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1

Chorioallantoic placentation in Galea spixii (Rodentia, Caviomorpha, Caviidae)  

PubMed Central

Background Placentas of guinea pig-related rodents are appropriate animal models for human placentation because of their striking similarities to those of humans. To optimize the pool of potential models in this context, it is essential to identify the occurrence of characters in close relatives. Methods In this study we first analyzed chorioallantoic placentation in the prea, Galea spixii, as one of the guinea pig's closest relatives. Material was collected from a breeding group at the University of Mossoró, Brazil, including 18 individuals covering an ontogenetic sequence from initial pregnancy to term. Placentas were investigated by means of histology, electron microscopy, immunohistochemistry (vimentin, ?-smooth muscle actin, cytokeration) and proliferation activity (PCNA). Results Placentation in Galea is primarily characterized by an apparent regionalization into labyrinth, trophospongium and subplacenta. It also has associated growing processes with clusters of proliferating trophoblast cells at the placental margin, internally directed projections and a second centre of proliferation in the labyrinth. Finally, the subplacenta, which is temporarily supplied in parallel by the maternal and fetal blood systems, served as the center of origin for trophoblast invasion. Conclusion Placentation in Galea reveals major parallels to the guinea pig and other caviomorphs with respect to the regionalization of the placenta, the associated growing processes, as well as trophoblast invasion. A principal difference compared to the guinea pig occurred in the blood supply of the subplacenta. Characteristics of the invasion and expanding processes indicate that Galea may serve as an additional animal model that is much smaller than the guinea pig and where the subplacenta partly has access to both maternal and fetal blood systems. PMID:18771596

Oliveira, Moacir F; Mess, Andrea; Ambrósio, Carlos E; Dantas, Carlos AG; Favaron, Phelipe O; Miglino, Maria A

2008-01-01

2

Chromosomal evolution in Rodentia  

PubMed Central

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. PMID:22086076

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

2012-01-01

3

Hematologic and plasma biochemical values of Spix's macaws (Cyanopsitta spixii).  

PubMed

The Spix's macaw (Cyanopsitta spixii) is considered the world's most endangered parrot, with the last wild bird disappearing in 2001 and only 74 birds in captivity. To establish hematologic and plasma biochemical reference ranges and to look for differences relative to sex, age, and season, we obtained blood samples from 46 captive Spix's macaws (23 male, 23 female) housed in aviaries at the Al Wabra Wildlife Preservation in the State of Qatar. No significant differences in hematologic or plasma biochemical values were found between females and males. Adult and juvenile birds differed in mean concentrations of glucose, total protein, amylase, cholesterol, and phosphorus; in percentages of heterophils and lymphocytes; and in the absolute lymphocyte count. Total protein, cholesterol, and phosphorus concentrations; hematocrit; and heterophil and lymphocyte counts differed significantly by season. Baseline hematologic and plasma biochemical ranges were established, which may be useful as reference values for clinicians working with this highly endangered species. PMID:18351006

Foldenauer, Ulrike; Borjal, Raffy Jim; Deb, Amrita; Arif, Abdi; Taha, Abid Sharif; Watson, Ryan William; Steinmetz, Hanspeter; Bürkle, Marcellus; Hammer, Sven

2007-12-01

4

Radiographic measurement of internal organs in Spix's macaws (Cyanopsitta spixii).  

PubMed

Radiology is an important diagnostic instrument in avian medicine, but standard measurement ranges for the objective evaluation of radiographs of birds are rare. To establish radiographic reference ranges for the critically endangered Spix's macaw (Cyanopsitta spixii), we measured radiographic silhouettes of the heart, liver, kidneys, spleen, proventriculus, and keel of the sternum on 29 radiographs taken under standardized conditions in adult and juvenile, clinically healthy birds. Ratios were determined for the proventricular diameter-to-keel height, the width of the heart to the width of the thorax, and for the "hourglass shape" (ratio of the width of the heart to the width of the liver). No significant differences were found between the sexes among the adult birds. Compared with adult birds, juvenile females had a significantly larger heart width (19.8 +/- 1.4 mm versus 21.2 +/- 0.7 mm), ratio of the heart width to the thorax width (0.86 +/- 0.08 versus 0.94 +/- 0.09), and horizontal width of the spleen (7.7 +/- 0.6 mm versus 8.5 +/- 0.4 mm). Results of radiographic measurements in the Spix's macaws were comparable to those published from other psittacine species. These reference ranges will facilitate a more objective radiographic evaluation of captive Spix's macaws. PMID:22458180

Rettmer, Helen; Deb, Amrita; Watson, Ryan; Hatt, Jean-Michel; Hammer, Sven

2011-12-01

5

Use of Cathorops spixii as bioindicator of pollution of trace metals in the Santos Bay, Brazil.  

PubMed

In the present study Cathorops spixii, was evaluated as a bioindicator fish for trace metal pollution. Concentrations of cobalt (Co), iron (Fe), selenium (Se) and zinc (Zn) were determined by Instrumental Neutron Activation Analysis in liver. Mercury (Hg) and methyl-mercury (MeHg) were analyzed by Cold Vapor Atomic Absorption Spectrometry in muscles and livers. High concentrations of Co, Fe, Se and Zn were observed in C. spixii from Santos Bay in comparison to fish collected in a non-polluted site in the same Brazilian coast. These trace metal concentrations were out of the permissible levels for human consumption. Although, Hg and MeHg levels were low, the C. spixii could still be used as an effective bioindicator to observe trace metal behaviors in the environment in function of the bioaccumulation process observed mainly by other analyzed trace metals. Thus, the use of this species is strongly recommended to monitor the effects and behavior of trace metal pollution in aquatic ecosystems in Brazil due to its bioaccumulation function. PMID:19404739

Azevedo, J S; Fernandez, W S; Farias, L A; Fávaro, D T I; Braga, E S

2009-07-01

6

Analysis of the inflammatory reaction induced by the catfish (Cathorops spixii) venoms.  

PubMed

Cathorops spixii is one of the most abundant venomous fish of the southeastern coast of the State of São Paulo, and consequently causes a great part of the accidents seen there. The accidents affect mainly fishermen, swimmers and tourists and are characterized by punctiform or wide wounds, erythema, edema, pain, sudoresis, indisposition, fever, nausea, vomiting and secondary infection. The objective of this work was to characterize the inflammatory response induced in mice by both venoms (mucus and sting) of the catfish C. spixii. Our results demonstrated that both venoms induced a great number of rolling and adherent leukocytes in the post-capillary venules of cremaster muscle of mice, and an increase in the vascular permeability in peritoneal cavity. Mucus induced the recruitment of neutrophils immediately after injection followed later by macrophage infiltration. In contrast, the cellular infiltration elicited by sting venom was rapidly resolved. The peritonitis reaction provoked by venoms was characterized by cytokine (IL-6), chemokines (MCP-1 and KC) or lipid mediator (LTB4) production in the peritoneal cavity. The macrophages from 7-day mucus venom-induced exudates upon in vitro mucus venom stimulation, expressed CD11c x MHC class II and release bioactive IL-12p70. On the other hand, sting venom-elicited peritoneal macrophages lost the ability to differentiate into dendritic cells, following re-stimulation in vitro with sting venom, they do not express CD11c, nor do they exhibit sufficient levels of MHC class II. In conclusion, both types of venoms (mucus or sting) promote inflammatory reaction with different profiles, and the inflammatory reaction induced by the first was characterized by antigen persistence in peritoneal cavity that allowed the activation of phagocytic cells with capacity of antigenic presentation. PMID:17321559

Junqueira, Marcos Emerson Pinheiro; Grund, Lidiane Zito; Orii, Noêmia M; Saraiva, Tânia Cristina; de Magalhães Lopes, Carlos Alberto; Lima, Carla; Lopes-Ferreira, Mônica

2007-06-01

7

Assessment of trace metal levels in catfish (Cathorops spixii) from Sal River estuary, Aracaju, state of Sergipe, northeastern Brazil.  

PubMed

The concentrations of cadmium, copper, nickel, zinc, and lead were determined in the catfish (Cathorops spixii) from the Sal River estuary, Brazil, to evaluate the potential role of domestic and industrial effluents released without treatment on the quality of the estuarine environment with consequences to fish resources. Muscle, liver, and kidney samples were analyzed for trace metal composition by flame atomic absorption spectrophotometry. The mean concentration (microg/g wet weight) of trace metals in the tissues of C. spixii were as follows: cadmium = 1.65, 2.81, and 0.71 microg/g; copper = 29.07, 4.38, and 3.40 microg/g; zinc = 229, 312, and 15.57 microg/g; nickel = 1.22, 1.04, and 117 microg/g; and lead = 7.09, 10.77, and 11.18 microg/g. The results show that metal accumulation in organs indicates the difference between them. The results showed high concentrations of copper, zinc, nickel, lead, and cadmium in the Cathorops spixii compared with the maximum values registered from fish in studies reported in other coastal regions of Brazil. PMID:21214023

Barbieri, Edison; Passos, Elisangela de Andrade; Aragão, Kennedy Alexandre Sousa; Santos, Danielle Barros; Garcia, Carlos Alexandre Borges

2010-12-01

8

Specialization of the sting venom and skin mucus of Cathorops spixii reveals functional diversification of the toxins.  

PubMed

Cathorops spixii is the most common venomous fish on the Brazilian coast. Apart from the involvement with defense against pathogens, the possible contribution of skin mucus components to the development of injuries caused by venomous fish species has not been investigated. Thus, the present study was conducted to gain a better understanding of the peptide and protein components of fish skin mucus and the sting venom from the catfish C. spixii. Our results show that sting venom and skin mucus have distinct constituents that distinguished them like structural proteins, chaperones, ion transport, carbohydrate metabolism, oxidoreductase, cell cycle and protein binding present in sting venom and like tropomyosin 3 isoform 2 and energy metabolim proteins in skin mucus. But in a group of common 13 proteins we identified and isolated a WAP65 protein. The peptide fractions caused more harmful effects, such as venular stasis, hemorrhage and changes in the arteriolar wall diameter, and the protein fractions produced a typical inflammatory process in post-capillary venules. And finally we showed for the first time the presence WAP65 in sting venom and skin mucus of C. spixii using LC/MS/MS and also we purified this protein in the sting venom. Wap65 shows inflammatory action, working at different doses inducing an increase in the number of leukocytes rolling and adhering to the endothelium. PMID:22381657

Ramos, Anderson Daniel; Conceição, Katia; Silva, Pedro Ismael; Richardson, Michael; Lima, Carla; Lopes-Ferreira, Mônica

2012-05-01

9

Encephalitozoon infections in Rodentia and Soricomorpha in Japan.  

PubMed

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. PMID:24060383

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

2013-11-15

10

Biomarkers of exposure to metal contamination and lipid peroxidation in the benthic fish Cathorops spixii from two estuaries in South America, Brazil.  

PubMed

Biomarkers as lipid peroxidation, metallothionein and delta-aminolevulinic acid dehydratase were determined in Cathorops spixii to compare the biological responses of this fish from estuaries with distinct anthropogenic influence. Three areas were selected in two estuaries in accordance with the levels of contamination for the polluted (Santos/São Vicente) and with the hydrodynamic characteristics for the non-polluted (Cananéia) estuary. Water characteristics and mercury levels in C. spixii confirmed a high human influence in the polluted system. In general, the biomarkers showed differences between the estuaries, suggesting disturbances in the specific cell mechanisms due to the presence of multiple xenobiotics in the contaminated system. Therefore, these biomarkers are recommended to promote more accurate information about the exposure to pollutants. Additionally, the study of the effect of the multiple xenobiotics on resident species such as the benthic fish C. spixii can favor a better assessment of the environmental quality of these systems. PMID:19603268

Azevedo, J S; Serafim, A; Company, R; Braga, E S; Fávaro, D I; Bebianno, M J

2009-11-01

11

Bioaccumulation of butyltins and liver damage in the demersal fish Cathorops spixii (Siluriformes, Ariidae).  

