most zoonotic viruses. The usually narrow host range and genetic diversity of hantaviruses make them an exciting candidate for studying virus-host interactions on a cellular level. To do so, well-characterized reservoir cell lines covering a wide range of bat, insectivore and rodent species are essential. Most currently available cell culture models display a heterologous virus-host relationship and are therefore only of limited value. Here, we review the recently established approaches to generate reservoir-derived cell culture models for the in vitro study of virus-host interactions. These successfully used model systems almost exclusively originate from bats and bat-borne viruses other than hantaviruses. Therefore we propose a parallel approach for research on rodent- and insectivore-borne hantaviruses, taking the generation of novel rodent and insectivore cell lines from wildlife species into account. These cell lines would be also valuable for studies on further rodent-borne viruses, such as orthopox- and arenaviruses.

  7. New Aspidoderidae species parasite of Didelphis aurita (Mammalia: Didelphidae): a light and scanning electron microscopy approach.

    PubMed

    Chagas-Moutinho, V A; Sant'anna, V; Oliveira-Menezes, A; De Souza, W

    2014-02-01

    Nematodes of the family Aspidoderidae (Nematoda: Heterakoidea) Skrjabin and Schikobalova, 1947, are widely distributed in the Americas. The family Aspidoderidae includes the subfamilies Aspidoderinae Skrjabin and Schikobalova, 1947, and Lauroiinae Skrjabin and Schikobalova, 1951. These two subfamilies are delineated by the presence or absence of cephalic cordons at the anterior region. The nematodes in the subfamily Aspidoderinae, which includes the genus AspidoderaRailliet and Henry, 1912, are represented by nematodes with anterior cephalic cordons at the anterior end. The nematodes of the genus AspidoderaRailliet and Henry, 1912, are found in the cecum and large intestine of mammals of the orders Edentata, Marsupialia and Rodentia. Species within this genus have many morphological similarities. The use of scanning electron microscopy allows the specific characterization of the species within this genus. In the present work, we describe a new species of Aspidodera parasite of the large intestine of Didelphis aurita (Mammalia: Didelphidae) Wied-Neuwied, 1826, collected from Cachoeiras de Macacu, Rio de Janeiro. The combination of light and scanning electron microscopy allowed us a detailed analysis of this nematode.

  8. Physiologic reference ranges for captive black-tailed prairie dogs (Cynomys ludovicianus).

    PubMed

    Keckler, M Shannon; Gallardo-Romero, Nadia F; Langham, Gregory L; Damon, Inger K; Karem, Kevin L; Carroll, Darin S

    2010-05-01

    The black-tailed prairie dog (Cynomys ludovicianus) is a member of the order Rodentia and the family Sciuridae. Ecologically, prairie dogs are a keystone species in prairie ecology. This species is used as an animal model for human gallbladder disease and diseases caused by infection with Clostridium difficile, Yersinia pestis, Francisella tularensis, and most recently, Orthopoxvirus. Despite increasing numbers of prairie dogs used in research and kept as pets, few data are available on their baseline physiology in animal facility housing conditions. To establish baseline physiologic reference ranges, we designed a study using 18 wild-caught black-tailed prairie dogs. Telemetry data were analyzed to establish circadian rhythms for activity and temperature. In addition, hematologic and serum chemistry analyses were performed. Baseline measurements were used to establish the mean for each animal, which then were compiled and analyzed to determine the reference ranges. Here we present physiologic data on serum chemistry and hematology profiles, as well as weight, core body temperature, and daily activity patterns for black-tailed prairie dogs. These results reflect the use of multiple measurements from species- and age-matched prairie dogs and likely will be useful to ecologists, scientists interested in using this animal model in research, and veterinarians caring for pet prairie dogs.

  9. The power of social structure: how we became an intelligent lineage

    NASA Astrophysics Data System (ADS)

    de Sousa António, Marina Resendes; Schulze-Makuch, Dirk

    2011-01-01

    New findings pertinent to the human lineage origin (Ardipithecus ramidus) prompt a new analysis of the extrapolation of the social behavior of our closest relatives, the great apes, into human ‘natural social behavior’. With the new findings it becomes clear that human ancestors had very divergent social arrangements from the ones we observe today in our closest genetic relatives. The social structure of chimpanzees and gorillas is characterized by male competition. Aggression and the instigation of fear are common place. The morphology of A. ramidus points in the direction of a social system characterized by female-choice instead of male-male competition. This system tends to be characterized by reduced aggression levels, leading to more stable arrangements. It is postulated here that the social stability with accompanying group cohesion propitiated by this setting is favorable to the investment in more complex behaviors, the development of innovative approaches to solve familiar problems, an increase in exploratory behavior, and eventually higher intelligence and the use of sophisticated tools and technology. The concentration of research efforts into the study of social animals with similar social systems (e.g., New World social monkeys (Callitrichidae), social canids (Canidae) and social rodents (Rodentia)) are likely to provide new insights into the understanding of what factors determined our evolution into an intelligent species capable of advanced technology.

  10. A new genus and species of demodecid mites from the tongue of a house mouse Mus musculus: description of adult and immature stages with data on parasitism.

    PubMed

    Izdebska, J N; Rolbiecki, L

    2016-06-01

    The study of the parasitofauna of the house mouse Mus musculus (Rodentia: Muridae) Linnaeus is particularly important owing to its multiple relationships with humans - as a cosmopolitan, synanthropic rodent, bred for pets, food for other animals or laboratory animal. This article proposes and describes a new genus and species of the parasitic mite based on adult and immature stages from the house mouse. Glossicodex musculi gen. n., sp. n. is a medium-sized demodecid mite (adult stages on average 199 µm in length) found in mouse tissue of the tongue. It is characterized by two large, hooked claws on each tarsus of the legs; the legs are relatively massive, consisting of large, non-overlapping segments. The palps consist of three slender, clearly separated, relatively narrow segments, wherein their coxal segments are also quite narrow and spaced. Also, segments of the palps of larva and nymphs are clearly isolated, and on the terminal segment, trident claws that resemble legs' claws can be found. On the ventral side, in immature stages, triangular scuta, topped with sclerotized spur, can be also observed. Glossicodex musculi was noted in 10.8% of mice with a mean infection intensity of 2.2 parasites per host.

  11. Implications of Hybridization, NUMTs, and Overlooked Diversity for DNA Barcoding of Eurasian Ground Squirrels

    PubMed Central

    Ermakov, Oleg A.; Simonov, Evgeniy; Surin, Vadim L.; Titov, Sergey V.; Brandler, Oleg V.; Ivanova, Natalia V.; Borisenko, Alex V.

    2015-01-01

    The utility of DNA Barcoding for species identification and discovery has catalyzed a concerted effort to build the global reference library; however, many animal groups of economical or conservational importance remain poorly represented. This study aims to contribute DNA barcode records for all ground squirrel species (Xerinae, Sciuridae, Rodentia) inhabiting Eurasia and to test efficiency of this approach for species discrimination. Cytochrome c oxidase subunit 1 (COI) gene sequences were obtained for 97 individuals representing 16 ground squirrel species of which 12 were correctly identified. Taxonomic allocation of some specimens within four species was complicated by geographically restricted mtDNA introgression. Exclusion of individuals with introgressed mtDNA allowed reaching a 91.6% identification success rate. Significant COI divergence (3.5–4.4%) was observed within the most widespread ground squirrel species (Spermophilus erythrogenys, S. pygmaeus, S. suslicus, Urocitellus undulatus), suggesting the presence of cryptic species. A single putative NUMT (nuclear mitochondrial pseudogene) sequence was recovered during molecular analysis; mitochondrial COI from this sample was amplified following re-extraction of DNA. Our data show high discrimination ability of 100 bp COI fragments for Eurasian ground squirrels (84.3%) with no incorrect assessments, underscoring the potential utility of the existing reference librariy for the development of diagnostic ‘mini-barcodes’. PMID:25617768

  12. Environment-related and host-related factors affecting the occurrence of lice on rodents in Central Europe.

    PubMed

    Stanko, Michal; Fričová, Jana; Miklisová, Dana; Khokhlova, Irina S; Krasnov, Boris R

    2015-06-01

    We studied the effects of environment- (habitat, season) and host-related (sex, body mass) factors on the occurrence of four species of lice (Insecta:Phthiraptera:Anoplura) on six rodent species (Rodentia:Muridae). We asked how these factors influence the occurrence of lice on an individual host and whether different rodent-louse associations demonstrate consistent trends in these effects. We found significant effects of at least one environment-related and at least one host-related factor on the louse occurrence in five of six host-louse associations. The effect of habitat was significant in two associations with the occurrence of lice being more frequent in lowland than in mountain habitats. The effect of season was significant in five associations with a higher occurrence of infestation during the warm season in four associations and the cold season in one association. Host sex affected significantly the infestation by lice in three associations with a higher frequency of infestation in males. Host body mass affected the occurrence of lice in all five associations, being negative in wood mice and positive in voles. In conclusion, lice were influenced not only by the host- but also by environment-related factors. The effects of the latter could be mediated via life history parameters of a host.

  13. The effect of diet on microfaunal population and function in the caecum of a subterranean naked mole-rat, Heterocephalus glaber.

    PubMed

    Buffenstein, R; Yahav, S

    1991-03-01

    The effect of dietary fibre and starch content on digestibility, microfaunal population and caecal function was investigated in a subterranean mole-rat, Heterocephalus glaber (Rodentia). Mole-rats were fed on a diet of either sweet potato (neutral-detergent fibre (NDF) 65 g/kg dry matter (DM), starch 638 g/kg DM) or carrot (NDF 157 g/kg DM, starch 258.7 g/kg DM) for 4 weeks. Daily intake and faecal output were monitored. Thereafter caecal microfaunal population, density and function were assessed using light and scanning electron microscopy and by measuring both gas and short chain fatty acid (SCFA) production. A 2.4-fold increase in fibre and 2.5-fold decrease in starch content resulted in a decrease in caecal DM content (390 g/kg). A concomitant dramatic decline (by 93%) in ciliate protozoa with a corresponding 2-fold increase in bacteria also accompanied this change in diet. Fermentative efficiency as indicated by gas production was 2.6 times greater on a carrot diet than on sweet potato. Microbial fermentation resulted in higher SCFA concentrations on the carrot diet, with a 42% reduction in SCFA concentration on the sweet potato diet. Here, SCFA contributed 5.1% of daily energy expenditure and this increased 5.0-fold on the carrot diet. Caecal micro-organism function, therefore, played an important role in the nutritional physiology of these naked mole-rats, and enabled maximum utilization of the food substrate.