PubMed

The toxicity of butyltin compounds (BTs), mainly tributyltin (TBT), has been reported in different organisms. However, such an analysis in fish after field exposure with reference to the related biomarkers has not been commonly observed in the literature. This study presents the uptake of BTs in the liver of a neotropical marine catfish Cathorops spixii in Paranagua Bay, an important estuarine system located in southern Brazil. Two different areas, close to and distant from the harbor, were used for chemical analysis evaluation of hepatotoxicity through genetic, enzymatic, and histopathological biomarkers. The presence of polycyclic aromatic hydrocarbons in bile was also considered as a biomarker. The results showed a significant relationship between TBT levels and the inhibition of biotransformation enzymes and high occurrence of melanomacrophages in fish collected close to the harbor site. These effects were linked to the absence of TBT metabolites in the liver. In the second site, the presence of DBT was associated with an increase in EROD and GST activity. The larger amount of DNA damage as well as the highest oxidative stress was noted in fish from the less TBT-polluted area, where DBT and bile PAHs occurred. These findings showed different impact levels due to or increased by the chronic exposure of biota to BTs. PMID:24217970

Dos Santos, Dayana Moscardi; Santos, Gustavo Souza; Cestari, Marta Margarete; de Oliveira Ribeiro, Ciro Alberto; de Assis, Helena Cristina Silva; Yamamoto, Flavia; Guiloski, Izonete Cristina; de Marchi, Mary Rosa Rodrigues; Montone, Rosalinda Carmela

2014-02-01

12

44(896):5963 Sciurus spadiceus (Rodentia: Sciuridae)  

E-print Network

brunneo-niger Gray, 1867:429. Type locality ``Brazil (Castelnau).'' Sciurus castus Thomas, 1903:488. Type44(896):59­63 Sciurus spadiceus (Rodentia: Sciuridae) R. NATHAN GWINN, JOHN L. KOPROWSKI, ROSA R@email.arizona.edu (RRJ); mmerrick@email.arizona.edu (MJM) Abstract: Sciurus spadiceus Olfers, 1818, is a sciurid commonly

Hayssen, Virginia

13

Population Dynamics and Diet of the Madamango Sea Catfish Cathorops spixii (Agassiz, 1829) (Siluriformes: Ariidae) in a Tropical Bight in Southeastern Brazil  

PubMed Central

The madamango sea catfish, Cathorops spixii (Siluriformes: Ariidae), is often among the most abundant fishes on the South American Atlantic coast. In the present study, conducted in shallow, non-estuarine coastal areas of Caraguatatuba Bight in southeastern Brazil, collections of this species, the most abundant member of the ichthyofauna, included primarily medium-sized individuals, indicating that the area may play a specific role in their development. Although studies of the local ichthyofauna have been much neglected, the area is economically important and its ecological significance is undervalued. This study primarily treats habitat use by C. spixii, assessing certain population parameters and the dietary composition. Monthly samples were taken from August 2003 through October 2004, with three trawls in two areas, corresponding to depths of about 1 to 4 m. The catfish showed two main peaks of abundance in the area, in April/May and July 2004. A mode around 9 cm SL persisted through time, and the entrance of younger recruits peaked from January to April. The low estimate for body-growth parameters (K?=?0.16) corroborates some K-strategist characteristics of the species. The asymptotic length was 27.3 cm SL and total mortality (Z) was 1.01 yr?1. Cathorops spixii showed an omnivorous feeding habit, preying mainly upon polychaetes, copepods and bivalves, with considerable seasonality in its diet. PMID:24282575

Denadai, Márcia; Pombo, Maíra; Santos, Flávia Borges; Bessa, Eduardo; Ferreira, Adriana; Turra, Alexander

2013-01-01

14

Population dynamics and diet of the madamango Sea catfish Cathorops spixii (Agassiz, 1829) (Siluriformes: Ariidae) in a tropical bight in Southeastern Brazil.  

PubMed

The madamango sea catfish, Cathorops spixii (Siluriformes: Ariidae), is often among the most abundant fishes on the South American Atlantic coast. In the present study, conducted in shallow, non-estuarine coastal areas of Caraguatatuba Bight in southeastern Brazil, collections of this species, the most abundant member of the ichthyofauna, included primarily medium-sized individuals, indicating that the area may play a specific role in their development. Although studies of the local ichthyofauna have been much neglected, the area is economically important and its ecological significance is undervalued. This study primarily treats habitat use by C. spixii, assessing certain population parameters and the dietary composition. Monthly samples were taken from August 2003 through October 2004, with three trawls in two areas, corresponding to depths of about 1 to 4 m. The catfish showed two main peaks of abundance in the area, in April/May and July 2004. A mode around 9 cm SL persisted through time, and the entrance of younger recruits peaked from January to April. The low estimate for body-growth parameters (K = 0.16) corroborates some K-strategist characteristics of the species. The asymptotic length was 27.3 cm SL and total mortality (Z) was 1.01 yr(-1). Cathorops spixii showed an omnivorous feeding habit, preying mainly upon polychaetes, copepods and bivalves, with considerable seasonality in its diet. PMID:24282575

Denadai, Márcia; Pombo, Maíra; Santos, Flávia Borges; Bessa, Eduardo; Ferreira, Adriana; Turra, Alexander

2013-01-01

15

Molecular Phylogeny of Rodentia, Lagomorpha, Primates, Artiodactyla, and Carnivora and Molecular Clocks  

Microsoft Academic Search

Phylogenetic analysis of DNA sequences from primates, rodents, lagomorphs, artiodactyls, carnivores, and birds strongly suggests that the order Rodentia is an outgroup to the other four mammalian orders and that Artiodactyla and Carnivora belong to a superordinal clade. Further, there is strong evidence against the Glires concept, which unites Lagomorpha and Rodentia. The radiation among Lagomorpha, Primates, and Artiodactyla-Carnivora is

Wen-Hsiung Li; Manolo Gouy; Paul M. Sharp; Colm O'Huigin; Yau-Wen Yang

1990-01-01

16

A new species of spiny pocket mouse (Rodentia: Heteromyidae: Heteromys) from northwestern Costa Rica  

E-print Network

Recent taxonomic works have recognized only two species of spiny pocket mice of the genus Heteromys (Rodentia: Heteromyidae) from Costa Rica. Within Costa Rica, the widespread H. desmarestianus is considered to occur ...

Anderson, Robert P.; Timm, Robert M.

2006-03-01

17

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

PubMed

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. PMID:24782088

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

2014-01-01

18

Heterochromatin and the DNA content in Geomys attwateri and G. breviceps (Rodentia: Geomyidae)  

E-print Network

HETEROCHROMATIN AND DNA CONTENT IN GEO11YS ATTWATERI AND G. BREVICEPS (RODENTIA:GEOMYIDAE) A Thesis by DAVID WINSTON BURTON Submitted to the Graduate College of Texas ARM University in partial fulfillment of the requirements for the degree... of MASTERS OF SCIENCE December 1986 Major Subject: Wildlife and Fisheries Science HETEROCHROMATIN AND THE DNA CONTENT IN GEOMTS ATTWATERI AND G. BREVICEPS (RODENTIA:GEQMYIDAE) A Thesis by DAVID WINSTON BURTON Approved as to style and content: John W...

Burton, David Winston

1986-01-01

19

Acariform mites (Acariformes) - permanent symbionts of Hapalomys delacouri Thomas (Rodentia, Muridae) in Vietnam  

PubMed Central

Abstract Two new species of parasitic acariform mites (Acariformes) are described from the Delacour’s marmoset rat Hapalomys delacouri Thomas (Rodentia: Muridae) in Vietnam: Afrolistrophorus (Afrolistrophorus) hapalomys sp. n. (Listrophoridae) and Radfordia (Radfordia) mirabilis sp. 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). PMID:25561857

Bochkov, Andre V.; Abramov, Alexei V.

2014-01-01

20

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

NASA Astrophysics Data System (ADS)

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.

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

21

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

PubMed

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. PMID:20549178

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

22

The south-eastern house mouse Mus musculus castaneus (Rodentia: Muridae) is a polytypic subspecies  

E-print Network

The south-eastern house mouse Mus musculus castaneus (Rodentia: Muridae) is a polytypic subspecies processes and achieve sound evolutionary comparisons. A case in point is the house mouse Mus musculus musculus domesticus and Mus musculus musculus constitute genetically well- characterized homogeneous

Nachman, Michael

23

Early Miocene cricetids (Rodentia) from the Junggar basin (Xinjiang, China) and their biochronological implications  

Microsoft Academic Search

Among the 14small mammal species from the early Miocene locality of the northern area of the Junggar basin (northern Xinjiang, China), four species are cricetids (Rodentia): unnamed species of Cricetodon and Eumyarion, and two new species, Karydomys debruijni nov. sp. and Megacricetodon beijiangensis nov. sp. Some aspects of the morphology of Cricetodon sp. are shared by Eucricetodon from the late

Olivier Maridet; Wen-Yu Wu; Jie Ye; Shun-Dong Bi; Xi-Jun Ni; Jin Meng

24

Marmota caligata (Rodentia: Sciuridae) JANET K. BRAUN, T. SCOTT EATON, JR., AND MICHAEL A. MARES  

E-print Network

Marmota caligata (Rodentia: Sciuridae) JANET K. BRAUN, T. SCOTT EATON, JR., AND MICHAEL A. MARES 73072, USA; mamares@ou.edu (MAM) Abstract: Marmota caligata (Eschscholtz, 1829), a large ground squirrel.1644/884.1 w w w . m a m m a l o g y . o r g Marmota caligata (Eschscholtz, 1829) Hoary Marmot Arctomys

Hayssen, Virginia

25

Topografia do cone medular no ratão-do-banhado ( Myocastor coypus Molina, 1782 - Rodentia: Mammalia)  

Microsoft Academic Search

Topography of the medullar cone in nutria (Myocastor coypus Molina, 1782 - Rodentia: Mammalia). Aiming to investigate the topography of the medullar cone, ten adult nutria (Myocastor coypus), eight male and two female, were previously fixed in 10% aqueous formalin solution, maintained in similar solution and dissected. After the dissection the following data were noted: a) the medullar cone apex

Gilberto Valente Machado; Josy Alvarenga Cal; Arlei José Birck

26

Patterns of phenotypic and genetic variation in three species of endemic Mesoamerican Peromyscus (Rodentia: Cricetidae)  

E-print Network

(Rodentia: Cricetidae) NICTE´ ORDO´ N~ EZ-GARZA,* JOHN O. MATSON, RICHARD E. STRAUSS, ROBERT D. BRADLEY species group (P. grandis, P. guatemalensis, and P. zarhynchus) were characterized morphologically morphologically and genetically distinct units. Our analyses suggest that P. grandis and P. guatemalensis are more

Strauss, Richard E.

27

Peromyscus schmidlyi (Rodentia: Cricetidae) NICTE ORDO N~ EZ-GARZA AND ROBERT D. BRADLEY  

E-print Network

. Photographed by Robert D. Bradley, August 2004. MAMMALIAN SPECIES 43(872):31­36 #12;However, P. schmidlyiPeromyscus schmidlyi (Rodentia: Cricetidae) NICTE´ ORDO´ N~ EZ-GARZA AND ROBERT D. BRADLEY-oak forest regions of the northern and central portions of the Sierra Madre Occidental. P. schmidlyi

Hayssen, Virginia

28

Tamias umbrinus (Rodentia: Sciuridae) JANET K. BRAUN, AUBREY A. JOHNSON, AND MICHAEL A. MARES  

E-print Network

Tamias umbrinus (Rodentia: Sciuridae) JANET K. BRAUN, AUBREY A. JOHNSON, AND MICHAEL A. MARES Sam; aubreyana009@yahoo.com (AAJ); mamares@ou.edu (MAM) Abstract: Tamias umbrinus Allen, 1890, a medium.1644/889.1 w w w . m a m m a l o g y . o r g Tamias umbrinus Allen, 1890 Uinta Chipmunk Tamias umbrinus Allen

Hayssen, Virginia

29

Biochemical changes in the liver and gill of Cathorops spixii collected seasonally in two Brazilian estuaries under varying influences of anthropogenic activities.  

PubMed

In order to understand environmental health by the use of a bioindicator species in estuaries, biochemical responses observed in the catfish Cathorops spixii such as catalase (CAT), glutathione-S-transferase (GST), lipid peroxidation (LPO) and acetylcholinesterase (AChE) were evaluated in liver and muscle. Furthermore, histological changes were also verified in liver and gills preparations. Fish were collected in three sites of the Santos-São Vicente estuary located at São Paulo (Brazil), subjected to varying levels of inputs of pollutants. For a reference site, specimens were sampled at Cananéia estuary at southern coast of São Paulo, a region with low anthropogenic influence. In general, no significant seasonal differences in antioxidant enzymes and lipid peroxidation responses were found in the organisms from the Cananéia estuary. However, in the polluted estuary (Santos-São Vicente), biochemical responses were observed by increases in GST hydroperoxides and decreases in AChE activities in the summer. Inhibition of AChE expression in fish from different areas of the Santos-São Vicente estuary in the summer was also found and can indicate neurotoxic effects in these organisms. Histopathological observation of gill and liver showed severe lesions, such as lamellar fusion and necrosis. PMID:23880419

Azevedo, J S; Braga, E S; Silva de Assis, H C; Oliveira Ribeiro, C A

2013-10-01

30

An assessment of acute biomarker responses in the demersal catfish Cathorops spixii after the Vicuña oil spill in a harbour estuarine area in Southern Brazil.  

PubMed

The Vicuña oil tanker exploded in Paranaguá Bay (South of Brazil), during methanol unloading operations in front of Paranaguá Harbour, on November 15th, 2004, releasing a large amount of bunker oil and methanol. Two weeks after the accident, the acute effects of the Vicuña Oil Spill (VOS) were evaluated in the demersal catfish Cathorops spixii, comparing a contaminated (at the spill site) and a reference site inside the Bay. Data were compared to previous measurements, taken before the accident, in the same species, from the same sites. The physiological biomarkers were the ones that best reflected acute effects of the spill: plasma osmolality, chloride, calcium, magnesium, and potassium. Morphological (liver and gill histopathology) and genetic (piscine micronucleus and DNA strand breaks) biomarkers revealed that damage was already present in fishes from both reference and contaminated sites inside the Bay. Thus, the reference site is not devoid of contamination, as water circulation tends to spread the contaminants released into other areas of the Bay. Acute field surveys of oil spill effects in harbour areas with a long history of contamination should thus be viewed with caution, and whenever possible previous evaluations should be considered for proper appraisal of biomarker sensitivity, especially in mobile bioindicators such as fish. PMID:18478347

Katsumiti, A; Domingos, F X Valdez; Azevedo, M; da Silva, M D; Damian, R C; Almeida, M I M; de Assis, H C Silva; Cestari, M M; Randi, M A F; Ribeiro, C A Oliveira; Freire, C A

2009-05-01

31

Two new karyotypes and bandings in Microtus mandarinus faeceus (Rodentia).  

PubMed

Here we report our study on two new karyotypes and C-bandings of M. m. faeceus. Our study shows that there are polymorphisms in the X chromosome of M. m. faeceus (Rodentia), which exibitsubtelocentric X(ST), metacentric X(M) and submetacentric X(SM) patterns, respectively. One new karyotype formula is: 2n = 49 = 4sm + 42t + 1m + XX (sm,sm), and the sex chromosomes are: X(M) X(SM); The other new karyotype formula is: 2n = 50 = 4sm + 43t + 1m + XX (sm,sm), and the sex chromosomes are: X(SM)X(SM). One C-banding karyotype formula is: 2n = 49 = 4sm + 44t + X(st)0, and the sex chromosome is: X(ST)O and the other C-banding karyotype formula is: 2n = 50 = 4sm + 44t + XY(m,t), and the sex chromosomes are: X(M) Y. PMID:20626766

Liu, Huanmin; Yan, Nan; Zhu, Bicai

2010-06-01

32

Microtus guentheri (Danford & Alston) (Rodentia, Mammalia) : a bioindicator species for estimation of the influence of polymetal dust emissions  

Microsoft Academic Search

Chemical pollution of ecosystems resulting from human activity is an ecological factor in the living world, affecting individuals, populations, communities and ecosystems as a whole. This laboratory investigation studied the toxic effects of polymetal ferosilicic dust on Microtus guentheri (Rodentia, Mammalia), measuring path- ological changes in blood components (haemoglobin, erythrocyte, leucocyte and platelets number, erythrocyte sedi- mentation rate (ESR) and

Tsenka Chassovnikarova; Roumiana Metcheva; Krastio Dimitrov

33

Ecological and histological aspects of tail loss in spiny mice (Rodentia: Muridae, Acomys) with a review of its occurrence  

E-print Network

Ecological and histological aspects of tail loss in spiny mice (Rodentia: Muridae, Acomys tailed and tail-less spiny mice, suggesting an advantage to tail-less individuals. Histological sections use. Key words: spiny mice, tail loss, autotomy, histology, predation INTRODUCTION Autotomy, the loss

Dayan, Tamar

34

Geographic variation in the white-throated woodrat, Neotoma albigula (Rodentia: Muridae) from New Mexico, Texas, and northern Mexico  

E-print Network

GEOGRAPHIC VARIATION IN THE WHITE-THROATED WOODRAT, NEOTOMA ALBIGULA (RODENTIA: MURIDAE) FROM NEW MEXICO, TEXAS, AND NORTHERN MEXICO A Thesis by DUKE SANFORD ROGERS Submitted to the Graduate College of Texas AAM University in partial... MEXICO A Thesis by DUKE SANFORD ROGFRS Ap roved as to style and content: Cha' an of Committ ) Head of Department ember Member August 1979 ABSTRACT Geographic variation in the White-throated Woodrat, N t ~sbi 1 )Rd ti;Muid )fo N M io, l...

Rogers, Duke Sanford

1979-01-01

35

A new Eimeria species (Apicomplexa: Eimeriidae) infecting Onychomys species (Rodentia: Muridae) in New Mexico and Arizona.  

PubMed

Fecal samples from 3 species of Onychomys (Rodentia: Muridae) captured in New Mexico and Arizona were examined for coccidia. Six of the 59 (10%) were infected with a new species of Eimeria. Sporulated oocysts (n = 105) of this new species are subspheroidal, 17.4 x 16.1 (14-21 x 13-19) microm, with ellipsoidal sporocysts 10.4 x 5.7 (9-12 x 5-8) microm. This species occurred in 3 of 24 (13%) Onychomys arenicola, 2 of 31 (6%) Onychomys leucogaster from New Mexico, and 1 of 4 (25%) Onychomys torridus from Arizona. Isolates recovered from O. leucogaster and O. torridus were inoculated into O. leucogaster (n = 5) and produced infections with a prepatent period of 7 days and a patent period of 7-23 days. PMID:9920315

Hnida, J A; Wilson, W D; Duszynski, D W

1998-12-01

36

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

PubMed

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. PMID:22327013

Upham, Nathan S; Patterson, Bruce D

2012-05-01

37

Mites of the subgenus Neotomobia n. subg. (Acariformes: Myobiidae: Radfordia), parasites of the subfamily Neotominae (Rodentia: Cricetidae).  

PubMed

A new subgenus Neotomobia n. subg. (Acariformes: Myobiidae: Radfordia) is established for species parasitising rodents of the subfamily Neotominae (Rodentia: Cricetidae): Radfordia subuliger Ewing, 1938 (type-species), Radfordia eremici Fain & Bochkov, 2002, Radfordia neotomae Jameson & Whitaker, 1975 and Radfordia hamiltoni Jameson & Whitaker, 1975. Three new species are described: Radfordia peromyscus n. sp. from Peromyscus megalops Merriam from Mexico, Radfordia onychomys n. sp. from Onychomys leucogaster (Wied-Neuwied) from the USA and Radfordia megadontomys n. sp. from Megadontomys thomasi (Merriam) from Mexico. PMID:25204596

Bochkov, Andre V; Guzmán-Cornejo, Carmen

2014-10-01

38

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

PubMed Central

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

2010-01-01

39

Hidden heterochromatin: Characterization in the Rodentia species Cricetus cricetus, Peromyscus eremicus (Cricetidae) and Praomys tullbergi (Muridae)  

PubMed Central

The use of in situ restriction endonuclease (RE) (which cleaves DNA at specific sequences) digestion has proven to be a useful technique in improving the dissection of constitutive heterochromatin (CH), and in the understanding of the CH evolution in different genomes. In the present work we describe in detail the CH of the three Rodentia species, Cricetus cricetus, Peromyscus eremicus (family Cricetidae) and Praomys tullbergi (family Muridae) using a panel of seven REs followed by C-banding. Comparison of the amount, distribution and molecular nature of C-positive heterochromatin revealed molecular heterogeneity in the heterochromatin of the three species. The large number of subclasses of CH identified in Praomys tullbergi chromosomes indicated that the karyotype of this species is the more derived when compared with the other two genomes analyzed, probably originated by a great number of complex chromosomal rearrangements. The high level of sequence heterogeneity identified in the CH of the three genomes suggests the coexistence of different satellite DNA families, or variants of these families in these genomes. PMID:21637647

2009-01-01

40

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

PubMed

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. PMID:20379801

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; Yi?it, Nuri; Ferguson-Smith, Malcolm A; Yang, Fengtang; Graphodatsky, Alexander S

2010-06-01

41

Extended Longevity of Reproductives Appears to be Common in Fukomys Mole-Rats (Rodentia, Bathyergidae)  

PubMed Central

African mole-rats (Bathyergidae, Rodentia) contain several social, cooperatively breeding species with low extrinsic mortality and unusually high longevity. All social bathyergids live in multigenerational families where reproduction is skewed towards a few breeding individuals. Most of their offspring remain as reproductively inactive “helpers” in their natal families, often for several years. This “reproductive subdivision” of mole-rat societies might be of interest for ageing research, as in at least one social bathyergid (Ansell's mole-rats Fukomys anselli), breeders have been shown to age significantly slower than non-breeders. These animals thus provide excellent conditions for studying the epigenetics of senescence by comparing divergent longevities within the same genotypes without the inescapable short-comings of inter-species comparisons. It has been claimed that many if not all social mole-rat species may have evolved similar ageing patterns, too. However, this remains unclear on account of the scarcity of reliable datasets on the subject. We therefore analyzed a 20-year breeding record of Giant mole-rats Fukomys mechowii, another social bathyergid species. We found that breeders indeed lived significantly longer than helpers (ca. 1.5–2.2fold depending on the sex), irrespective of social rank or other potentially confounding factors. Considering the phylogenetic positions of F. mechowii and F. anselli and unpublished data on a third Fukomys-species (F. damarensis) showing essentially the same pattern, it seems probable that the reversal of the classic trade-off between somatic maintenance and sexual reproduction is characteristic of the whole genus and hence of the vast majority of social mole-rats. PMID:21533255

Dammann, Philip; Šumbera, Radim; Maßmann, Christina; Scherag, André; Burda, Hynek

2011-01-01

42

A finding of the XX\\/XY1Y2 sex-chromosome system in Taterillus arenarius(Gerbillinae, Rodentia) and its phylogenetic implications  

Microsoft Academic Search

A chromosome banding study (R- and C-bands) of a male Taterillus arenarius (Rodentia, Gerbillinae) specimen from Mauritania revealed the presence of an XX\\/XY1 Y2 sex-chromosome system in the karyotype, as found previously in three other congeneric species. This finding allowed us to resolve the phylogenetic affinities of this species within the genus and to propose an evolutionary scenario leading to

V. Volobouev; L. Granjon

1996-01-01

43

Comparative cytogenetic study of two sister species of Iberian ground voles, Microtus (Terricola) duodecimcostatus and M. (T.) lusitanicus (rodentia, cricetidae).  