  14. The evolution of mammalian body temperature: the Cenozoic supraendothermic pulses.

    PubMed

    Lovegrove, Barry G

    2012-05-01

    In this study, I investigated the source(s) of variation in the body temperatures of mammals. I also attempted to reconstruct ancestral normothermic rest-phase body temperature states using a maximum parsimony approach. Body temperature at the familial level is not correlated with body mass. For small mammals, except the Macroscelidae, previously identified correlates, such as climate adaptation and zoogeography explained some, but not all, T(b) apomorphies. At the species level in large cursorial mammals, there was a significant correlation between body temperature and the ratio between metatarsal length and femur length, the proxy for stride length and cursoriality. With the exception of two primate families, all supraendothermic (T(b) > 37.9°C) mammals are cursorial, including Artiodactyla, Lagomorpha, some large Rodentia, and Carnivora. The ruminant supraendothermic cursorial pulse is putatively associated with global cooling and vegetation changes following the Paleocene-Eocene Thermal Maximum. Reconstructed ancestral body temperatures were highly unrealistic deep within the mammalian phylogeny because of the lack of fossil T(b) data that effectively creates ghost lineages. However, it is anticipated that the method of estimating body temperature from the abundance of ¹³C-¹⁸O bonds in the carbonate component of tooth bioapatite in both extant and extinct animals may be a very promising tool for estimating the T(b) of extinct mammals. Fossil T(b) data are essential for discerning derived T(b) reversals from ancestral states, and verifying the dates of supraendothermic pulses.

  15. Mammalian masticatory muscles: homology, nomenclature, and diversification.

    PubMed

    Druzinsky, Robert E; Doherty, Alison H; De Vree, Frits L

    2011-08-01

    There is a deep and rich literature of comparative studies of jaw muscles in mammals but no recent analyses employ modern phylogenetic techniques to better understand evolutionary changes that have occurred in these muscles. In order to fully develop and utilize the Feeding Experiments End-user Database (FEED), we are constructing a comprehensive ontology of mammalian jaw muscles. This process has led to a careful consideration of nomenclature and homologies of the muscles and their constituent parts. Precise determinations of muscle attachments have shown that muscles with similar names are not necessarily homologous. Using new anatomical descriptions derived from the literature, we defined character states for the jaw muscles in diverse mammalian species. We then mapped those characters onto a recent phylogeny of mammals with the aid of the Mesquite software package. Our data further elucidate how muscle groups associated with the feeding apparatus differ and have become highly specialized in certain mammalian orders, such as Rodentia, while remaining conserved in other orders. We believe that careful naming of muscles and statistical analyses of their distributions among mammals, in association with the FEED database, will lead to new, significant insights into the functional, structural, and evolutionary morphology of the jaw muscles.

  16. Bartonella infection in small mammals and their ectoparasites in Lithuania.

    PubMed

    Lipatova, Indre; Paulauskas, Algimantas; Puraite, Irma; Radzijevskaja, Jana; Balciauskas, Linas; Gedminas, Vaclovas

    2015-01-01

    The Bartonella pathogen is an emerging zoonotic agent. Epidemiological studies worldwide have demonstrated that small mammals are reservoir hosts of Bartonella spp. and their ectoparasites are potential vectors. The aim of this study was to investigate the prevalence of Bartonella infections in small mammals (Rodentia, Insectivora) and their ectoparasites (fleas and ticks) in Lithuania. A total of 430 small mammals representing nine species were captured with live-traps in Lithuania during 2013-2014. A total of 151 fleas representing eight species were collected from 109 (25.8%) small mammals. Five hundred and seventy ticks (Ixodes ricinus) were collected from 68 (16.1%) small mammals. Bartonella DNA was detected in 102 (23.7%) small mammals, 44 (29.1%) fleas and five (3.7%) pooled tick samples. Sequence analysis of 16S-23S rRNA ITS region showed that sequences were identical or similar to Bartonella grahamii, Bartonella taylorii and Bartonella rochalimae. This study is the first investigating the distribution and diversity of Bartonella species in small mammals and their ectoparasites in Lithuania. B. grahamii, B. taylorii, and B. rochalimae were detected in small mammals and their fleas, and B. grahamii in ticks obtained from small mammals.

  17. Kangaroo rats exhibit spongiform degeneration of the central auditory system similar to that found in gerbils.

    PubMed

    McGinn, M D; Faddis, B T

    1997-02-01

    Kangaroo rats develop spongiform degeneration of the central auditory system similar to that seen in the gerbil. Light microscopic and transmission electron microscopic study of the cochlear nucleus and auditory nerve root (ANR) of Dipodomys deserti and D. merriami show that spongiform lesions develop in dendrites and oligodendrocytes of the cochlear nucleus and in oligodendrocytes of the ANR that are morphologically indistinguishable from those extensively described in the Mongolian gerbil, Meriones unguiculatus. As in Mongolian gerbils, the spongiform degeneration in Dipodomys were much more numerous in animals continually exposed to modest levels of low-frequency noise (< 75 dB SPL). The kangaroo rats with extensive spongiform degeneration also show slightly, but significantly, elevated auditory brainstem evoked response (ABR) thresholds to low-frequency stimuli, a result also found in Mongolian gerbils. These results suggest that the elevated ABR thresholds may be the result of spongiform degeneration. Because low-frequency noise-induced spongiform degeneration has now been shown in the cochlear nucleus of animals from separate families of Rodentia (Heteromyidae and Muridae), the possibility should be investigated that similar noise-induced degenerative changes occur in the central auditory system of other mammals with good low-frequency hearing.

  18. Refugia in glacial ages led to the current discontinuous distribution patterns of the dark red-backed vole Myodes rex on Hokkaido, Japan.

    PubMed

    Kawai, Kuniko; Hailer, Frank; de Guia, Anna Pauline; Ichikawa, Hideo; Saitoh, Takashi

    2013-08-01

    The terrestrial mammalian fauna of the North Japanese island, Hokkaido, is more similar to that of Southern Siberia than to the main island of Japan, Honshu. Three species of the genus Myodes (Muridae, Rodentia) are found on Hokkaido, but not on Honshu. While Myodes rufocanus and M. rutilus are widely distributed across Hokkaido as well as the Eurasian continent, M. rex, which is endemic to Hokkaido and its adjacent islands, shows a discontinuous distribution pattern. We analyzed the phylogeographic history of M. rex using the mitochondrial DNA control region in order to interpret their discontinuous distribution pattern. Phylogenetic relationships among 54 distinct haplotypes showed that M. rex can be divided into four clades that occur on the northern, central, and southern regions of the Hokkaido mainland and on Rishiri Island, respectively. The phylogroups in the northern and central regions were largely separated in space, although several areas of sympatry were found. The phylogroup in the southern region, which was clearly separated from other phylogroups, showed markedly low genetic variability. All analyzed individuals from the population on Rishiri belonged to a separate lineage. Across a range of divergence rate estimates, we dated the basal divergence of all phylogroups to the mid to late Pleistocene, with subsequent signals of population expansion within lineages. We conclude that current phylogeographic structure in M. rex likely reflects Pleistocene survival in several separate refugia in situ. Past glacial ages have thus played an important role in shaping the current distribution patterns of mammalian species on Hokkaido.

  19. The wildlife research & rescue programme for mammals at Hulu Terengganu Hydroelectric Project (HTHEP), Terengganu, Peninsular Malaysia

    NASA Astrophysics Data System (ADS)

    Nur-Syuhada, N.; Magintan, D.; Siti-Hajar, A. R.; Aisah, M. S.; Shukor, M. N.

    2016-11-01

    During the inundation of the Hulu Terengganu Hydroelectric Project in October 2014, a wildlife rescue programme was conducted to rescue animals found trapped within the expanding 61.6 km2 reservoir. A total of 244 mammals from 30 species, representing 12 families were rescued by various methods included baited live trapping, catchpoles, hoop nets and by hand. The order Rodentia recorded the highest amount of rescued individuals at 20.9%, followed by Primate (18.9), Dermoptera (11.1), Carnivora (0.8) and Pholidota (0.4). The genus Rattus recorded the highest individuals rescued (51 individuals) probably due to the rapid clear-cut logging of the forest prior to inundation. Notable mammals of high conservational value rescued included Manis javanicus (Pangolin), Presbytis melalophos siamensis (Mitred Leaf Monkey), Trachypithecus obscurus (Dusky Leaf Monkey), Hylobates lar (White Handed Gibbon), Nycticebus coucang (Slow Loris), Galeopterus variegatus (Sunda Colugo), Callosciurus nigrovittatus (Sunda Black-banded Squirrel), Ratufa spp. (Giant Squirrels), and Sundasciurus hippurus (Horse-tailed Squirrel). Various data and biological samples were collected from the mammals rescued prior to their release at the nearest forest reserves. Rescue operation enabled the inventory and comprehensive data collection of various arboreal and rare mammal species that are hard to capture using the traditional survey method.

  20. Evolution of hantaviruses: co-speciation with reservoir hosts for more than 100 MYR.

    PubMed

    Plyusnin, Alexander; Sironen, Tarja

    2014-07-17

    The most recent (9th) Report of the International Committee on Taxonomy of Viruses (ICTV) lists 23 established and 30 provisional species in the genus Hantavirus (family Bunyaviridae) (Plyusnin et al., 2012). These virus species are harbored by altogether 51 species of rodents, shrews and moles and thus in most cases it is a relationship of "one hantavirus-one host". Such a tight bond between the two, in combination with the observed association between whole groups of hantaviruses and (sub)families of rodents, helped to develop the widely accepted view of a long-term co-evolution (co-speciation) of these viruses with their hosts. Accumulating evidence of host-switching events, both recent and ancient, however challenged some of the earlier views on hantavirus evolution. In this paper we discuss the concept of hantavirus-host co-speciation and propose a scenario of hantavirus evolution based on the currently available genetic information. This scenario is based on the hypothesis that hantaviruses are very ancient viruses which already existed at the estimated diversification point of major placental clades, of which one includes the ancestors of the order Rodentia and another the ancestors of both orders Eulipotyphla and Chiroptera; the diversification occurred approximately at 90-100 MYA. We also speculate that the evolutionary history of hantaviruses extents even deeper in the past, beyond this time-point, and included the transmission of a (pre)bunyavirus from an insect host to a mammal host.

  1. Implications of hybridization, NUMTs, and overlooked diversity for DNA Barcoding of Eurasian ground squirrels.

    PubMed

    Ermakov, Oleg A; Simonov, Evgeniy; Surin, Vadim L; Titov, Sergey V; Brandler, Oleg V; Ivanova, Natalia V; Borisenko, Alex V

    2015-01-01

    The utility of DNA Barcoding for species identification and discovery has catalyzed a concerted effort to build the global reference library; however, many animal groups of economical or conservational importance remain poorly represented. This study aims to contribute DNA barcode records for all ground squirrel species (Xerinae, Sciuridae, Rodentia) inhabiting Eurasia and to test efficiency of this approach for species discrimination. Cytochrome c oxidase subunit 1 (COI) gene sequences were obtained for 97 individuals representing 16 ground squirrel species of which 12 were correctly identified. Taxonomic allocation of some specimens within four species was complicated by geographically restricted mtDNA introgression. Exclusion of individuals with introgressed mtDNA allowed reaching a 91.6% identification success rate. Significant COI divergence (3.5-4.4%) was observed within the most widespread ground squirrel species (Spermophilus erythrogenys, S. pygmaeus, S. suslicus, Urocitellus undulatus), suggesting the presence of cryptic species. A single putative NUMT (nuclear mitochondrial pseudogene) sequence was recovered during molecular analysis; mitochondrial COI from this sample was amplified following re-extraction of DNA. Our data show high discrimination ability of 100 bp COI fragments for Eurasian ground squirrels (84.3%) with no incorrect assessments, underscoring the potential utility of the existing reference librariy for the development of diagnostic 'mini-barcodes'.