PubMed

The two Iberian species of pine voles, Microtus (Terricola) duodecimcostatus and M. (T.) lusitanicus of the subfamily Arvicolinae (Cricetidae, Rodentia), were compared after G- and C-banding and chromosomal mapping of ribosomal RNA genes (rDNA), telomeric repeats, and satellite DNA Msat-160. Notwithstanding their close relationship (one sister group in phylogenetic analyses) and sharing of the diploid and fundamental chromosome numbers, the 2 species show notable differences in the sex chromosome morphology, the number and distribution of rDNA sites, constitutive heterochromatin and satDNA patterns. The only telomeric repeats showed normal, all-telomeric, distribution in karyotypes of both species. The data are discussed with regard to interspecific and intrageneric variation of the analyzed characters and the chromosomal evolution in the genus Microtus. PMID:21042006

Gornung, E; Castiglia, R; Rovatsos, M; Marchal, J A; Díaz de la Guardia-Quiles, R; Sanchez, A

2011-01-01

44

Characteristics of the larval Echinococcus vogeli Rausch and Bernstein, 1972 in the natural intermediate host, the paca, Cuniculus paca L. (Rodentia: Dasyproctidae).  

PubMed

In Colombia, the natural intermediate host of Echinococcus vogeli Rausch and Bernstein, 1972 is the paca, Cuniculus paca L. (Rodentia: Dasyproctidae). The larval cestode develops in the liver of the host, where it usually is situated superficially, partly exposed beneath Glisson's capsule. The infective larva consists of a subspherical to asymmetrical, fluid-filled vesicle, up to 30 mm in diameter, enclosed by a thick laminated membrane. It typically contains numerous chambers, often interconnected, produced by endogenous proliferation of germinal and laminated tissue, within which brood capsules arise in an irregular pattern from the germinal layer. Invasive growth by means of exogenous proliferation, typical of infections in man, was not observed in the natural intermediate host. The development of the larval cestode is described on the basis of material from pacas, supplemented by observations on early-stage lesions in experimentally infected nutrias, Myocastor coypus (Molina) (Rodentia: Capromyidae). The tissue response is characterized for early-stage, mature (infective), and degenerating larvae in the comparatively long-lived intermediate host. In addition to previously reported differences in size and form of rostellar hooks, other morphologic characteristics are defined by which the larval stage of E. vogeli is distinguished from that of E. oligarthrus (Diesing, 1863). Pathogenesis by the larval E. vogeli in man, like that by the larval E. multilocularis Leuckart, 1863, is the consequence of atypical proliferation of vesicles attributable to parasite-host incompatibility. PMID:7283003

Rausch, R L; D'Alessandro, A; Rausch, V R

1981-09-01

45

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

USGS Publications Warehouse

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.

Fisher, Robert D.; Ludwig, Craig A.

2012-01-01

46

Tick infestations of the eastern cottontail rabbit (Sylvilagus floridanus) and small rodentia in northwest Alabama and implications for disease transmission.  

PubMed

Studies were conducted over a four-county area of northwest Alabama to determine the association of eastern cottontail rabbits with Dermacentor variabilis, the eastern United States vector of Rocky Mountain spotted fever. A secondary objective was to compare infestations of this tick on rabbits with infestations on commonly encountered rodent species as a means of determining the relative importance of each in the disease transmission cycle. These epidemiologic surveys were conducted in response to reported fatal cases of Rocky Mountain Spotted Fever in two counties of the study area. From 202 eastern cottontail rabbits, 3,956 ticks were collected. Of this total, 79.87% were Haemphysalis leporispalustris, 9.15% Amblyomma americanum, 8.22% Ixodes dentatus, and 2.76% D. variabilis. Only immature stages of D. variabilis were collected from cottontail rabbits. Ticks were collected on rabbits in all months except November, and only one specimen was taken in January. Based on the average number of ticks per host collected in each month, April was the peak month for D. variabilis and I. dentatus. High values for H. leporispalustris also occurred at this time, but even higher values occurred in October and December. The heaviest infestation of A. americanum occurred during the month ofAugust and coincides with the activity period for the larvae of this species. Two hundred sixty-nine of the smaller Rodentia, comprising 13 species, yielded 264 ticks, all D. variabilis, and all but two were immature stages. Five rodent species, Microtus ochragaster Orozomys palustris, Peromyscus gossypinus, Peromyscus leucopus, and Sigmodon hispidus accounted for 95.83% of the ticks collected, and appeared to be preferred hosts for D. variabilis; all five had higher infestation levels per host than did the eastern cottontail rabbit. Data on host relationships in association with seasonal activity are presented. PMID:16599149

Cooney, Joseph C; Burgdorfer, Willy; Painter, Martin K; Russell, Cynthia L

2005-12-01

47

Biting performance and skull biomechanics of a chisel tooth digging rodent (Ctenomys tuconax; Caviomorpha; Octodontoidea).  

PubMed

Biting performance is a key factor in vertebrate groups possessing particular food habits. In subterranean rodents that use the incisors as a digging tool, apart from requirements related to gnawing abrasive diets, the force exerted at the incisors tips must be sufficient to break down soils that are often exceedingly compact. The subterranean genus Ctenomys diversified in the southern portion of South America closely associated with the relatively open environments that characterize that region. This genus is considered a "claw and chisel tooth digger," that is, during the excavation of their galleries, the animals break down the soil with both the fore-claws and the incisors. We report here measurements of in vivo bite force in one of the largest species of the genus, C. tuconax, which occupies highland grasslands with compacted soils. We document the combined use of claws and incisors observed under field conditions, also providing measurements of soil compaction in the habitat occupied by this species. We report estimates of bite force at the level of the incisors and cheek teeth calculated from the physiological cross-sectional area of jaw muscles. To this aim, anatomical and biomechanical analyses of the mandibular apparatus were performed in preserved specimens. We found that C. tuconax bites with a higher force than expected for a mammal of its size. To assess anatomical correlates of biting performance, the morphology of the skull and jaw, and incisor second moment of area were compared with those of other caviomorph rodents with different lifestyle. PMID:23203312

Becerra, Federico; Casinos, Adrià; Vassallo, Aldo Iván

2013-02-01

48

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

USGS Publications Warehouse

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.

Fisher, Robert D.; Ludwig, Craig A.

2014-01-01

49

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

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. PMID:21658923

Schmidt, André

2011-06-01

50

A new species of Litomosoides Chandler, 1931 (Nematoda: Filarioidea) from the long-nosed hocicudo Oxymycterus nasutus Waterhouse (Rodentia: Cricetidae) in Uruguay.  

PubMed

A new species of Litomosoides Chandler, 1931 was collected from the abdominal cavity of Oxymycterus nasutus Waterhouse (Rodentia: Cricetidae) in the grassland of the Departamento Rocha, Uruguay. Litomosoides nasuti n. sp. belongs to the 'sigmodontis group', and is characterised by: salient amphids; two ventral and one dorsal labial papillae, but no cephalic papillae; a buccal capsule with a transparent anterior segment and an annular asymmetrical thickening; a muscular oesophagus; a bottle-shaped buccal cavity; the male with symmetrically situated cloacal papillae (one pair ad-cloacal and three pairs post-cloacal); phasmids displaced laterally to the longitudinal axis; and microfilariae without terminal nuclei in the tail tip. It resembles five known species; three of which have been recovered from Oxymycterus spp. in neighbouring countries. However, the new species can be differentiated from L. sigmodontis Chandler, 1931 by the shape and size of the buccal capsule; from L. navonae Notarnicola, 2005 by the muscular oesophagus; from L. legerae Bain, Petit & Berteaux, 1980 by the length of the oesophagus and the cephalic papillae; from L. anguyai Notarnicola, Bain & Navone, 2002 by the absence of lappets in the female tail; and from L. oxymycteri Notarnicola, Bain & Navone, 2000 by absence of pre-cloacal papillae. L. legerae from O. quaestor and L. sigmodontis from Sigmodon hispidus in North America are closely related species, as indicated by Brant & Gardner's phylogenetic tree based on morphological characters. However, a new analysis is needed to include the recently described Argentinean species for a better understanding of the diversification of this genus. PMID:19424788

Notarnicola, Juliana; Navone, Graciela T

2009-06-01

51

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

PubMed Central

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 features of a Syncytin: it is specifically expressed in the placenta of the woodchuck Marmota monax, at the level of cells fusing into a syncytium; it can trigger cell-cell and virus-cell fusion ex vivo; and it has been conserved for >25 million years of evolution, suggesting an essential role in its host physiology. Remarkably, syncytin-Mar1 is unrelated to all other Syncytin genes identified thus far in mammals (primates, muroids, carnivores, and ruminants). These results extend the range of retroviral envelope gene “domestication” in mammals and show that these events occurred independently, on multiple occasions during evolution to improve placental development in a process of convergent evolution. PMID:24789792

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

2014-01-01

52

The largest fossil rodent  

PubMed Central

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

Rinderknecht, Andrés; Blanco, R. Ernesto

2008-01-01

53

Glis glis (Rodentia: Gliridae) BORIS KRYSTUFEK  

E-print Network

and Croatia. DOI: 10.1644/865.1. Key words: beech mast, edible dormouse, fat dormouse, glirid, hibernation Linnaeus, 1766:87. Type locality ``Habitat in Europa australi,'' restricted to Southern Carniola (5 southern Slovenia), by Violani and Zava (1995:111). Sciurus persicus Erxleben, 1777:417. Type locality

Hayssen, Virginia

54

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

ERIC Educational Resources Information Center

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…

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

2011-01-01

55

Transcriptome sequencing and phylogenomic resolution within Spalacidae (Rodentia)  

PubMed Central

Background Subterranean mammals have been of great interest for evolutionary biologists because of their highly specialized traits for the life underground. Owing to the convergence of morphological traits and the incongruence of molecular evidence, the phylogenetic relationships among three subfamilies Myospalacinae (zokors), Spalacinae (blind mole rats) and Rhizomyinae (bamboo rats) within the family Spalacidae remain unresolved. Here, we performed de novo transcriptome sequencing of four RNA-seq libraries prepared from brain and liver tissues of a plateau zokor (Eospalax baileyi) and a hoary bamboo rat (Rhizomys pruinosus), and analyzed the transcriptome sequences alongside a published transcriptome of the Middle East blind mole rat (Spalax galili). We characterize the transcriptome assemblies of the two spalacids, and recover the phylogeny of the three subfamilies using a phylogenomic approach. Results Approximately 50.3 million clean reads from the zokor and 140.8 million clean reads from the bamboo ratwere generated by Illumina paired-end RNA-seq technology. All clean reads were assembled into 138,872 (the zokor) and 157,167 (the bamboo rat) unigenes, which were annotated by the public databases: the Swiss-prot, Trembl, NCBI non-redundant protein (NR), NCBI nucleotide sequence (NT), Gene Ontology (GO), Cluster of Orthologous Groups (COG), and Kyoto Encyclopedia of Genes and Genomes (KEGG). A total of 5,116 nuclear orthologous genes were identified in the three spalacids and mouse, which was used as an outgroup. Phylogenetic analysis revealed a sister group relationship between the zokor and the bamboo rat, which is supported by the majority of gene trees inferred from individual orthologous genes, suggesting subfamily Myospalacinae is more closely related to subfamily Rhizomyinae. The same topology was recovered from concatenated sequences of 5,116 nuclear genes, fourfold degenerate sites of the 5,116 nuclear genes and concatenated sequences of 13 protein coding mitochondrial genes. Conclusions This is the first report of transcriptome sequencing in zokors and bamboo rats, representing a valuable resource for future studies of comparative genomics in subterranean mammals. Phylogenomic analysis provides a conclusive resolution of interrelationships of the three subfamilies within the family Spalacidae, and highlights the power of phylogenomic approach to dissect the evolutionary history of rapid radiations in the tree of life. PMID:24438217

2014-01-01

56

Capybara ( Hydrochaeris hydrochaeris rodentia: Hydrochaeridae): A mammalian seagrass herbivore  

Microsoft Academic Search

This note reports an unknown trophic interaction between a mammalian herbivore, the capybara (Hydrochaeris hydrochaeris), and the seagrassRuppia maritima (wigeongrass) and compares the feeding behavior of capybaras to other seagrass grazers. Observations were made in Spring\\u000a 2002 in the Barra Grande, a small, shallow, moderately stratified, bar-built estuary at Ilha Grande, Rio de Janeiro State,\\u000a southeast Brazil. The activities of

Joel C. Creed

2004-01-01

57

Population Genetics of Kangaroo Mice, Microdipodops (Rodentia: Heteromyidae)  

E-print Network

extant genera (Chaetodipus, Perognathus, Dipodomys, Heteromys, and Liomys) distributed from northwestern North America southward into northwestern South America. Heteromyidae is a relatively ancient lineage, originating between 22 and 35 million years...), and floristic transitions (Reveal 1979). Many of these alterations can be attributed to the glacial-interglacial cycles of the Pleistocene (Riddle 1995); recent human induced habitat destruction, however, also has plagued the area (Hafner & Upham 2011; Hafner...

Andersen, John

2012-07-16

58

FIRST PLEISTOCENE JUMPING MOUSE (ZAPUS, ZAPODINAE, RODENTIA) FROM UTAH  

Microsoft Academic Search

Two of the Little Dell Dam fossil localities produced the 1st Pleistocene records of the jumping mouse Zapus from Utah. We describe these teeth in detail and compare their morphology with both extinct and extant jumping mouse taxa. Although it is not possible to confidently assign these specimens to a particular species, the Little Dell Dam fossils are clearly distinct

Dennis R. Ruez; Christopher J. Bell

59

A comprehensive phylogeny of the gundis (Ctenodactylinae, Ctenodactylidae, Rodentia)  

Microsoft Academic Search

The subfamily Ctenodactylinae is known from the Early Miocene to the present. Today this group comprises five species, restricted to north and east equatorial areas in Africa. However, in Miocene times the ctenodactylines experienced their greatest diversification and widest distribution, from Asia, their land of origin, to Africa, which they entered during the Middle Miocene at the latest. So far

Raquel López-Antoñanzas; Fabien Knoll

2011-01-01

60

Molecular phylogenies of the genus Marmota (Rodentia Sciuridae): comparative analysis  

Microsoft Academic Search

Phylogenetic reconstructions of the genus Marmota were compared using data based on mitochondrial genes cit b (Kruckenhauser et al. 1999, Steppan et al. 1999, Herron et al. 2004), NADH-dehydrogenase subunit 4 (Kruckenhauser et al. 1999) and D-loop sequences and inter-SINEs nuclear DNA pattern (our data) as molecular markers. These studies present the evidence of a recent origin and North American

O. V. Brandler; E. A. Lyapunova

2009-01-01

61

Dietary ecology of Murinae (Muridae, Rodentia): a geometric morphometric approach.  

PubMed

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

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

2013-01-01

62

Complete mitochondrial genome of the Tamiops swinhoei (Rodentia: Sciuridae).  

PubMed

Abstract The complete mitochondrial genome of Tamiops swinhoei has been determined in this study. It is 16,513?bp in size and consists of 2 rRNA genes, 13 protein-coding genes, 22 tRNA genes and one non-coding region (D-loop). The overall base composition of the heavy strand of the T. swinhoei mitochondrial genome is A: 32.63%, T: 28.67%, C: 26.33% and G: 12.37%. The alignment of the Tamiops species control regions exhibited high genetic variability and rich A?+?T content (63.42%). PMID:25427814

Xu, Peng; Li, Yankuo; Guo, Yingrong; Cheng, Songlin; Lei, Ping

2014-11-27

63

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

PubMed

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. PMID:25102647

Villalobos, Federico; Gutierrez-Espeleta, Gustavo

2014-06-01

64

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

NASA Astrophysics Data System (ADS)

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).

Bogi?evi?, Katarina; Nenadi?, Draženko; Mihailovi?, Dušan

2012-02-01

65

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

PubMed Central

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

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

2013-01-01

66

Evolution of the genome size in Akodon (Rodentia, Cricetidae).  

PubMed

Nuclear DNA contents were estimated by microdensitometry in five species of Akodon rodents: Arodon molinae, A. dolores, A. mollis, A. azarae, Bolomys obscurus) and in three chromosomal varieties of A. molinae (2n = 42; 2n = 43, 2n = 22). The data obtained showed that the species with the highest DNA content was B. obscurus, followed in order of decreasing genome size by A. molinae, A. mollis, A. dolores and A. azarae. In A. molinae the forms with 2n = 42 chromosomes had the lowest and the forms with 2n = 44 the highest amount of DNA, while the forms with 2n = 43 had intermediate DNA contents. The variation in DNA amount detected in A. molinae was interpreted as a phenomenon of amplification occurring in the chromosomal areas involved in the chromosomal rearrangement giving rise to the polymorphism exhibited by this species. The DNA contents of shared chromosomes (chromosomes with similar size, morphology and G banding pattern, which are found in two or more phylogenetically related species), were compared and correlated with values of total nuclear DNA. The information obtained indicates that: (a) shared chromosomes have variable amounts of DNA: (b) in a given species there is a correlation between the amount of nuclear and chromosomal DNA in most shared chromosomes (and perhaps in most of the chromosomal complement), e.g., the higher the amount of nuclear DNA, the higher the content of DNA in shared chromosomes; (c) some chromosomes may undergo processes of amplification or deletion restricted to certain regions and usually related with mechanisms of chromosomal rearrangements.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:6358520

Bianchi, N O; Redi, C; Garagna, C; Capanna, E; Manfredi-Romanini, M G

1983-01-01

67

Chromosomal polymorphism of mandarin vole, Microtus mandarinus (Rodentia).  

PubMed

The mitotic and meiotic chromosomes of mandarin vole, Microtus mandarinus Milne-Edwards, from Shandong Province of China were analyzed by conventional, G- and C-banding and Silver-staining techniques. We detected chromosomal polymorphism in the vole, exhibiting diploid chromosome numbers 2n = 48-50 and variable morphology of the 1st pair, one medium sized telocentric pair and the X chromosomes. Four types of karyotypes were revealed in the population. According to banding analysis, there were pericentric inversion, Robertsonian fusion and translocation in M. mandarinus karyotype evolution. The X displayed two different morphologies, which could be explained by prericentric inversion and a telocentric autosome translocation. PMID:12830984

Wang, J X; Zhao, X F; Deng, Y; Qi, H Y; Wang, Z J

2003-01-01

68

Robertsonian polymorphism in chromosomes of Oryzomys subflavus (Rodentia, Cricetidae).  

PubMed

Eighty-four specimens of Oryzomys subflavus, collected in the State of Pernambuco, Brazil, were studied. A Robertsonian chromosome polymorphism, characterized by a varying diploid number of 50, 49, 48, and 46, was found. All specimens showed a chromosome arm number of 56. G-banding patterns in somatic cells allowed identification of the chromosome pairs (2, 3, 5, and 7) involved in centric fusion. C-banding revealed the presence of constitutive heterochromatin near the centromere the X chromosome and those of the autosomes. The Y chromosome presented a large heterochromatic block in the distal portion of its long arm. PMID:7030650

Maia, V; Hulak, A

1981-01-01

69

Consumption and mortality of the white-footed mouse (Rodentia: Muridae) and Ord's kangaroo rat (Rodentia: Heteromyidae) when fed carbaryl-bran grasshopper (Orthoptera) bait.  

PubMed

Two species of wild rodents (Ord's kangaroo rat, Dipodomys ordii Woodhouse, and the white-footed mouse, Peromyscus leucopus Rafinesque) were fed 0, 2, and 20% (AI) by weight concentrations of carbaryl-bran grasshopper bait in the laboratory to determine whether the bait would be consumed, the total quantity of bait consumed within a specified period, whether mortality would occur, and whether bait would be consumed if other foods were readily available. Consumption tests showed that bait ingestion was inversely proportional to concentration. No mortalities occurred at the 0% level, whereas the 2 and 20% concentration treatments resulted in 18.8 and 97.0% mortality, respectively. The apparent repellency of 20% bait indicated that starvation may have caused the deaths. Food preference tests disclosed that D. ordii and P. leucopus preferred natural forage rather than treated and untreated wheat bran in the laboratory. PMID:2126269

Krupovage, J R; Huddleston, E W; Valdez, R

1990-12-01

70

Phylogeography of a post-glacial colonizer: Microtus longicaudus (Rodentia: muridae).  

PubMed

The molecular phylogeography of Microtus longicaudus was investigated with DNA sequences of the mitochondrial cytochrome b gene. We used phylogenetic and pairwise distance methods to reconstruct the history of the species with particular emphasis on the Pacific Northwest. Genetic variation across the species was consistent with vicariant events during the Pleistocene and subsequent northern postglacial expansion following the receding Laurentide and Cordilleran ice sheets. The largest break (> 6% uncorrected sequence divergence) was found to exist between populations found southeast of the Colorado River (eastern Arizona, Colorado, Wyoming and New Mexico) and all other western populations. Other well-supported subclades were composed of samples from: (i) the islands and north coast of southeast Alaska; (ii) eastern Alaska, British Columbia, Washington and Oregon; and (iii) northern California, Idaho and Montana. Within subclades, divergence was low. Our results suggest that the close relationships among haplotypes within northern subclades are a result of recent colonization, whereas higher among-subclade divergence is caused by genetic differentiation during prolonged periods of isolation, possibly as a result of mid-Pleistocene climatic events. PMID:10672160

Conroy, C J; Cook, J A

2000-02-01

71

Phylogeography of a post-glacial colonizer: Microtus longicaudus (Rodentia: Muridae)  

Microsoft Academic Search

The molecular phylogeography of Microtus longicaudus was investigated with DNA sequences of the mitochondrial cytochrome b gene. We used phylogenetic and pairwise distance methods to reconstruct the history of the species with particular emphasis on the Pacific Northwest. Genetic variation across the species was consistent with vicariant events during the Pleistocene and subsequent northern postglacial expansion following the reced- ing

C. J. Conroy; J. A. Cook

2000-01-01

72

Retinal photoreceptors of two subterranean tuco-tuco species (Rodentia, Ctenomys): morphology, topography, and spectral sensitivity.  

PubMed

Traditionally, vision was thought to be useless for animals living in dark underground habitats, but recent studies in a range of subterranean rodent species have shown a large diversity of eye features, from small subcutaneous eyes to normal-sized functional eyes. We analyzed the retinal photoreceptors in the subterranean hystricomorph rodents Ctenomys talarum and Ctenomys magellanicus to elucidate whether adaptation was to their near-lightless burrows or rather to their occasional diurnal surface activity. Both species had normally developed eyes. Overall photoreceptor densities were comparatively low (95,000-150,000/mm(2) in C. magellanicus, 110,000-200,000/mm(2) in C. talarum), and cone proportions were rather high (10-31% and 14-31%, respectively). The majority of cones expressed the middle-to-longwave-sensitive (L) opsin, and a 6-16% minority expressed the shortwave-sensitive (S) opsin. In both species the densities of L and S cones were higher in ventral than in dorsal retina. In both species the tuning-relevant amino acids of the S opsin indicate sensitivity in the near UV rather than the blue/violet range. Photopic spectral electroretinograms were recorded. Unexpectedly, their sensitivity profiles were best fitted by the linear summation of three visual pigment templates with lambda(max) at 370 nm (S pigment, UV), at 510 nm (L pigment), and at 450 nm (an as-yet unexplained mechanism). Avoiding predators and selecting food during the brief aboveground excursions may have exerted pressure to retain robust cone-based vision in Ctenomys. UV tuning of the S cone pigment is shared with a number of other hystricomorphs. PMID:20737597

Schleich, Cristian E; Vielma, Alex; Glösmann, Martin; Palacios, Adrian G; Peichl, Leo

2010-10-01

73

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

PubMed Central

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

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

2012-01-01

74

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

PubMed Central

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

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

75

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

PubMed

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. PMID:23679835

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

2013-10-01

76

Western gray squirrel (Rodentia: Sciuridae): a primary reservoir host of Borrelia burgdorferi in Californian oak woodlands?  