  2. Molecular and paleontological evidence for a post-Cretaceous origin of rodents.

    PubMed

    Wu, Shaoyuan; Wu, Wenyu; Zhang, Fuchun; Ye, Jie; Ni, Xijun; Sun, Jimin; Edwards, Scott V; Meng, Jin; Organ, Chris L

    2012-01-01

    The timing of the origin and diversification of rodents remains controversial, due to conflicting results from molecular clocks and paleontological data. The fossil record tends to support an early Cenozoic origin of crown-group rodents. In contrast, most molecular studies place the origin and initial diversification of crown-Rodentia deep in the Cretaceous, although some molecular analyses have recovered estimated divergence times that are more compatible with the fossil record. Here we attempt to resolve this conflict by carrying out a molecular clock investigation based on a nine-gene sequence dataset and a novel set of seven fossil constraints, including two new rodent records (the earliest known representatives of Cardiocraniinae and Dipodinae). Our results indicate that rodents originated around 61.7-62.4 Ma, shortly after the Cretaceous/Paleogene (K/Pg) boundary, and diversified at the intraordinal level around 57.7-58.9 Ma. These estimates are broadly consistent with the paleontological record, but challenge previous molecular studies that place the origin and early diversification of rodents in the Cretaceous. This study demonstrates that, with reliable fossil constraints, the incompatibility between paleontological and molecular estimates of rodent divergence times can be eliminated using currently available tools and genetic markers. Similar conflicts between molecular and paleontological evidence bedevil attempts to establish the origination times of other placental groups. The example of the present study suggests that more reliable fossil calibration points may represent the key to resolving these controversies.

  3. Jumping and gliding rodents: mitogenomic affinities of Pedetidae and Anomaluridae deduced from an RNA-Seq approach.

    PubMed

    Fabre, Pierre-Henri; Jønsson, Knud A; Douzery, Emmanuel J P

    2013-12-01

    An RNA-Seq strategy was used to obtain the complete set of protein-coding mitochondrial genes from two rodent taxa. Thanks to the next generation sequencing (NGS) 454 approach, we determined the complete mitochondrial DNA genome from Graphiurus kelleni (Mammalia: Rodentia: Gliridae) and partial mitogenome from Pedetes capensis (Pedetidae), and compared them with published rodent and outgroup mitogenomes. We finished the mitogenome sequencing by a series of amplicons using conserved PCR primers to fill the gaps corresponding to tRNA, rRNA and control regions. Phylogenetic analyses of the mitogenomes suggest a well-supported rodent phylogeny in agreement with nuclear gene trees. Pedetes groups with Anomalurus into the clade Anomaluromorpha, while Graphiurus branches within the squirrel-related clade. Moreover, Pedetes+Anomalurus branch with Castor into the mouse-related clade. Our study demonstrates the utility of NGS for obtaining new mitochondrial genomes as well as the importance of choosing adequate models of sequence evolution to infer the phylogeny of rodents.

  4. Coordinated scaling of cortical and cerebellar numbers of neurons.

    PubMed

    Herculano-Houzel, Suzana

    2010-01-01

    While larger brains possess concertedly larger cerebral cortices and cerebella, the relative size of the cerebral cortex increases with brain size, but relative cerebellar size does not. In the absence of data on numbers of neurons in these structures, this discrepancy has been used to dispute the hypothesis that the cerebral cortex and cerebellum function and have evolved in concert and to support a trend towards neocorticalization in evolution. However, the rationale for interpreting changes in absolute and relative size of the cerebral cortex and cerebellum relies on the assumption that they reflect absolute and relative numbers of neurons in these structures across all species - an assumption that our recent studies have shown to be flawed. Here I show for the first time that the numbers of neurons in the cerebral cortex and cerebellum are directly correlated across 19 mammalian species of four different orders, including humans, and increase concertedly in a similar fashion both within and across the orders Eulipotyphla (Insectivora), Rodentia, Scandentia and Primata, such that on average a ratio of 3.6 neurons in the cerebellum to every neuron in the cerebral cortex is maintained across species. This coordinated scaling of cortical and cerebellar numbers of neurons provides direct evidence in favor of concerted function, scaling and evolution of these brain structures, and suggests that the common notion that equates cognitive advancement with neocortical expansion should be revisited to consider in its stead the coordinated scaling of neocortex and cerebellum as a functional ensemble.

  5. Coordinated Scaling of Cortical and Cerebellar Numbers of Neurons

    PubMed Central

    Herculano-Houzel, Suzana

    2010-01-01

    While larger brains possess concertedly larger cerebral cortices and cerebella, the relative size of the cerebral cortex increases with brain size, but relative cerebellar size does not. In the absence of data on numbers of neurons in these structures, this discrepancy has been used to dispute the hypothesis that the cerebral cortex and cerebellum function and have evolved in concert and to support a trend towards neocorticalization in evolution. However, the rationale for interpreting changes in absolute and relative size of the cerebral cortex and cerebellum relies on the assumption that they reflect absolute and relative numbers of neurons in these structures across all species – an assumption that our recent studies have shown to be flawed. Here I show for the first time that the numbers of neurons in the cerebral cortex and cerebellum are directly correlated across 19 mammalian species of four different orders, including humans, and increase concertedly in a similar fashion both within and across the orders Eulipotyphla (Insectivora), Rodentia, Scandentia and Primata, such that on average a ratio of 3.6 neurons in the cerebellum to every neuron in the cerebral cortex is maintained across species. This coordinated scaling of cortical and cerebellar numbers of neurons provides direct evidence in favor of concerted function, scaling and evolution of these brain structures, and suggests that the common notion that equates cognitive advancement with neocortical expansion should be revisited to consider in its stead the coordinated scaling of neocortex and cerebellum as a functional ensemble. PMID:20300467

  6. Biostratigraphy and biochronology of the Monte Hermoso Formation (early Pliocene) at its type locality, Buenos Aires Province, Argentina

    NASA Astrophysics Data System (ADS)

    Tomassini, Rodrigo L.; Montalvo, Claudia I.; Deschamps, Cecilia M.; Manera, Teresa

    2013-12-01

    The Monte Hermoso Formation, cropping out at its type locality of Farola Monte Hermoso (Buenos Aires Province), is a classical fossiliferous unit of the South American Neogene, highlighted by the abundance and diversity of its vertebrate remains. However, its biostratigraphy and age have been largely debated, and numerous discrepancies and controversies have been stated. In this regard, the result of the analysis of new materials recovered from the different levels of this formation, following a strict control of stratigraphic provenance, is here reported. As well, the provenance of specimens of previous collections has been evaluated. The studied assemblage consists of Osteichthyes, Amphibia, Reptilia, Aves and Mammalia. These latter are the most numerous and belong to the Didelphimorphia, Polydolopimorphia, Rodentia, Notoungulata, Litopterna and Xenarthra. The recorded taxa suggest no important faunistic variations among the different levels of the Monte Hermoso Formation that would imply significant chronological differences, and hence, justify the recognition of two biostratigraphic units. The analysis of the first and last records as well as the taxa considered as exclusive, does not support the validity of the biozones of Trigodon gaudryi and Neocavia depressidens previously proposed. On this basis, a new scheme for the Monte Hermoso Formation at its type locality is proposed, including a new single biostratigraphic unit. This unit is the Eumysops laeviplicatus Range Zone, which represents the biostratigraphic base for the Montehermosan Stage/Age of the early Pliocene.

  7. Detection of Rickettsia spp. and host and habitat associations of fleas (Siphonaptera) in eastern Taiwan.

    PubMed

    Kuo, C C; Huang, J L; Lin, T E; Wang, H C

    2012-09-01

    Rickettsia typhi and Rickettsia felis (Rickettsiales: Rickettsiaceae) are two rickettsiae principally transmitted by fleas, but the detection of either pathogen has rarely been attempted in Taiwan. Of 2048 small mammals trapped in eastern Taiwan, Apodemus agrarius Pallas (24.5%) and Mus caroli Bonhote (24.4%) (both: Rodentia: Muridae) were the most abundant, and M. caroli hosted the highest proportion of fleas (63.9% of 330 fleas). Two flea species were identified: Stivalius aporus Jordan and Rothschild (Siphonaptera: Stivaliidae), and Acropsylla episema Rothschild (Siphonaptera: Leptopsyllidae). Nested polymerase chain reaction targeting parts of the ompB and gltA genes showed six fleas to be positive for Rickettsia spp. (3.8% of 160 samples), which showed the greatest similarity to R. felis, Rickettsia japonica, Rickettsia conorii or Rickettsia sp. TwKM01. Rickettsia typhi was not detected in the fleas and Rickettsia co-infection did not occur. Both flea species were more abundant during months with lower temperatures and less rainfall, and flea abundance on M. caroli was not related to soil hardness, vegetative height, ground cover by litter or by understory layer, or the abundance of M. caroli. Our study reveals the potential circulation of R. felis and other rickettsiae in eastern Taiwan, necessitating further surveillance of rickettsial diseases in this region. This is especially important because many novel rickettsioses are emerging worldwide.

  8. Impact of Anthropogenic Disturbance on Native and Invasive Trypanosomes of Rodents in Forested Uganda.

    PubMed

    Salzer, Johanna S; Pinto, C Miguel; Grippi, Dylan C; Williams-Newkirk, Amanda Jo; Peterhans, Julian Kerbis; Rwego, Innocent B; Carroll, Darin S; Gillespie, Thomas R

    2016-12-01

    Habitat disturbance and anthropogenic change are globally associated with extinctions and invasive species introductions. Less understood is the impact of environmental change on the parasites harbored by endangered, extinct, and introduced species. To improve our understanding of the impacts of anthropogenic disturbance on such host-parasite interactions, we investigated an invasive trypanosome (Trypanosoma lewisi). We screened 348 individual small mammals, representing 26 species, from both forested and non-forested habitats in rural Uganda. Using microscopy and PCR, we identified 18% of individuals (order Rodentia) as positive for trypanosomes. Further phylogenetic analyses revealed two trypanosomes circulating-T. lewisi and T. varani. T. lewisi was found in seven species both native and invasive, while T. varani was identified in only three native forest species. The lack of T. varani in non-forested habitats suggests that it is a natural parasite of forest-dwelling rodents. Our findings suggest that anthropogenic disturbance may lead to spillover of an invasive parasite (T. lewisi) from non-native to native species, and lead to local co-extinction of a native parasite (T. varani) and native forest-dwelling hosts.