PubMed

In California, dense woodlands have been recognized as important biotopes where humans are exposed to the nymphal stage of the western blacklegged tick, Ixodes pacificus Cooley & Kohls, the primary vector of the Lyme disease spirochete Borrelia burgdorferi sensu stricto (s.s.), in the far-western United States. To identify the principal reservoir host(s) of this spirochete, and of closely related spirochetes in the B. burgdorferi sensu lato (s.l.) complex, in dense woodlands in Mendocino County, California, approximately 50 species of birds and mammals, including wood rats and kangaroo rats, were evaluated as potential hosts for vector ticks and borreliae in 2002 and 2003. Although polymerase chain reaction (PCR) and sequencing analyses revealed that many vertebrate species had been exposed to one or more members of the B. burgdorferi s.l. spirochetal complex, only the western gray squirrel, Sciurus griseus, fulfilled the major criteria for a reservoir host of B. burgdorferi s.s. Ear-punch biopsies from eight of 10 squirrels collected from five separate woodlands were PCR-positive for B. burgdorferi s.s., 47% of I. pacificus larvae (n = 64) and 31% of nymphs (n = 49) removed from squirrels contained B. burgdorferi s.l., and the engorgement status of I. pacificus larvae was associated positively with acquisition of spirochetes. Overall, 83 and 100% of the amplicons sequenced from PCR-positive I. pacificus larvae and nymphs, respectively, were identified as B. burgdorferi s.s, Among the five remaining positive I. pacificus larvae, three contained B. bissettii and two had uncharacterized B. burgdorferi s.l. Borrelia burgdorferi s.s. was detected in one of five larvae and zero of two nymphs of the Pacific Coast tick, Dermacentor occidentalis Marx, that likewise had been removed from squirrels. The rickettsial agent of human anaplasmosis, Anaplasma phagocytophilum, was detected in the blood or ear biopsies of two squirrels and in one (1.6%) of 64 I. pacificus larvae and two (4.1%) of 49 nymphs obtained from squirrels. The one rickettsial-positive larva was coinfected with B. burgdorferi s.s. The apparently high reservoir potential of S. griseus for B. burgdorferi s.s., plus the fact that the geographic distribution of this squirrel coincides well with that of most reported human cases of Lyme disease in this region, indicated that it may be essential for maintaining foci of B. burgdorferi s.s. in certain types of woodlands. The findings with respect to A. phagocytophilum, although of less certain significance, suggest that S. griseus could serve as a secondary host of this rickettsia. PMID:15962792

Lane, Robert S; Mun, Jeomhee; Eisen, Rebecca J; Eisen, Lars

2005-05-01

77

ReEvaluation of Sinocastor (Rodentia: Castoridae) with Implications on the Origin of Modern Beavers  

Microsoft Academic Search

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

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

2010-01-01

78

Cytochrome b-based phylogeny of the Praomys group (Rodentia, Murinae): a new African radiation?  

Microsoft Academic Search

Complete cytochrome b gene sequences allows, for the first time, establishing a nearly complete phylogeny among the Praomys group sensu lato. The genera Praomys, Mastomys and Stenocephalemys appear paraphyletic. Myomys is polyphyletic and this genus name probably needs to be restricted to its type species, M. verreauxii. The genera Zelotomys and Colomys appear as sister groups. Mastomys pernanus and Malacomys verschureni nest

Émilie Lecompte; Laurent Granjon; Julian Kerbis Peterhans; Christiane Denys

2002-01-01

79

Cytochrome b-based phylogeny of the Praomys group (Rodentia, Murinae): a new African radiation?  

PubMed

Complete cytochrome b gene sequences allows, for the first time, establishing a nearly complete phylogeny among the Praomys group sensu lato. The genera Praomys, Mastomys and Stenocephalemys appear paraphyletic. Myomys is polyphyletic and this genus name probably needs to be restricted to its type species, M. verreauxii. The genera Zelotomys and Colomys appear as sister groups. Mastomys pernanus and Malacomys verschureni nest within the Praomys group, but their generic assignation must be further clarified. The genus Heimyscus appears closest to Praomys than to Hylomyscus. The different lineages probably result from an adaptive radiation at the end of the Miocene. PMID:12360851

Lecompte, Emilie; Granjon, Laurent; Peterhans, Julian Kerbis; Denys, Christiane

2002-07-01

80

INTER AND INTRASPECIFIC RELATIONSHIPS IN AKODON AZARAE AND CALOMYS LAUCHA (RODENTIA, SIGMODONTINAE) IN PAMPEAN AGROECOSYSTEMS  

Microsoft Academic Search

We studied social relationships in Akodon azarae and Calomys laucha (Roden- tia, Sigmodontinae), species that inhabit agroecosystems of Central Argentina. They show spatial segregation under field conditions, being C. laucha more abundant in the cropfields and A. azarae in their weedy margins (borders). In order to assess whether this spatial segregation was related to behavioral patterns, we conducted experimental encounters

Paula Courtalon; Alberto Dolcemascolo; Verónica Troiano; Martín R. Álvarez; María Busch

2003-01-01

81

Rattus norvegicus (Rodentia: Muridae) Infected by Leishmania (Leishmania) infantum (syn. Le. chagasi) in Brazil  

PubMed Central

In the present study we surveyed the fauna of phlebotomine sand flies and small mammals in peridomestic areas from a Brazilian municipality where the American cutaneous leishmaniasis (ACL) is endemic. A total of 608 female phlebotomine sand flies were captured during nine months in 2009 and 2010. Seven different species were represented with 60% of them being Lutzomyia intermedia and Lu. whitmani, both incriminated vectors of ACL. Lu. longipalpis, a proven vector of visceral leishmaniasis (VL) was also captured at high proportion (12.8%). Genomic DNA analysis of 136 species-specific pools of female sand flies followed by molecular genotyping showed the presence of Leishmania infantum DNA in two pools of Lu. longipalpis. The same Leishmania species was found in one blood sample from Rattus norvegicus among 119 blood and tissue samples analysed. This is the first report of Le. infantum in R. norvegicus in the Americas and suggests a possible role for this rodent species in the zoonotic cycle of VL. Our study coincided with the reemergence of VL in Governador Valadares. PMID:24707492

Lara-Silva, Fabiana de Oliveira; Michalsky, Érika Monteiro; Ferreira, Eduardo de Castro; Lopes, Maria Olímpia Garcia; Pinheiro, Aimara da Costa; Fortes-Dias, Consuelo Latorre; Dias, Edelberto Santos

2014-01-01

82

DNA Profiling of B Chromosomes from the Yellow-necked Mouse Apodemus flavicollis (Rodentia, Mammalia)  

PubMed Central

Using AP-PCR-based DNA profiling we examined some structural features of B chromosomes from yellow-necked mice Apodemus flavicollis. Mice harboring one, two, or three or lacking B chromosomes were examined. Chromosomal structure was scanned for variant bands by using a series of arbitrary primers and from these, informative bands were selected. The selection criteria used were the ability to differentiate between individuals of the species, to detect markers common for both A and B chromosomes, and, importantly, to differentiate between A- and B-chromosome sets. In addition to primers, profiling conditions were found to be critical for meeting the selection criteria. Primers and analysis conditions that demonstrated structural characteristics unique to the B-chromosome set are described. These characteristics included variant bands as qualitative parameters and altered electrophoretic band intensities as quantitative distinctions estimated by integration of densitometric profiles of electrophoretograms. B chromosome-specific molecular markers are easy to detect by AP-PCR-based DNA profiling in the presence of a full set of A chromosomes. Models for the origin of yellow-necked mouse B chromosomes are discussed in the context of presented data. PMID:10645950

Tani?, Nikola; Dedovi?, Nasta; Vujos?evi?, Mladen; Dimitrijevi?, Bogomir

2000-01-01

83

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

NASA Astrophysics Data System (ADS)

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.

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

2002-11-01

84

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

PubMed

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. PMID:24594062

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

2014-07-01

85

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

Microsoft Academic Search

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

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

2002-01-01

86

Late Cenozoic History of the Genus Micromys (Mammalia, Rodentia) in Central Europe  

PubMed Central

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. PMID:23671605

Horá?ek, Ivan; Knitlová, Markéta; Wagner, Jan; Kordos, László; Nadachowski, Adam

2013-01-01

87

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

PubMed Central

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

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

2013-01-01

88

Chromosomal speciation in a Rassenkreis of Venezuelan spiny rats (genus Proechimys, Rodentia, Echimyidae)  

Microsoft Academic Search

A series of populations of spiny rats (Proechimys) of NW and N Central Venezuela were found to belong to a circle of species and subspecies which surrounds the Andes of M6rida-CordiUera de la Costa mountain axis. This 'Rassenkreis' consists of 6 successive karyomorphs which exhibit a stepped-dine distribution (2n = 42, 44, 46, 48, 50 and 62). Each of the

Osvaldo A. Reig; Marisol Aguilera; María Alicia Barros; Myriam Useche

1984-01-01

89

Ontogeny and diversity of the oldest capybaras (Rodentia: Hydrochoeridae; late Miocene of Argentina)  

Microsoft Academic Search

According to our previous model for interpreting the fossil record of capybaras the cheek teeth grow in width and length throughout life; flexids (especially h.s.i. and h.t.i.) deepen allometrically resulting in diverse occlusal morphologies during ontogeny; in the more derived species the ‘onset’ of flexid development is pre-displaced, and the relative depth and development rate of the flexids increase. Consequently,

Cecilia M. Deschamps; Itatí Olivares; Emma Carolina Vieytes; María Guiomar Vucetich

2007-01-01

90

Mus spretus (Rodentia: Muridae) L. JAVIER PALOMO, ENRIQUE R. JUSTO, AND J. MARIO VARGAS  

E-print Network

:230) determined that this is a synonym of Mus musculus Linnaeus, 1758. Mus spicilegus lynesi Cabrera, 1923, 1923:431. Type locality ``alrededores de Melilla, Rif oriental,'' Morocco. Mus musculus spretus: Mus musculus. They recognized 15 subspecies, including M. m. spretus, and proposed the evolutionary

Hayssen, Virginia

91

Accelerated molecular evolution in Microtus (Rodentia) as assessed via complete mitochondrial genome sequences  

Microsoft Academic Search

Microtus is one of the most taxonomically diverse mammalian genera, including over 60 extant species. These rodents have evolved rapidly,\\u000a as the genus originated less than 2 million years ago. If these numbers are taken at face value, then an average of 30 microtine\\u000a speciation events have occurred every million years. One explanation for the rapid rate of cladogenesis in Microtus

Deborah A. Triant; J. Andrew DeWoody

2006-01-01

92

Cytogenetic nomenclature of deer mice, Peromyscus (Rodentia): revision and review of the standardized karyotype  

Microsoft Academic Search

A revision of the standardized karyotype of deer mice (Peromyscus) is presented. This revision addresses shortcomings of the original standardization, contains a substantial increase in the number of G-band markers and provides a nomenclature for the G-bands of each autosome and the X chromosome. Using the revised standardized karyotype, we specify the particular G-bands or patterns that identify each chromosome

I. F. Greenbaum; S. J. Gunn; S. A. Smith; B. F. McAllister; D. W. Hale; R. J. Baker; M. D. Engstrom; M. J. Hamilton; W. S. Modi; L. W. Robbins; D. S. Rogers; O. G. Ward; W. D. Dawson; F. F. B. Elder; M. R. Lee; S. Pathak