  9. Collagen Fingerprinting: A New Screening Technique for Radiocarbon Dating Ancient Bone

    PubMed Central

    Harvey, Virginia L.; Egerton, Victoria M.; Chamberlain, Andrew T.; Manning, Phillip L.; Buckley, Michael

    2016-01-01

    Collagen is the dominant organic component of bone and is intimately locked within the hydroxyapatite structure of this ubiquitous biomaterial that dominates archaeological and palaeontological assemblages. Radiocarbon analysis of extracted collagen is one of the most common approaches to dating bone from late Pleistocene or Holocene deposits, but dating is relatively expensive compared to other biochemical techniques. Numerous analytical methods have previously been investigated for the purpose of screening out samples that are unlikely to yield reliable dates including histological analysis, UV-stimulated fluorescence and, most commonly, the measurement of percentage nitrogen (%N) and ratio of carbon to nitrogen (C:N). Here we propose the use of collagen fingerprinting (also known as Zooarchaeology by Mass Spectrometry, or ZooMS, when applied to species identification) as an alternative screening method for radiocarbon dating, due to its ability to provide information on collagen presence and quality, alongside species identification. The method was tested on a series of sub-fossil bone specimens from cave systems on Cayman Brac (Cayman Islands), chosen due to the observable range in diagenetic alteration, and in particular, the extent of mineralisation. Six 14C dates, of 18 initial attempts, were obtained from remains of extinct hutia, Capromys sp. (Rodentia; Capromyidae), recovered from five distinct caves on Cayman Brac, and ranging from 393 ± 25 to 1588 ± 26 radiocarbon years before present (yr BP). All of the bone samples that yielded radiocarbon dates generated excellent collagen fingerprints, and conversely those that gave poor fingerprints also failed dating. Additionally, two successfully fingerprinted bone samples were screened out from a set of 81. Both subsequently generated 14C dates, demonstrating successful utilisation of ZooMS as an alternative screening mechanism to identify bone samples that are suitable for 14C analysis. PMID:26938469

  10. Threat Diversity Will Erode Mammalian Phylogenetic Diversity in the Near Future

    PubMed Central

    Jono, Clémentine M. A.; Pavoine, Sandrine

    2012-01-01

    To reduce the accelerating rate of phylogenetic diversity loss, many studies have searched for mechanisms that could explain why certain species are at risk, whereas others are not. In particular, it has been demonstrated that species might be affected by both extrinsic threat factors as well as intrinsic biological traits that could render a species more sensitive to extinction; here, we focus on extrinsic factors. Recently, the International Union for Conservation of Nature developed a new classification of threat types, including climate change, urbanization, pollution, agriculture and aquaculture, and harvesting/hunting. We have used this new classification to analyze two main factors that could explain the expected future loss of mammalian phylogenetic diversity: 1. differences in the type of threats that affect mammals and 2. differences in the number of major threats that accumulate for a single species. Our results showed that Cetartiodactyla, Diprotodontia, Monotremata, Perissodactyla, Primates, and Proboscidea could lose a high proportion of their current phylogenetic diversity in the coming decades. In contrast, Chiroptera, Didelphimorphia, and Rodentia could lose less phylogenetic diversity than expected if extinctions were random. Some mammalian clades, including Marsupiala, Chiroptera, and a subclade of Primates, are affected by particular threat types, most likely due solely to their geographic locations and associations with particular habitats. However, regardless of the geography, habitat, and taxon considered, it is not the threat type, but the threat diversity that determines the extinction risk for species and clades. Thus, some mammals might be randomly located in areas subjected to a large diversity of threats; they might also accumulate detrimental traits that render them sensitive to different threats, which is a characteristic that could be associated with large body size. Any action reducing threat diversity is expected to have a

  11. Deterioration of the Gαo Vomeronasal Pathway in Sexually Dimorphic Mammals

    PubMed Central

    Suárez, Rodrigo; Fernández-Aburto, Pedro; Manger, Paul R.; Mpodozis, Jorge

    2011-01-01

    In mammals, social and sexual behaviours are largely mediated by the vomeronasal system (VNS). The accessory olfactory bulb (AOB) is the first synaptic locus of the VNS and ranges from very large in Caviomorph rodents, small in carnivores and ungulates, to its complete absence in apes, elephants, most bats and aquatic species. Two pathways have been described in the VNS of mammals. In mice, vomeronasal neurons expressing Gαi2 protein project to the rostral portion of the AOB and respond mostly to small volatile molecules, whereas neurons expressing Gαo project to the caudal AOB and respond mostly to large non-volatile molecules. However, the Gαo-expressing pathway is absent in several species (horses, dogs, musk shrews, goats and marmosets) but no hypotheses have been proposed to date to explain the loss of that pathway. We noted that the species that lost the Gαo pathway belong to Laurasiatheria and Primates lineages, both clades with ubiquitous sexual dimorphisms across species. To assess whether similar events of Gαo pathway loss could have occurred convergently in dimorphic species we studied G-protein expression in the AOB of two species that independently evolved sexually dimorphic traits: the California ground squirrel Spermophilus beecheyi (Rodentia; Sciurognathi) and the cape hyrax Procavia capensis (Afrotheria; Hyracoidea). We found that both species show uniform expression of Gαi2-protein throughout AOB glomeruli, while Gαo expression is restricted to main olfactory glomeruli only. Our results suggest that the degeneration of the Gαo-expressing vomeronasal pathway has occurred independently at least four times in Eutheria, possibly related to the emergence of sexual dimorphisms and the ability of detecting the gender of conspecifics at distance. PMID:22039487

  12. Expensive Brains: “Brainy” Rodents have Higher Metabolic Rate

    PubMed Central

    Sobrero, Raúl; May-Collado, Laura J.; Agnarsson, Ingi; Hernández, Cristián E.

    2011-01-01

    Brains are the centers of the nervous system of animals, controlling the organ systems of the body and coordinating responses to changes in the ecological and social environment. The evolution of traits that correlate with cognitive ability, such as relative brain size is thus of broad interest. Brain mass relative to body mass (BM) varies among mammals, and diverse factors have been proposed to explain this variation. A recent study provided evidence that energetics play an important role in brain evolution (Isler and van Schaik, 2006). Using composite phylogenies and data drawn from multiple sources, these authors showed that basal metabolic rate (BMR) correlates with brain mass across mammals. However, no such relationship was found within rodents. Here we re-examined the relationship between BMR and brain mass within Rodentia using a novel species-level phylogeny. Our results are sensitive to parameter evaluation; in particular how species mass is estimated. We detect no pattern when applying an approach used by previous studies, where each species BM is represented by two different numbers, one being the individual that happened to be used for BMR estimates of that species. However, this approach may compromise the analysis. When using a single value of BM for each species, whether representing a single individual, or available species mean, our findings provide evidence that brain mass (independent of BM) and BMR are correlated. These findings are thus consistent with the hypothesis that large brains evolve when the payoff for increased brain mass is greater than the energetic cost they incur. PMID:21811456

  13. TRANEXAMIC ACID ACTION ON LIVER REGENERATION AFTER PARTIAL HEPATECTOMY: EXPERIMENTAL MODEL IN RATS

    PubMed Central

    SOBRAL, Felipe Antonio; DAGA, Henrique; RASERA, Henrique Nogueira; PINHEIRO, Matheus da Rocha; CELLA, Igor Furlan; MORAIS, Igor Henrique; MARQUES, Luciana de Oliveira; COLLAÇO, Luiz Martins

    2016-01-01

    ABSTRACT Background: Different lesions may affect the liver resulting in harmful stimuli. Some therapeutic procedures to treat those injuries depend on liver regeneration to increase functional capacity of this organ. Aim: Evaluate the effects of tranexamic acid on liver regeneration after partial hepatectomy in rats. Method: 40 rats (Rattus norvegicus albinus, Rodentia mammalia) of Wistar-UP lineage were randomly divided into two groups named control (CT) and tranexamic acid (ATX), with 20 rats in each. Both groups were subdivided, according to liver regeneration time of 32 h or seven days after the rats had been operated. The organ regeneration was evaluated through weight and histology, stained with HE and PCNA. Results: The average animal weight of ATX and CT 7 days groups before surgery were 411.2 g and 432.7 g, and 371.3 g and 392.9 g after the regeneration time, respectively. The average number of mitotic cells stained with HE for the ATX and CT 7 days groups were 33.7 and 32.6 mitosis, and 14.5 and 14.9 for the ATX and CT 32 h groups, respectively. When stained with proliferating cell nuclear antigen, the numbers of mitotic cells counted were 849.7 for the ATX 7 days, 301.8 for the CT 7 days groups, 814.2 for the ATX 32 hand 848.1 for the CT 32 h groups. Conclusion: Tranexamic acid was effective in liver regeneration, but in longer period after partial hepatectomy. PMID:27438036

  14. Rodent Species Distribution and Hantavirus Seroprevalence in Residential and Forested areas of Sarawak, Malaysia.

    PubMed

    Hamdan, Nur Elfieyra Syazana; Ng, Yee Ling; Lee, Wei Bin; Tan, Cheng Siang; Khan, Faisal Ali Anwarali; Chong, Yee Ling

    2017-01-01

    Rodents belong to the order Rodentia, which consists of three families in Borneo (i.e., Muridae, Sciuridae and Hystricidae). These include rats, mice, squirrels, and porcupines. They are widespread throughout the world and considered pests that harm humans and livestock. Some rodent species are natural reservoirs of hantaviruses (Family: Bunyaviridae) that can cause zoonotic diseases in humans. Although hantavirus seropositive human sera were reported in Peninsular Malaysia in the early 1980s, information on their infection in rodent species in Malaysia is still lacking. The rodent populations in residential and forested areas in Sarawak were sampled. A total of 108 individuals from 15 species of rodents were collected in residential (n = 44) and forested ( n = 64) areas. The species diversity of rodents in forested areas was significantly higher (H = 2.2342) compared to rodents in residential areas (H = 0.64715) (p < 0.001 of Zar-t test based on the Shannon index). Rattus rattus and Sundamys muelleri were present at high frequencies in both localities. An enzyme-linked immunosorbent assay (ELISA) showed that hantavirus-targeting antibodies were absent from 53 tested serum samples. This is the first report of hantavirus seroprevalence surveillance in rodent populations in Sarawak, East Malaysia. The results suggested that hantavirus was not circulating in the studied rodent populations in Sarawak, or it was otherwise at a low prevalence that is below the detection threshold. It is important to remain vigilant because of the zoonotic potential of this virus and its severe disease outcome. Further studies, such as molecular detection of viral genetic materials, are needed to fully assess the risk of hantavirus infection in rodents and humans in this region of Malaysia.

  15. Dung beetles (Coleoptera: Scarabaeidae) attracted to dung of the largest herbivorous rodent on earth: a comparison with human feces.

    PubMed

    Puker, Anderson; Correa, César M A; Korasaki, Vanesca; Ferreira, Kleyton R; Oliveira, Naiara G

    2013-12-01

    The capybara, Hydrochoerus hydrochaeris (L.) (Rodentia: Caviidae), is the largest herbivorous rodent on Earth and abundant in the Neotropical region, which can provide a stable food source of dung for dung beetle communities (Coleoptera: Scarabaeidae: Scarabaeinae). However, the use of capybara dung by dung beetles is poorly known. Here, we present data on the structure of the dung beetle community attracted to capybara dung and compare with the community attracted to human feces. Dung beetles were captured with pitfall traps baited with fresh capybara dung and human feces in pastures with exotic grass (Brachiaria spp.), patches of Brazilian savanna (Cerrado), and points of degraded riparian vegetation along the Aquidauana river in Anastácio and Aquidauana, Mato Grosso do Sul, Brazil. In traps baited with human feces, 13,809 individuals of 31 species were captured, and in those baited with capybara dung 1,027 individuals belonging to 26 species were captured. The average number of individuals and species captured by the traps baited with human feces was greater than for capybara dung in all habitats studied. Composition of the communities attracted to human feces and capybara dung formed distinct groups in all habitats. Despite the smaller number of species and individuals captured in capybara dung when compared with human feces, capybara dung was attractive to dung beetles. In Brazil, the legalization of hunting these rodents has been debated, which would potentially affect the community and consequently the ecological functions performed by dung beetles that use the feces of these animals as a resource. In addition, the knowledge of the communities associated with capybaras may be important in predicting the consequences of future management of their populations.

  16. A survey of hemoparasite infections in free-ranging mammals and reptiles in French Guiana.

    PubMed

    de Thoisy, B; Michel, J C; Vogel, I; Vié, J C

    2000-10-01

    Blood smears of 1,353 free-ranging mammals (35 species) and 112 reptiles (31 species) from French Guiana were examined for hemoparasites. Parasites from 3 major groups were recorded: Apicomplexa (including hemogregarines, piroplasms, and Plasmodium spp.), Trypanosomatidae, and Filaroidea. Fifty percent of the individuals (86% of the species) were infected by parasites from at least 1 group. Hemogregarines, identified as Hepatozoon sp., infected numerous snakes with high prevalences (30-100%); infection is reported for the first time in 5 host genera of snakes: Clelia, Oxybelis, Pseustes, Rhinobotryum, and Bothriopsis. Infections were also observed in 4 marsupial species and 1 rodent. Hepatozoon spp. recorded in Didelphis albiventris (Marsupialia) and Coendou prehensilis (Rodentia) may be new species. Plasmodium sp. were observed in 2 snake species, Dipsas indica (Colubridae) and Bothrops atrox (Viperidae). Plasmodium brasilianum was recorded in all 5 primate species examined. Piroplasms were observed in all mammal orders except primates. Large terrestrial rodents were the main hosts of members of the Babesidae; 42% of Myoprocta acouchy, 36% of Dasyprocta agouti, and 44% of Agouti paca were infected. Trypanosomes were common in mammals and were recorded in 70% of the examined genera. Trypanosoma cruzi-like infections were reported in 21 mammal species, including sloths, rodents, carnivores, and primates. Microfilariae were also widespread, with higher prevalences in sloths, anteaters, and porcupines (>40% of the individuals infected) and in tamarins (95% infected). This survey highlights some potential anthropozoonotic risks due to the recent further evidence of Plasmodium brasilianum and P. malariae as a single species and to the increased diversity of hosts for Trypanosoma cruzi.

  17. Ecological Niche Modeling of main reservoir hosts of zoonotic cutaneous leishmaniasis in Iran.

    PubMed

    Gholamrezaei, Mostafa; Mohebali, Mehdi; Hanafi-Bojd, Ahmad Ali; Sedaghat, Mohammad Mehdi; Shirzadi, Mohammad Reza

    2016-08-01

    Zoonotic cutaneous leishmaniasis (ZCL), caused by Leishmania major, is a common zoonotic vector-borne disease in Iran. Close contact with infected reservoir hosts increases the probability of transmission of Leishmania parasite infections to susceptible humans. Four gerbil species (Rodentia: Gerbillidae) serve as the main reservoir hosts for ZCL in different endemic foci of Iran. These species include Rhombomys opimus, Meriones libycus, Meriones hurrianae and Tatera indica; while notable infection has been reported in Nesokia indica as well. The purpose of this study is to model the distribution of these reservoirs to identify the risk areas of ZCL. A data bank was developed including all published data during the period of 1970-2015. Maximum entropy model was used to find the most appropriate ecological niches for each species. The areas under curve obtained were 0.961, 0.927, 0.922, 0.997 and 0.899, instead of 1, for training test in R. opimus, M. libycus, T. indica, M. hurrianae and N. indica, respectively. The environmental variable with the highest gain when used in isolation was slope for R. opimus and N. indica, annual mean temperature for M. libycus, and seasonal precipitation for T. indica and M. hurrianae. Summation of presence probabilities for three main species, i.e., R. opimus, M. libycus and T. indica revealed favorable ecological niches in wide areas of 16 provinces. This is the first study to predict the distribution of ZCL reservoir hosts in Iran. Climatology and topography variables had high contributions toward the prediction of potential distribution of the main reservoir species; therefore, as climate changes, the models should be updated periodically with novel data, and the results should be used in disease-monitoring programs.

  18. Detection and characterization of Shiga toxin-producing Escherichia coli in captive non-domestic mammals.

    PubMed

    Leotta, Gerardo A; Deza, Natalia; Origlia, Javier; Toma, Claudia; Chinen, Isabel; Miliwebsky, Elizabeth; Iyoda, Sunao; Sosa-Estani, Sergio; Rivas, Marta

    2006-11-26

    Shiga toxin producing-Escherichia coli (STEC) is an important emerging pathogen, and ruminants are recognized as their main natural reservoir. The aim of this work was to establish the frequency of STEC in non-domestic mammals of the Zoo and Botanical Garden of La Plata City, Argentina, and to pheno-genotypically characterize STEC isolates. By polymerase chain reaction (PCR), Shiga toxin (stx) gene sequences were detected in 50.8% of 65 fecal samples. Twenty-five STEC strains were isolated from 38.5% of the Zoo's animals. Ten species of order Cetartiodactyla and one species of order Rodentia were recognized as new STEC carriers. STEC strains belonged to 7 different serotypes including new serotypes O12:H25 and O13:H6. Serotype O146:H28, previously associated with human infections, represented 24% of STEC isolates. The most frequent Shiga toxin identified were type 1c and type 2c. Nineteen strains were positive for iha gene, 8 strains were positive for ehxA gene. Moreover, all strains were positive for lpfAO113 and negative for rfbO157, eae, saa, lpfAO157/OI-141, lpfAO157/OI-154, efa1, and toxB genes. Results obtained by XbaI-pulsed-field gel electrophoresis (XbaI-PFGE) confirmed the transmission of STEC strains among different animal species and suborders. In addition, we observed a potential association between STEC-harboring animal and factors such as belonging to order Cetartiodactyla, living in a pit, and belonging to a non-autochthonous species. This is the first work developed with zoological mammals and STEC in Argentina.

  19. Heterothermy in Afrotropical mammals and birds: a review.

    PubMed

    McKechnie, Andrew E; Mzilikazi, Nomakwezi

    2011-09-01

    Recent years have seen a rapid increase in the number of Afrotropical endotherms known to avoid mismatches between energy supply and demand by using daily torpor and/or hibernation. Among mammals, heterothermy has been reported in 40 species in six orders, namely Macroscelidea, Afrosoricida, Rodentia, Eulipotyphla, Primates and Chiroptera. These species span a range in body mass of 7-770 g, with minimum heterothermic body temperatures ranging from 1-27°C and bout length varying from 1 h to 70 days. Daily torpor is the most common form of heterothermy, with true hibernation being observed in only seven species, Graphiurus murinus, Graphiurus ocularis, Atelerix frontalis, Cheirogaleus medius, Cheirogaleus major, Microcebus murinus and Microcebus griseorufus. The traditional distinction between daily torpor and hibernation is blurred in some species, with free-ranging individuals exhibiting bouts of > 24 h and body temperatures < 16 °C, but none of the classical behaviours associated with hibernation. Several species bask in the sun during rewarming. Among birds, heterothermy has been reported in 16 species in seven orders, and is more pronounced in phylogenetically older taxa. Both in mammals and birds, patterns of heterothermy can vary dramatically among species occurring at a particular site, and even among individuals of a single species. For instance, patterns of heterothermy among cheirogalid primates in western Madagascar vary from daily torpor to uninterrupted hibernation for up to seven months. Other examples of variation among closely-related species involve small owls, elephant shrews and vespertilionid bats. There may also be variation in terms of the ecological correlates of torpor within a species, as is the case in the Freckled Nightjar Caprimulgus tristigma.

  20. New Insights into the Phylogeny and Gene Context Analysis of Binder of Sperm Proteins (BSPs)

    PubMed Central

    Arruga, Diana; Pérez-Pé, Rosaura; Sánchez-Ferrer, Álvaro; Muiño-Blanco, Teresa; Cebrián-Pérez, José A.

    2015-01-01

    Seminal plasma (SP) proteins support the survival of spermatozoa acting not only at the plasma membrane but also by inhibition of capacitation, resulting in higher fertilizing ability. Among SP proteins, BSP (binder of sperm) proteins are the most studied, since they may be useful for the improvement of semen diluents, storage and subsequent fertilization results. However, an updated and detailed phylogenetic analysis of the BSP protein superfamily has not been carried out with all the sequences described in the main databases. The update view shows for the first time an equally distributed number of sequences between the three families: BSP, and their homologs 1 (BSPH1) and 2 (BSPH2). The BSP family is divided in four subfamilies, BSP1 subfamily being the predominant, followed by subfamilies BSP3, BSP5 and BSP2. BSPH proteins were found among placental mammals (Eutheria) belonging to the orders Proboscidea, Primates, Lagomorpha, Rodentia, Chiroptera, Perissodactyla and Cetartiodactyla. However, BSPH2 proteins were also found in the Scandentia order and Metatheria clade. This phylogenetic analysis, when combined with a gene context analysis, showed a completely new evolutionary scenario for the BSP superfamily of proteins with three defined different gene patterns, one for BSPs, one for BSPH1/BSPH2/ELSPBP1 and another one for BSPH1/BSPH2 without ELSPBP1. In addition, the study has permitted to define concise conserved blocks for each family (BSP, BSPH1 and BSPH2), which could be used for a more reliable assignment for the incoming sequences, for data curation of current databases, and for cloning new BSPs, as the one described in this paper, ram seminal vesicle 20 kDa protein (RSVP20, Ovis aries BSP5b). PMID:26333091

  1. Threat diversity will erode mammalian phylogenetic diversity in the near future.

    PubMed

    Jono, Clémentine M A; Pavoine, Sandrine

    2012-01-01

    To reduce the accelerating rate of phylogenetic diversity loss, many studies have searched for mechanisms that could explain why certain species are at risk, whereas others are not. In particular, it has been demonstrated that species might be affected by both extrinsic threat factors as well as intrinsic biological traits that could render a species more sensitive to extinction; here, we focus on extrinsic factors. Recently, the International Union for Conservation of Nature developed a new classification of threat types, including climate change, urbanization, pollution, agriculture and aquaculture, and harvesting/hunting. We have used this new classification to analyze two main factors that could explain the expected future loss of mammalian phylogenetic diversity: 1. differences in the type of threats that affect mammals and 2. differences in the number of major threats that accumulate for a single species. Our results showed that Cetartiodactyla, Diprotodontia, Monotremata, Perissodactyla, Primates, and Proboscidea could lose a high proportion of their current phylogenetic diversity in the coming decades. In contrast, Chiroptera, Didelphimorphia, and Rodentia could lose less phylogenetic diversity than expected if extinctions were random. Some mammalian clades, including Marsupiala, Chiroptera, and a subclade of Primates, are affected by particular threat types, most likely due solely to their geographic locations and associations with particular habitats. However, regardless of the geography, habitat, and taxon considered, it is not the threat type, but the threat diversity that determines the extinction risk for species and clades. Thus, some mammals might be randomly located in areas subjected to a large diversity of threats; they might also accumulate detrimental traits that render them sensitive to different threats, which is a characteristic that could be associated with large body size. Any action reducing threat diversity is expected to have a

  2. Comparative sacral morphology and the reconstructed tail lengths of five extinct primates: Proconsul heseloni, Epipliopithecus vindobonensis, Archaeolemur edwardsi, Megaladapis grandidieri, and Palaeopropithecus kelyus.