1994-01-01

93

Chromosomes and some issues of the evolution of the ground squirrel genus Citellus (Rodentia: Sciuridae)  

Microsoft Academic Search

?????? Citellus (s. str.) relictus, C. dauricus C. pygmaeus ???????? ??????????? ??????????? (2?=36, NF=72). ?????? ?. (Colobotis) erythrogenys ? ?. fulvus ?????????? ?? ???? ????? ???? ??????????????? ?????????? ? ????? ?-?????????. ???????? ?. (Urocitellus) undulatus (2n=32, NF=64) ??????????? ?????????? ?? ???? ????????? ???? ????? ?? ????????? ????????? ?. columbianus. ??????????? ??????? ??????????????? ???????????? ??????????? ??????????? ????????? Citellus, ????????????????? ??????????????? ????????????????,

E. A. Liapunova; N. N. Vorontsov

1970-01-01

94

Skeletal morphology and locomotor behavior of Pseudotomus eugenei (Rodentia, Paramyinae) from the Uinta Formation, Utah  

Microsoft Academic Search

A new skeleton of Pseudotomus eugenei is described and compared to extant large bodied rodents and those fossil manitshines represented by postcranial material (Pseudotomus robustus, Pseudotomus petersoni, and Man-itsha tanka). The postcranial skeleton of P. eugenei is unspecialized in terms of individual joint function as well as in overall proportions. The forelimb is heavily muscled with a generalized shoulder but

Rachel H. Dunn; D. Tab Rasmussen

2007-01-01

95

A new karyotype for the spiny rat Clyomys laticeps (Thomas, 1909) (Rodentia, Echimyidae) from Central Brazil  

PubMed Central

Abstract Clyomys Thomas, 1916 is a semifossorial rodent genus of spiny rats represented by only one species, Clyomys laticeps, which inhabits the tropical savannas and grasslands of central Brazil and eastern Paraguay. Here we describe a new karyotype of Clyomys laticeps found in populations of Emas National Park, Goiás state, Brazil. The four analyzed specimens had a diploid number (2n) of 32 and a fundamental autosome number (FN) of 54. Cytogenetic data include conventional staining, CBG and GTG-banding. The karyotype presents 12 meta/submetacentric pairs (1 to 12) and 3 pairs of acrocentrics (13 to 15) with gradual decrease in size. The X chromosome is a medium submetacentric and the Y is a medium acrocentric. The semifossorial habits together with habitat specificity could have contributed to the karyological variations found on this genus. PMID:24260659

Bezerra, Alexandra M. R.; Pagnozzi, Juliana M.; Carmignotto, Ana Paula; Yonenaga-Yassuda, Yatiyo; Rodrigues, Flávio H. G.

2012-01-01

96

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

PubMed

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. PMID:25336681

Paço, Ana; Adega, Filomena; Meštrovi?, Nevenka; Plohl, Miroslav; Chaves, Raquel

2014-10-01

97

Comments on the Systematics and Classification of the Beavers (Rodentia, Castoridae)  

Microsoft Academic Search

The systematics of the beavers (Castoridae) are reviewed and definitions are presented for each subfamilial group. Four subfamilies are recognized: primitive Agnotocastorinae (divided into two tribes, Agnotocastorini and Anchitheriomyini); burrowing beavers, Palaeocastorinae; giant beavers, Castoroidinae (containing two tribes, Castoroidini and Trogontheriini); and the Castorinae. The agnotocastorines are viewed as the ancestral group for all later subfamilies. The Palaeocastorinae is viewed

William W. Korth

2001-01-01

98

Characterization of the complete mitochondrial genome of the Hainan giant flying squirrel Petaurista hainana (Rodentia: Sciuridae).  

PubMed

Abstract The complete mitochondrial genome of Petaurista hainana from Hainan Island of China is 16,502?bp in length. Similar to most other mammals, it contains 13 protein-coding genes, 2 rRNAs, 22 tRNAs and 2 non-coding regions. The overall base composition of the H-strand is 31.77% A, 26.31% C, 13.31% G and 28.61% T. The base composition clearly showed the A-T skew. The mitochondrial genome of P. hainana presented in this report will be useful for species designation, conservation and phylogenetic study in Sciuridae. PMID:24409919

Kong, Lingming; Wang, Yanlu; Cong, Haiyan; Wang, Wenquan; Li, Yuchun

2014-01-10

99

Complete mitochondrial genome of the black giant squirrel Ratufa bicolor (Rodentia: Sciuridae).  

PubMed

Abstract The complete mitochondrial genome of black giant squirrel (Ratufa bicolor) from Hainan Island was sequenced and characterized in detail. The 16,563?bp genome was composed of 13 protein-coding genes, 22 tRNAs, 2 rRNAs and 2 non-coding regions. The mitochondrial genome of R. bicolor presented in this report will be useful for species identification, conversation and clarifying the controversial taxonomic status of genus Ratufa. PMID:24397765

Kong, Lingming; Wang, Wenquan; Cong, Haiyan; Liu, Zexin; Li, Yuchun

2014-01-01

100

A new species of Eutrichophilus (Phthiraptera: Trichodectidae) from the Brazilian black dwarf porcupine (Rodentia: Erethizontidae)  

E-print Network

A new species of chewing louse, Eutrichophilus koopmani (Phthiraptera: Trichodectidae), is described and illustrated based on an adult male specimen taken off the Brazilian black dwarf porcupine, Coendou nycthemera (Olfers) ...

Timm, Robert M.; Price, Roger D.

2000-01-01

101

Spermophilus xanthoprymnus (Rodentia: Sciuridae) MUTLU KART GU R AND HAKAN GU R  

E-print Network

be used in preference to Citellus Oken, 1816, because Oken's names were inconsistently binomial, Spermophilus, is still valid for the Asia Minor ground squirrel. The generic name Spermophilus means seed, 1835), the Asia Minor ground squirrel, is a group-living, diurnal, obligately hibernating marmotine

Hayssen, Virginia

102

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

PubMed Central

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

Faulkes, Chris G.

2014-01-01

103

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

USGS Publications Warehouse

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.

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

1998-01-01

104

Reservoir competence of the meadow vole (Rodentia: Cricetidae) for the Lyme disease spirochete Borrelia burgdorferi.  

PubMed

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. PMID:9775612

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

1998-09-01

105

Chromosomal characterizations in a restricted population of Geomys bursarius (Rodentia: Geomyidae)  

E-print Network

. H USA. 57:1280-1285 (1967) ~ Comings, D. E. : Chromosomle banding and. chromosomal proteins. In R. Sparkes. D, Comings and. F. Fox, eds. : Molecular Human Cyto- genetics. pp. 65-74. (Academic Press, -New York/London 1977). Davis, B. L. ; Williams... by new techniques. Chromosoma 36:272-280 (1972). K"n , M. C. and wilson, A. G . 1 Evolution at two levels in humans and. chimnanzees. Science 188:107-116 (1975). Lett, S. A. : Fluorescent probes of chromosome structure and replication. Can. J, Genet...

Stallings, Raymond L

1978-01-01

106

A new species of Heteromyoxyuris (Nematoda: Oxyuridae), parasite of Perognathus flavus (Rodentia: Heteromyidae) from Mexico.  

PubMed

Heteromyoxyuris otomii n. sp., which inhabits the intestinal caecum of Perognathus flavus (Heteromyidae), in Zaragoza, Hidalgo, Mexico, is described. This new species differs from the 2 other congeneric species in the morphology and length of lateral alae in males. Heteromyoxyuris deserti has simple lateral alae located at both sides of the body, whereas in the new species, these structures are double at both sides; in contrast, lateral alae of Heteromyoxyuris longejector begin at the posterior half of the body, whereas they arise in the first third in the new species. Heteromyoxyuris longejector was found in 2 new host species, i.e., Perognathus amplus and Chaetodipus hispidus. This record represents the first record for the species in Mexico, increasing its geographic distribution. PMID:18576798

García-Prieto, Luis; Falcón-Ordaz, Jorge; Lira-Guerrero, Georgina; Mendoza-Garfias, Berenit

2008-08-01

107

A Molecular Genetic Study of Hybridization in Four Species of Ground Squirrels (Spermophilus: Rodentia, Sciuridae)  

Microsoft Academic Search

Four species of ground squirrel—yellow (Spermophilus fulvus), russet (S. major), small (S. pygmaeus), and spotted (S. suslicus)—occur in the Volga region. Between S. major and S. pigmaeus, S. major and S. fulvus, and S. major and S. suslicus, sporadic hybridization was reported. Using sequencing and restriction analysis, we have examined the mtDNA C region in 13 yellow, 60 russet, 61

O. A. Ermakov; V. L. Surin; S. V. Titov; A. F. Tagiev; A. V. Luk'yanenko; N. A. Formozov

2002-01-01

108

Late Cenozoic History of the Genus Micromys (Mammalia, Rodentia) in Central Europe  

E-print Network

, Charles University, Praha, Czech Republic, 2 Institute of Geology AS CR, v.v.i., Praha, Czech Republic, 3, Australia Received December 4, 2012; Accepted March 22, 2013; Published May 6, 2013 Copyright: Ã? 2013 Hora AVOZ30130516 and RVO67985831 of the Institute of Geology AS CR, v.v.i. (JW). The funders had no role

Horacek, Ivan

109

Nucleolus organizer regions and B-chromosomes of wood mice (mammalia, rodentia, Apodemus)  

SciTech Connect

Distribution of nucleolus organizer regions (NORs) in karyotypes was studied in 10 species of wood mice, including Apodemus flavicollis, A. sylvaticus, A. uralensis (=A. microps), A. fulvipectus (=A. falzfeini), A. ponticus, A. hyrcanicus, A. mystacinus, A. agrarius, A. peninsulae, and A. speciosus. Peculiarities of NOR location in karyotypes can be used in interspecific diagnostics of wood mice. Intraspecific polymorphism of A. sylvaticus, A. agrarius, and A. peninsulae in terms of the number of NORs and their localization in chromosomes can serve as evidence for karyological differentiation in certain populations of these species. The minimum number of active NORs in mice of the genus Apodemus is two to four. Two A. flavicollis wood mice with karyotypes containing one small acrocentric B-chromosome (2n = 49) were identified among animals captured in Estonia. In A. peninsulae, B-chromosomes were found among animals captured in the following regions: the vicinity of Kyzyl (one mouse with 17 microchromosomes, 2n = 65); the vicinity of Birakan (two mice with one metacentric chromosome each, 2n = 49); and in the Ussuri Nature Reserve (one mouse with five B-chromosomes, including three metacentric and two dotlike chromosomes; 2n = 53). In the latter animal, the presence of NORs on two metacentric B-chromosomes was revealed; this is the first case of identification of active NORs on extra chromosomes of mammals. 29 refs., 4 figs., 1 tab.

Boeskorov, G.G. [Yakutia Institute of Biology, Yakutsk (Russian Federation); Kartavtseva, I.V. [Biological Soil Institute, Vladivostok (Russian Federation); Zagorodnyuk, I.V. [Shmal`gausen Institute of Zoology, Kiev (Ukraine); Belyanin, A.N. [Saratov State Univ. (Russian Federation); Lyapunova, E.A. [Kol`tsov Institute of Developmental Biology, Moscow (Russian Federation)

1995-02-01

110

Glaciation effects on the phylogeographic structure of Oligoryzomys longicaudatus (Rodentia: Sigmodontinae) in the southern Andes.  