    PubMed

    Russo, Gabrielle A

    2016-01-01

    This study evaluated the relationship between the morphology of the sacrum-the sole bony link between the tail or coccyx and the rest of the body-and tail length (including presence/absence) and function using a comparative sample of extant mammals spanning six orders (Primates, Carnivora, Rodentia, Diprotodontia, Pilosa, Scandentia; N = 472). Phylogenetically-informed regression methods were used to assess how tail length varied with respect to 11 external and internal (i.e., trabecular) bony sacral variables with known or suspected biomechanical significance across all mammals, only primates, and only non-primates. Sacral variables were also evaluated for primates assigned to tail categories ('tailless,' 'nonprehensile short-tailed,' 'nonprehensile long-tailed,' and 'prehensile-tailed'). Compared to primates with reduced tail lengths, primates with longer tails generally exhibited sacra having larger caudal neural openings than cranial neural openings, and last sacral vertebrae with more mediolaterally-expanded caudal articular surfaces than cranial articular surfaces, more laterally-expanded transverse processes, more dorsally-projecting spinous processes, and larger caudal articular surface areas. Observations were corroborated by the comparative sample, which showed that shorter-tailed (e.g., Lynx rufus [bobcat]) and longer-tailed (e.g., Acinonyx jubatus [cheetah]) non-primate mammals morphologically converge with shorter-tailed (e.g., Macaca nemestrina) and longer-tailed (e.g., Macaca fascicularis) primates, respectively. 'Prehensile-tailed' primates exhibited last sacral vertebrae with more laterally-expanded transverse processes and greater caudal articular surface areas than 'nonprehensile long-tailed' primates. Internal sacral variables performed poorly compared to external sacral variables in analyses of extant primates, and were thus deemed less useful for making inferences concerning tail length and function in extinct primates. The tails lengths of

  3. Evolution of C, D and S-type cystatins in mammals: an extensive gene duplication in primates.

    PubMed

    de Sousa-Pereira, Patrícia; Abrantes, Joana; Pinheiro, Ana; Colaço, Bruno; Vitorino, Rui; Esteves, Pedro J

    2014-01-01

    Cystatins are a family of inhibitors of cysteine peptidases that comprises the salivary cystatins (D and S-type cystatins) and cystatin C. These cystatins are encoded by a multigene family (CST3, CST5, CST4, CST1 and CST2) organized in tandem in the human genome. Their presence and functional importance in human saliva has been reported, however the distribution of these proteins in other mammals is still unclear. Here, we performed a proteomic analysis of the saliva of several mammals and studied the evolution of this multigene family. The proteomic analysis detected S-type cystatins (S, SA, and SN) in human saliva and cystatin D in rat saliva. The evolutionary analysis showed that the cystatin C encoding gene is present in species of the most representative mammalian groups, i.e. Artiodactyla, Rodentia, Lagomorpha, Carnivora and Primates. On the other hand, D and S-type cystatins are mainly retrieved from Primates, and especially the evolution of S-type cystatins seems to be a dynamic process as seen in Pongo abelii genome where several copies of CST1-like gene (cystatin SN) were found. In Rodents, a group of cystatins previously identified as D and S has also evolved. Despite the high divergence of the amino acid sequence, their position in the phylogenetic tree and their genome organization suggests a common origin with those of the Primates. These results suggest that the D and S type cystatins have emerged before the mammalian radiation and were retained only in Primates and Rodents. Although the mechanisms driving the evolution of cystatins are unknown, it seems to be a dynamic process with several gene duplications evolving according to the birth-and-death model of evolution. The factors that led to the appearance of a group of saliva-specific cystatins in Primates and its rapid evolution remain undetermined, but may be associated with an adaptive advantage.

  4. Spatial and Temporal Activity Patterns of the Free-Living Giant Mole-Rat (Fukomys mechowii), the Largest Social Bathyergid

    PubMed Central

    Lövy, Matěj; Šklíba, Jan; Šumbera, Radim

    2013-01-01

    Despite the considerable attention devoted to the biology of social species of African mole-rats (Bathyergidae, Rodentia), knowledge is lacking about their behaviour under natural conditions. We studied activity of the largest social bathyergid, the giant mole-rat Fukomys mechowii, in its natural habitat in Zambia using radio-telemetry. We radio-tracked six individuals during three continuous 72-h sessions. Five of these individuals, including a breeding male, belonged to a single family group; the remaining female was probably a solitary disperser. The non-breeders of the family were active (i.e. outside the nest) 5.8 hours per 24h-day with the activity split into 6.5 short bouts. The activity was more concentrated in the night hours, when the animals also travelled longer distances from the nest. The breeding male spent only 3.2 hours per day outside the nest, utilizing less than 20% of the whole family home range. The dispersing female displayed a much different activity pattern than the family members. Her 8.0 hours of outside-nest activity per day were split into 4.6 bouts which were twice as long as in the family non-breeders. Her activity peak in the late afternoon coincided with the temperature maximum in the depth of 10 cm (roughly the depth of the foraging tunnels). Our results suggest that the breeding individuals (at least males) contribute very little to the work of the family group. Nevertheless, the amount of an individual's activity and its daily pattern are probably flexible in this species and can be modified in response to actual environmental and social conditions. PMID:23383166

  5. Collagen Fingerprinting: A New Screening Technique for Radiocarbon Dating Ancient Bone.

    PubMed

    Harvey, Virginia L; Egerton, Victoria M; Chamberlain, Andrew T; Manning, Phillip L; Buckley, Michael

    2016-01-01

    Collagen is the dominant organic component of bone and is intimately locked within the hydroxyapatite structure of this ubiquitous biomaterial that dominates archaeological and palaeontological assemblages. Radiocarbon analysis of extracted collagen is one of the most common approaches to dating bone from late Pleistocene or Holocene deposits, but dating is relatively expensive compared to other biochemical techniques. Numerous analytical methods have previously been investigated for the purpose of screening out samples that are unlikely to yield reliable dates including histological analysis, UV-stimulated fluorescence and, most commonly, the measurement of percentage nitrogen (%N) and ratio of carbon to nitrogen (C:N). Here we propose the use of collagen fingerprinting (also known as Zooarchaeology by Mass Spectrometry, or ZooMS, when applied to species identification) as an alternative screening method for radiocarbon dating, due to its ability to provide information on collagen presence and quality, alongside species identification. The method was tested on a series of sub-fossil bone specimens from cave systems on Cayman Brac (Cayman Islands), chosen due to the observable range in diagenetic alteration, and in particular, the extent of mineralisation. Six (14)C dates, of 18 initial attempts, were obtained from remains of extinct hutia, Capromys sp. (Rodentia; Capromyidae), recovered from five distinct caves on Cayman Brac, and ranging from 393 ± 25 to 1588 ± 26 radiocarbon years before present (yr BP). All of the bone samples that yielded radiocarbon dates generated excellent collagen fingerprints, and conversely those that gave poor fingerprints also failed dating. Additionally, two successfully fingerprinted bone samples were screened out from a set of 81. Both subsequently generated (14)C dates, demonstrating successful utilisation of ZooMS as an alternative screening mechanism to identify bone samples that are suitable for 1(4)C analysis.

  6. Avian influenza in birds and mammals.

    PubMed

    Cardona, Carol J; Xing, Zheng; Sandrock, Christian E; Davis, Cristina E

    2009-07-01

    The disease syndromes caused by avian influenza viruses are highly variable depending on the host species infected, its susceptibility and response to infection and the virulence of the infecting viral strain. Although avian influenza viruses have a broad host range in general, it is rare for an individual strain or subtype to infect more than one species. The H5N1 highly pathogenic avian influenza virus (HPAIV) lineages of viruses that descended from A/goose/Guandong/96 (H5N1 HPAIV) are unusual in the diversity of species they have infected worldwide. Although the species affected by H5N1 HPAI in the field and those that have been experimentally studied are diverse, their associated disease syndromes are remarkably similar across species. In some species, multi-organ failure and death are rapid and no signs of the disease are observed. Most prominently in this category are chickens and other avian species of the order Galliformes. In other species, neurologic signs develop resulting in the death of the host. This is what has been reported in domestic cats (Carnivora), geese (Anseriformes), ratites (Struthioniformes), pigeons inoculated with high doses (Columbiformes) and ducks infected with H5N1 HPAIV isolated since 2002 (Anseriformes). In some other species, the disease is more prolonged and although multi-organ failure and death are the eventual outcomes, the signs of disease are more extensive. Predominantly, these species include humans (Primates) and the laboratory models of human disease, the ferret (Carnivora), mouse (Rodentia) and cynamologous macaques (Primates). Finally, some species are more resistant to infection with H5N1 HPAIV and show few or no signs of disease. These species include pigeons in some studies (Columbiformes), ducks inoculated with pre-2002 isolates (Anseriformes), and pigs (Artiodactyla).

  7. Discovery of mammalian hosts to Gnathostoma nipponicum larvae and prevalence of the larvae in rodents and insectivores.

    PubMed

    Oyamada, T; Kobayashi, H; Kindou, T; Kudo, N; Yoshikawa, H; Yoshikawa, T

    1996-09-01

    From September 1993 to November 1995, to clarify the natural infection of Gnathostoma nipponicum (G.n.) larvae in small wild mammals, a total of 313 animals consisted of three species of rodents and two species of insectivores, collected from an endemic area of this nematode in Aomori Prefecture, were investigated. Two species, Rattus norvegicus (R.n.) and Chimarrogale himalayica (C.h.) were infected with G.n. larvae, and the infection rate was extremely high with 27.2% and 72.7% in the former and latter. The infected animals harbored the larvae of 2-10 (mean: 6.0) in R.N. and 2-40 (10.6) in C.h., and a total of 273 larvae was recovered. The all larvae (18) from R.n. and the vast majority of the larvae (216/255: 82.4%) from C.h. were recovered from the musculature, and many encapsulated larvae were found in these portions of C.h. Taxonomically, all the larvae were identified as the advance third-stage larvae (AdL3) of G.n. The body length was 1,056-2,110 microns, and was larger than those of the naturally-infected AdL3 reported from cold-blooded animals. No morphological alterations or death of the larva was observed. From these results, it would seem that R.n. and C.h. are highly susceptible to G.n. larvae, and has very suitable characteristics as the hosts. Furthermore, a hypothesis is advanced that these mammals serves as the plausible paratenic hosts in the life cycle of G.n. This report is the first record of R.n. (Rodentia) and C.h. (Insectivora) naturally-infected with AdL3 of G.n.

  8. Cholinergic urethral brush cells are widespread throughout placental mammals.

    PubMed

    Deckmann, Klaus; Krasteva-Christ, Gabriela; Rafiq, Amir; Herden, Christine; Wichmann, Judy; Knauf, Sascha; Nassenstein, Christina; Grevelding, Christoph G; Dorresteijn, Adriaan; Chubanov, Vladimir; Gudermann, Thomas; Bschleipfer, Thomas; Kummer, Wolfgang

    2015-11-01

    We previously identified a population of cholinergic epithelial cells in murine, human and rat urethrae that exhibits a structural marker of brush cells (villin) and expresses components of the canonical taste transduction signaling cascade (α-gustducin, phospholipase Cβ2 (PLCβ2), transient receptor potential cation channel melanostatin 5 (TRPM5)). These cells serve as sentinels, monitoring the chemical composition of the luminal content for potentially hazardous compounds such as bacteria, and initiate protective reflexes counteracting further ingression. In order to elucidate cross-species conservation of the urethral chemosensory pathway we investigated the occurrence and molecular make-up of urethral brush cells in placental mammals. We screened 11 additional species, at least one in each of the five mammalian taxonomic units primates, carnivora, perissodactyla, artiodactyla and rodentia, for immunohistochemical labeling of the acetylcholine synthesizing enzyme, choline acetyltransferase (ChAT), villin, and taste cascade components (α-gustducin, PLCβ2, TRPM5). Corresponding to findings in previously investigated species, urethral epithelial cells with brush cell shape were immunolabeled in all 11 mammals. In 8 species, immunoreactivities against all marker proteins and ChAT were observed, and double-labeling immunofluorescence confirmed the cholinergic nature of villin-positive and chemosensory (TRPM5-positive) cells. In cat and horse, these cells were not labeled by the ChAT antiserum used in this study, and unspecific reactions of the secondary antiserum precluded conclusions about ChAT-expression in the bovine epithelium. These data indicate that urethral brush cells are widespread throughout the mammalian kingdom and evolved not later than about 64.5millionyears ago.

  9. Rodent Species Distribution and Hantavirus Seroprevalence in Residential and Forested areas of Sarawak, Malaysia

    PubMed Central

    Hamdan, Nur Elfieyra Syazana; Ng, Yee Ling; Lee, Wei Bin; Tan, Cheng Siang; Khan, Faisal Ali Anwarali; Chong, Yee Ling

    2017-01-01

    Rodents belong to the order Rodentia, which consists of three families in Borneo (i.e., Muridae, Sciuridae and Hystricidae). These include rats, mice, squirrels, and porcupines. They are widespread throughout the world and considered pests that harm humans and livestock. Some rodent species are natural reservoirs of hantaviruses (Family: Bunyaviridae) that can cause zoonotic diseases in humans. Although hantavirus seropositive human sera were reported in Peninsular Malaysia in the early 1980s, information on their infection in rodent species in Malaysia is still lacking. The rodent populations in residential and forested areas in Sarawak were sampled. A total of 108 individuals from 15 species of rodents were collected in residential (n = 44) and forested ( n = 64) areas. The species diversity of rodents in forested areas was significantly higher (H = 2.2342) compared to rodents in residential areas (H = 0.64715) (p < 0.001 of Zar-t test based on the Shannon index). Rattus rattus and Sundamys muelleri were present at high frequencies in both localities. An enzyme-linked immunosorbent assay (ELISA) showed that hantavirus-targeting antibodies were absent from 53 tested serum samples. This is the first report of hantavirus seroprevalence surveillance in rodent populations in Sarawak, East Malaysia. The results suggested that hantavirus was not circulating in the studied rodent populations in Sarawak, or it was otherwise at a low prevalence that is below the detection threshold. It is important to remain vigilant because of the zoonotic potential of this virus and its severe disease outcome. Further studies, such as molecular detection of viral genetic materials, are needed to fully assess the risk of hantavirus infection in rodents and humans in this region of Malaysia. PMID:28228923

  10. Faster Speciation and Reduced Extinction in the Tropics Contribute to the Mammalian Latitudinal Diversity Gradient

    PubMed Central

    Rolland, Jonathan; Condamine, Fabien L.; Jiguet, Frederic; Morlon, Hélène

    2014-01-01

    The increase in species richness from the poles to the tropics, referred to as the latitudinal diversity gradient, is one of the most ubiquitous biodiversity patterns in the natural world. Although understanding how rates of speciation and extinction vary with latitude is central to explaining this pattern, such analyses have been impeded by the difficulty of estimating diversification rates associated with specific geographic locations. Here, we use a powerful phylogenetic approach and a nearly complete phylogeny of mammals to estimate speciation, extinction, and dispersal rates associated with the tropical and temperate biomes. Overall, speciation rates are higher, and extinction rates lower, in the tropics than in temperate regions. The diversity of the eight most species-rich mammalian orders (covering 92% of all mammals) peaks in the tropics, except that of the Lagomorpha (hares, rabbits, and pikas) reaching a maxima in northern-temperate regions. Latitudinal patterns in diversification rates are strikingly consistent with these diversity patterns, with peaks in species richness associated with low extinction rates (Primates and Lagomorpha), high speciation rates (Diprotodontia, Artiodactyla, and Soricomorpha), or both (Chiroptera and Rodentia). Rates of range expansion were typically higher from the tropics to the temperate regions than in the other direction, supporting the “out of the tropics” hypothesis whereby species originate in the tropics and disperse into higher latitudes. Overall, these results suggest that differences in diversification rates have played a major role in shaping the modern latitudinal diversity gradient in mammals, and illustrate the usefulness of recently developed phylogenetic approaches for understanding this famous yet mysterious pattern. PMID:24492316

  11. Historical biogeography of the strepsirhine primates of Madagascar.

    PubMed

    Tattersall, Ian

    2006-01-01

    Lying some 400 km off the coast of southeastern Africa, Madagascar is the world's largest oceanic island. It has been in roughly the same position relative to its parent continent for 120 million years, and as a consequence its mammal fauna is unusual in composition, with a low number of major taxa but a high diversity at lower taxonomic levels. Among Madagascar's native terrestrial mammals, only the orders Primates, Rodentia, Carnivora and Insectivora are represented (plus, until recently, the enigmatic and endemic Bibymalagasia, and Artiodactyla in the form of semiaquatic pygmy hippopotamuses). This reflects the fact that terrestrial mammals are notoriously poor over-water dispersers; yet at the same time the ancestors of all of Madagascar's mammals had to have crossed a wide oceanic barrier to get to the island at various points during the Tertiary. Here I examine the palaeogeographic evidence for potential land bridge or 'stepping-stone' connections with adjacent continents from the Mesozoic through the Cenozoic, and review the fossil records and phylogenies of each of Madagascar's mammalian groups in an attempt to estimate the minimum number of crossings necessary to produce the island's current faunal composition. Probable monophyletic origins for each major group, and thus a smaller rather than a larger number of crossings of the Mozambique Channel, imply that this water barrier has acted as a powerful filter; so powerful that it is unclear whether any crossings would have been possible without some form of subaerial connection, however ephemeral, at least from time to time during the Tertiary. Clarification of how Madagascar's terrestrial mammal fauna may have originated is thus as likely to emerge from the geology of the seafloor surrounding the island as it is to come from the fossil record or from the internal and external relationships of its various components.

  12. Next-Generation Sequencing for Rodent Barcoding: Species Identification from Fresh, Degraded and Environmental Samples

    PubMed Central

    Galan, Maxime; Pagès, Marie; Cosson, Jean-François

    2012-01-01

    Rodentia is the most diverse order among mammals, with more than 2,000 species currently described. Most of the time, species assignation is so difficult based on morphological data solely that identifying rodents at the specific level corresponds to a real challenge. In this study, we compared the applicability of 100 bp mini-barcodes from cytochrome b and cytochrome c oxidase 1 genes to enable rodent species identification. Based on GenBank sequence datasets of 115 rodent species, a 136 bp fragment of cytochrome b was selected as the most discriminatory mini-barcode, and rodent universal primers surrounding this fragment were designed. The efficacy of this new molecular tool was assessed on 946 samples including rodent tissues, feces, museum samples and feces/pellets from predators known to ingest rodents. Utilizing next-generation sequencing technologies able to sequence mixes of DNA, 1,140 amplicons were tagged, multiplexed and sequenced together in one single 454 GS-FLX run. Our method was initially validated on a reference sample set including 265 clearly identified rodent tissues, corresponding to 103 different species. Following validation, 85.6% of 555 rodent samples from Europe, Asia and Africa whose species identity was unknown were able to be identified using the BLASTN program and GenBank reference sequences. In addition, our method proved effective even on degraded rodent DNA samples: 91.8% and 75.9% of samples from feces and museum specimens respectively were correctly identified. Finally, we succeeded in determining the diet of 66.7% of the investigated carnivores from their feces and 81.8% of owls from their pellets. Non-rodent species were also identified, suggesting that our method is sensitive enough to investigate complete predator diets. This study demonstrates how this molecular identification method combined with high-throughput sequencing can open new realms of possibilities in achieving fast, accurate and inexpensive species identification

  13. A First Generation Comparative Chromosome Map between Guinea Pig (Cavia porcellus) and Humans

    PubMed Central

    Romanenko, Svetlana A.; Perelman, Polina L.; Trifonov, Vladimir A.; Serdyukova, Natalia A.; Li, Tangliang; Fu, Beiyuan; O’Brien, Patricia C. M.; Ng, Bee L.; Nie, Wenhui; Liehr, Thomas; Stanyon, Roscoe; Graphodatsky, Alexander S.; Yang, Fengtang

    2015-01-01

    The domesticated guinea pig, Cavia porcellus (Hystricomorpha, Rodentia), is an important laboratory species and a model for a number of human diseases. Nevertheless, genomic tools for this species are lacking; even its karyotype is poorly characterized. The guinea pig belongs to Hystricomorpha, a widespread and important group of rodents; so far the chromosomes of guinea pigs have not been compared with that of other hystricomorph species or with any other mammals. We generated full sets of chromosome-specific painting probes for the guinea pig by flow sorting and microdissection, and for the first time, mapped the chromosomal homologies between guinea pig and human by reciprocal chromosome painting. Our data demonstrate that the guinea pig karyotype has undergone extensive rearrangements: 78 synteny-conserved human autosomal segments were delimited in the guinea pig genome. The high rate of genome evolution in the guinea pig may explain why the HSA7/16 and HSA16/19 associations presumed ancestral for eutherians and the three syntenic associations (HSA1/10, 3/19, and 9/11) considered ancestral for rodents were not found in C. porcellus. The comparative chromosome map presented here is a starting point for further development of physical and genetic maps of the guinea pig as well as an aid for genome assembly assignment to specific chromosomes. Furthermore, the comparative mapping will allow a transfer of gene map data from other species. The probes developed here provide a genomic toolkit, which will make the guinea pig a key species to unravel the evolutionary biology of the Hystricomorph rodents. PMID:26010445

  14. Nuclear organization and morphology of cholinergic, putative catecholaminergic and serotonergic neurons in the brain of the Cape porcupine (Hystrix africaeaustralis): increased brain size does not lead to increased organizational complexity.

    PubMed

    Limacher, Aude'marie; Bhagwandin, Adhil; Fuxe, Kjell; Manger, Paul R

    2008-09-01

    The distribution, morphology and nuclear organization of the cholinergic, putative catecholaminergic and serotonergic systems within the brain of the Cape porcupine (Hystrix africaeaustralis) were identified following immunohistochemistry for choline acetyltransferase, tyrosine hydroxylase and serotonin. The aim of the present study was to investigate possible differences in the complement of nuclear subdivisions of these systems in the Cape porcupine in comparison with previous studies of these systems in other rodents. The Cape porcupine is the largest rodent in which these systems have been examined and has an adult body mass of 10-24kg and an average brain mass of approximately 37g, around 15 times larger than the laboratory rat. The Cape porcupines were taken from the wild and while these differences, especially that of mass, may lead to the prediction of a significant difference in the nuclear organization or number within these systems, all the nuclei observed in all three systems in the laboratory rat and in other rodents had direct homologues in the brain of the Cape porcupine. Moreover, there were no additional nuclei in the brain of the Cape porcupine that are not found in the laboratory rat or other rodents studied and vice versa. It is noted that the medial septal nucleus of the Cape porcupine appeared qualitatively to have a reduced number of neurons in comparison to the laboratory rat and other rodents. The locus coeruleus of the laboratory rat differs in location to that observed for the Cape porcupine and several other rodent species. The Cape porcupine is distantly related to the laboratory rat, but still a member of the order Rodentia; thus, changes in the organization of these systems appears to demonstrate a form of constraint related to the phylogenetic level of the order.

  15. Next-generation sequencing for rodent barcoding: species identification from fresh, degraded and environmental samples.

    PubMed

    Galan, Maxime; Pagès, Marie; Cosson, Jean-François

    2012-01-01

    Rodentia is the most diverse order among mammals, with more than 2,000 species currently described. Most of the time, species assignation is so difficult based on morphological data solely that identifying rodents at the specific level corresponds to a real challenge. In this study, we compared the applicability of 100 bp mini-barcodes from cytochrome b and cytochrome c oxidase 1 genes to enable rodent species identification. Based on GenBank sequence datasets of 115 rodent species, a 136 bp fragment of cytochrome b was selected as the most discriminatory mini-barcode, and rodent universal primers surrounding this fragment were designed. The efficacy of this new molecular tool was assessed on 946 samples including rodent tissues, feces, museum samples and feces/pellets from predators known to ingest rodents. Utilizing next-generation sequencing technologies able to sequence mixes of DNA, 1,140 amplicons were tagged, multiplexed and sequenced together in one single 454 GS-FLX run. Our method was initially validated on a reference sample set including 265 clearly identified rodent tissues, corresponding to 103 different species. Following validation, 85.6% of 555 rodent samples from Europe, Asia and Africa whose species identity was unknown were able to be identified using the BLASTN program and GenBank reference sequences. In addition, our method proved effective even on degraded rodent DNA samples: 91.8% and 75.9% of samples from feces and museum specimens respectively were correctly identified. Finally, we succeeded in determining the diet of 66.7% of the investigated carnivores from their feces and 81.8% of owls from their pellets. Non-rodent species were also identified, suggesting that our method is sensitive enough to investigate complete predator diets. This study demonstrates how this molecular identification method combined with high-throughput sequencing can open new realms of possibilities in achieving fast, accurate and inexpensive species identification.

  16. Dengue infection in neotropical forest mammals.

    PubMed

    de Thoisy, Benoît; Lacoste, Vincent; Germain, Adeline; Muñoz-Jordán, Jorge; Colón, Candimar; Mauffrey, Jean-François; Delaval, Marguerite; Catzeflis, François; Kazanji, Mirdad; Matheus, Séverine; Dussart, Philippe; Morvan, Jacques; Setién, Alvaro Aguilar; Deparis, Xavier; Lavergne, Anne

    2009-04-01

    In South America, dengue is the arbovirus-transmitted disease with the highest incidence. Unlike other arboviruses, wild mammals have no confirmed role in the cycle of dengue in the neotropics, although serological studies have suggested a possible secondary amplification cycle involving mammals other than nonhuman primates. In French Guiana, where all four serotypes (DENV-1, DENV-2, DENV-3, DENV-4) are present, the disease is endemic with outbreak events. To determine whether wild mammals can be infected by DENV, rodents, marsupials, and bats were captured over several periods, from 2001 to 2007, at two sites. The first location is a secondary forest surrounded by an urban area where dengue is endemic. The second location is a forest edge site where the disease has not yet emerged. A total of 10,000 trap-nights were performed and 616 mammals were captured. RNAs representing the four DENV serotypes were detected at both sites by reverse-transcriptase polymerase chain reaction in the livers and/or sera of 92 mammals belonging to 14 out of 32 species distributed among all the orders investigated: Rodentia (33 positive/146 tested), Marsupialia (40/318), and Chiroptera (19/152). Sequence analyses of a portion of the capsid and premembrane junction revealed that mammal strains of DENV-1, DENV-2, DENV-3, and DENV-4 had only 92.6%, 89%, 95%, and 95.8% identity, respectively, with strains circulating in the human population during the same periods. Regarding DENV-2, strains related (99% identity) to those responsible for an epidemic event in humans in French Guiana concurrent to the capture sessions were also evidenced, suggesting that wild mammals in edge habitats can be infected by circulating human strains. Our results demonstrate, for the first time, that neotropical wild mammals can be infected with dengue virus. The question of whether mammals maintain DENV in enzootic cycles and can play a role in its reemergence in human populations remains to be answered.

  17. Complete mitochondrial genome of the Eurasian flying squirrel Pteromys volans (Sciuromorpha, Sciuridae) and revision of rodent phylogeny.

    PubMed

    Ryu, Shi Hyun; Kwak, Min Jung; Hwang, Ui Wook

    2013-02-01

    In this study, the complete mitochondrial genome of the Eurasian flying squirrel Pteromys volans (Rodentia, Sciuromorpha, Sciuridae) was sequenced and characterized in detail. The entire mitochondrial genome of P. volans consisted of 16,513 bp and contained 13 protein-coding genes, 22 tRNA genes, two rRNA genes, and two non-coding regions. Its gene arrangement pattern was consistent with the mammalian ground pattern. The overall base composition and AT contents were similar to those of other rodent mitochondrial genomes. The light-strand origin generally identified between tRNA ( Asn ) and tRNA ( Cys ) consisted of a secondary structure with an 11-bp stem and an 11-bp loop. The large control region was constructed of three characteristic domains, ETAS, CD, and CSB without any repeat sequences. Each domain contained ETAS1, subsequences A, B, and C, and CSB1, respectively. In order to examine phylogenetic contentious issues of the monophyly of rodents and phylogenetic relationships among five rodent suborders, here, phylogenetic analyses based on nucleotide sequence data of the 35 rodent and 3 lagomorph mitochondrial genomes were performed using the Bayesian inference and maximum likelihood method. The result strongly supported the rodent monophyly with high node confidence values (BP 100 % in ML and BPP 1.00 in BI) and also monophylies of four rodent suborders (BP 85-100 % in ML and BPP 1.00 in BI), except for Anomalumorpha in which only one species was examined here. Also, phylogenetic relationships among the five rodent suborders were suggested and discussed in detail.

  18. Faster speciation and reduced extinction in the tropics contribute to the Mammalian latitudinal diversity gradient.

    PubMed

    Rolland, Jonathan; Condamine, Fabien L; Jiguet, Frederic; Morlon, Hélène

    2014-01-01

    The increase in species richness from the poles to the tropics, referred to as the latitudinal diversity gradient, is one of the most ubiquitous biodiversity patterns in the natural world. Although understanding how rates of speciation and extinction vary with latitude is central to explaining this pattern, such analyses have been impeded by the difficulty of estimating diversification rates associated with specific geographic locations. Here, we use a powerful phylogenetic approach and a nearly complete phylogeny of mammals to estimate speciation, extinction, and dispersal rates associated with the tropical and temperate biomes. Overall, speciation rates are higher, and extinction rates lower, in the tropics than in temperate regions. The diversity of the eight most species-rich mammalian orders (covering 92% of all mammals) peaks in the tropics, except that of the Lagomorpha (hares, rabbits, and pikas) reaching a maxima in northern-temperate regions. Latitudinal patterns in diversification rates are strikingly consistent with these diversity patterns, with peaks in species richness associated with low extinction rates (Primates and Lagomorpha), high speciation rates (Diprotodontia, Artiodactyla, and Soricomorpha), or both (Chiroptera and Rodentia). Rates of range expansion were typically higher from the tropics to the temperate regions than in the other direction, supporting the "out of the tropics" hypothesis whereby species originate in the tropics and disperse into higher latitudes. Overall, these results suggest that differences in diversification rates have played a major role in shaping the modern latitudinal diversity gradient in mammals, and illustrate the usefulness of recently developed phylogenetic approaches for understanding this famous yet mysterious pattern.

  19. Occurrence of ectoparasitic arthropods associated with rodents in Hail region northern Saudi Arabia.

    PubMed

    Asiry, Khalid A; Fetoh, Badr El-Sabah A

    2014-09-01

    Ectoparasitic arthropods are a diverse element of the Saudi fauna. Due to this, a survey of ectoparasites associated with rodents was conducted as a preliminary study in five districts of Hail region of northern Saudi Arabia for the first time. Ectoparasites extracted from 750 rodents were sampled and identified by recording their frequency of appearance. Results revealed that 1,287 ectoparasites infested 316 of the captured rodent hosts. These ectoparasites parasitized on four species of rodents including three species of rats Rattus rattus rattus, Rattus rattus frugivorus, and Rattus rattus alexandrinus and one species of mouse Acomys dimidiatus (Rodentia: Muridae). The ectoparasites belong to four different groups: ticks, fleas, lice, and mites. Ticks were the highest in the number, while fleas were the lowest among all the extracted ectoparasite groups. The collected ectoparasitic arthropods consisted of seven species. Ticks were of two species: Rhipicephalus turanicus and Rhipicephalus sanguineus (Acari: Ixodidae), fleas were of two species: Xenopsylla cheopis and Xenopsyllus conformis mycerini (Siphonaptera: Pulicidae), lice was a single species: Polyplax serrata (Anoplura: Hoplopleuridae), and mites were of two species: Laelaps nuttali and Laelaps echidninus (Mesostigmata: Laelapidae). The findings of the study showed that the intensity of infestation was varied between rodent host sexes, wherein females had the highest rate of parasitic infestation, and the parasitic index of appearance was very high for one group of parasites (i.e., ticks). The parasitic prevalence was