PubMed

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

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

2012-01-01

111

A new species of Geomydoecus (Mallophaga: Trichodectidae) from the Texas pocket gopher, Geomys personatus (Rodentia: Geomyidae)  

E-print Network

: As in Fig. 4. Head length 0.290-0.315 (3: 0.305 ? 0.0094); tem ple width 0.430-0.440 (3: 0.434 ? 0.0045); submarginal temple seta length 0.045-0.050 (2: 0.048 ? 0.0029); marginal temple seta length 0.045-0.050 (3: 0.049 ? 0.0026). Total length 1....0 ? 0.89). Subgenital plate with 19-22 (3: 20.3 ? 1.37) setae. Genital sac as in Fig. 3; length 0.165-0.195 (3: 0.180 ? 0.0138), width 0.200-0.215 (3: 0.210 ? 0.0062); with no complete loops or evidence of lines in medioanterior portion. male...

Timm, Robert M.; Price, Roger D.

1979-01-01

112

Phylogeny, evolution, and systematics of the Galea musteloides complex (Rodentia: Caviidae)  

E-print Network

) from the central Bolivian Andes, G. m. auceps (Thomas, 1911) from the Altiplano region around Lake Titicaca, and G. m. demissa (Thomas, 1921) from the Bolivian lowlands adjacent to the Andean foothills

113

Ondatra zibethicus (Arvicolinae, Rodentia) Dental Microwear Patterns as a Potential Tool for Palaeoenvironmental Reconstruction  

Microsoft Academic Search

Subfossil muskrat remains are numerous in the lower strata at the Lubbock Lake Landmark, Southern High Plains of Texas, dating from c.11,100bp to 8500bp. This period witnessed a significant change in palaeoclimate and habitat at Lubbock Lake and the Southern High Plains. These changes caused the disappearance of many plant and animal species, and the emergence of many others. The

Patrick J. Lewis; Maria Gutierrez; Eileen Johnson

2000-01-01

114

Notocotylus loeiensis n. sp. (Trematoda: Notocotylidae) from Rattus losea (Rodentia: Muridae) in Thailand  

PubMed Central

Notocotylus loeiensis n. sp. (Trematoda: Notocotylidae) is described from the cecum of the lesser rice field rat (Rattus losea), from Loei Province in Thailand with a prevalence of 9.1% (eight of 88 rats infected). The new species differs from previously described Notocotylus species mainly by the extreme prebifurcal position of the genital pore and the number of ventral papillae. This is the first description at the species level of Notocotylus from mammals in Southeast Asia. PMID:21395203

Chaisiri, K.; Morand, S.; Ribas, A.

2011-01-01

115

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

PubMed

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-?H2AX. 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. PMID:25227566

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

2014-01-01

116

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

PubMed

Abstract 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. PMID:24021005

He, Kai; Jiang, Xue-Long

2013-09-11

117

TWO NEW SPECIES OF HYMENOLEPIS (CESTODA: HYMENOLEPIDIDAE) FROM MURID RODENTS (RODENTIA: MURIDAE) IN THE PHILIPPINES  

E-print Network

) IN THE PHILIPPINES Arseny A. Makarikov, Vasyl V. Tkach*, and Sarah E. Bush Institute of Systematics and Ecology, Apomys microdon, and Rattus everetti collected on Luzon Island, Philippines. Hymenolepis bicauda n. sp Hymenolepis diminuta was the only member of the genus previously reported from the Philippines. The genus

Clayton, Dale H.

118

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

PubMed Central

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

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

119

Molecular Phylogeny of the Marmots (Rodentia: Sciuridae): Tests of Evolutionary and Biogeographic Hypotheses  

Microsoft Academic Search

There are 14 species of marmots distributed across the Holarctic, and despite extensive systematic study, their phylogenetic relationships remain largely unresolved. In particular, compre- hensive studies have been lacking. A well-supported phylogeny is needed to place the numerous ecological and behavioral studies on marmots in an evolutionary context. To address this situation, we obtained complete cytochrome (cyt) b sequences for

SCOTT J. STEPPAN; MIKHAIL R. AKHVERDYAN; ELENA A. LYAPUNOVA; DARRILYN G. FRASER; NIKOLAI N. VORONTSOV; ROBERT S. HOFFMANN; MICHAEL J. BRAUN

120

Molecular phylogeny of the marmots (Rodentia: Sciuridae): tests of evolutionary and biogeographic hypotheses.  

PubMed

There are 14 species of marmots distributed across the Holarctic, and despite extensive systematic study, their phylogenetic relationships remain largely unresolved. In particular, comprehensive studies have been lacking. A well-supported phylogeny is needed to place the numerous ecological and behavioral studies on marmots in an evolutionary context. To address this situation, we obtained complete cytochrome (cyt) b sequences for 13 of the species and a partial sequence for the 14th. We applied a statistical approach to both phylogeny estimation and hypothesis testing, using parsimony and maximum likelihood-based methods. We conducted statistical tests on a suite of previously proposed hypotheses of phylogenetic relationships and biogeographic histories. The cyt b data strongly support the monophyly of Marmota and a western montane clade in the Nearctic. Although some other scenarios cannot be rejected, the results are consistent with an initial diversification in North America, followed by an invasion and subsequent rapid diversification in the Palearctic. These analyses reject the two major competing hypotheses of M. broweri's phylogenetic relationships--namely, that it is the sister species to M. camtschatica of eastern Siberia, and that it is related closely to M. caligata of the Nearctic. The Alaskan distribution of M. broweri is best explained as a reinvasion from the Palearctic, but a Nearctic origin can not be rejected. Several other conventionally recognized species groups can also be rejected. Social evolution has been homoplastic, with large colonial systems evolving in two groups convergently. The cyt b data do not provide unambiguous resolution of several basal nodes in the Palearctic radiation, leaving some aspects of pelage and karyotypic evolution equivocal. PMID:12066297

Steppan, S J; Akhverdyan, M R; Lyapunova, E A; Fraser, D G; Vorontsov, N N; Hoffmann, R S; Braun, M J

1999-12-01

121

Multilocus Phylogenetics of a Rapid Radiation in the Genus Thomomys (Rodentia: Geomyidae)  

Microsoft Academic Search

Species complexes undergoing rapid radiation present a challenge in molecular systematics because of the possibility that ancestral polymorphism is retained in component gene trees. Coalescent theory has demonstrated that gene trees often fail to match lineage trees when taxon divergence times are less than the ancestral effective population sizes. Suggestions to increase the number of loci and the number of

NATALIA M. BELFIORE; Liang Liu; Craig Moritz

2008-01-01

122

Revision of the chewing louse genus Eutrichophilus (Phthiraptera: Trichodectidae) from the New World porcupines (Rodentia: Erethizontidae)  

E-print Network

Werneck (1945,1950)redescribedmostofthespecies,andEmersonandPrice(1975)reviewedthetypehostsanddistributionsandpro-vided illustrationsforthespeciesofEutrichophilusfoundinnorthernSouthAmerica...,asMorserecordeditasaporcupinefrom"Neb."[Nebras-ka].Curiously,anderroneously,KelloggandFer- ris(1915,p.59)reported,"Thisspecies[E.seto-sus]isapparentlycommontotheporcupinesofbothEuropeandAmerica."Therearenoporcu- pines,eithererethizontidsorhystrichids,endemictoEurope.Lyal(1985)erroneouslylistedtheyearofau-thorship for...

Timm, Robert M.; Price, Roger D.

1994-03-01

123

West Nile virus infection in tree squirrels (Rodentia: Sciuridae) in California, 2004-2005.  

PubMed

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 log(10) 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

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

2007-05-01

124

Evaluation of squirrels (Rodentia: Sciuridae) as ecologically significant hosts for Anaplasma phagocytophilum in California.  

PubMed

Granulocytic anaplasmosis (GA), caused by Anaplasma phagocytophilum, is a potentially fatal, emerging rickettsial disease of humans, domestic animals, and wildlife. The purpose of this study was to determine whether sciurids from multiple areas of northern California were infested with ticks or exposed to or infected with A. phagocytophilum using polymerase chain reaction (PCR) and indirect-fluorescent antibody (IFA) serology. Sciurids of nine different tree- and ground-dwelling species were assessed: arboreal squirrels (western and eastern gray squirrels, Sciurus griseus and S. carolinensis, and Douglas squirrels, Tamiasciurus douglasii) but not northern flying squirrels (Glaucomys sabrinus) had greater evidence of exposure and current infection than did semiarboreal or ground dwelling sciurids (California ground squirrels, Spermophilus beecheyi, and chipmunks, Tamias spp.). Western gray squirrels had the most extensive exposure (70.7% seroprevalence and 12.1% PCR prevalence). Positive squirrels were identified in all regions where squirrels were collected. A logistic regression identified being a western gray squirrel (OR = 20.5, P = 2.95 X 10(-8)) and from the north coastal region of California (OR = 9.052, P = 1.41 X 10(-6)) as having the highest risk of exposure to A. phagocytophilum. Five of nine sciurid species had evidence of infestation with Ixodes pacificus or I. spinipalpis that could vector A. phagocytophilum. Extensive exposure from multiple areas suggests sciurids may be important in the maintenance of GA in California and indicates that studies of reservoir competence of these species are warranted. PMID:18714881

Nieto, Nathan C; Foley, Janet E

2008-07-01

125

Complete mitochondrial genome of the Pallas's squirrel Callosciurus erythraeus (Rodentia: Sciuridae).  

PubMed

Abstract The complete mitochondrial genome of Pallas's squirrel (Callosciurus erythraeus) from Sichuan Province was sequenced and characterized in detail. It was 16,550?bp in length and composed of 13 protein-coding genes, 22 tRNAs, 2 rRNAs and 1 control region. The mitochondrial genome of C. erythraeus presented in this report will be useful for species identification, genetic variability and clarifying the controversial taxonomic status of genus Callosciurus. PMID:25319295

Hu, Lanlin; Peng, Rui; Zou, Fangdong

2014-10-16

126

Geometric morphometric study of the skull shape diversification in Sciuridae (Mammalia, Rodentia).  

PubMed

It is generally accepted that the high phenotypic diversity of mammals is a combined result of developmental constraint and ecological adaptation, although the influence of these endogenous and exogenous factors varies in different mammal groups. The rodent family Sciuridae represents an ideal candidate for examining phenotypic diversity in relation to phylogeny and ecological adaptations. In the present study, we investigate the effects of phylogeny and lifestyle on the skull shape in different species of Sciuridae by applying geometric morphometric methods. In addition, we investigate the importance of allometry on sciurid skull shape, because results from geometric morphometrics sometimes dispute those of traditional morphometry. Here, we identify significant associations between patristic distances obtained from molecular phylogeny and shape distances in all 3 views of the cranium and the lateral view of the mandible. Multivariate regression demonstrates that shape differences among lifestyle categories are substantial, especially in the dorsal and ventral structures after the influence of phylogeny is taken into account. Allometry plays an important role in the shape variation, although its importance on different skull structures varies. Our results indicate that complex structures of this highly diverse mammal group, which occupies different niches, are affected by ecological factors and developmental constraint. PMID:24952964

Lu, Xuefei; Ge, Deyan; Xia, Lin; Huang, Chengming; Yang, Qisen

2014-06-01

127

A new karyotype for the spiny rat Clyomys laticeps (Thomas, 1909) (Rodentia, Echimyidae) from Central Brazil.  

PubMed

Clyomys Thomas, 1916 is a semifossorial rodent genus of spiny rats represented by only one species, Clyomys laticeps, which inhabits the tropical savannas and grasslands of central Brazil and eastern Paraguay. Here we describe a new karyotype of Clyomys laticeps found in populations of Emas National Park, Goiás state, Brazil. The four analyzed specimens had a diploid number (2n) of 32 and a fundamental autosome number (FN) of 54. Cytogenetic data include conventional staining, CBG and GTG-banding. The karyotype presents 12 meta/submetacentric pairs (1 to 12) and 3 pairs of acrocentrics (13 to 15) with gradual decrease in size. The X chromosome is a medium submetacentric and the Y is a medium acrocentric. The semifossorial habits together with habitat specificity could have contributed to the karyological variations found on this genus. PMID:24260659

Bezerra, Alexandra M R; Pagnozzi, Juliana M; Carmignotto, Ana Paula; Yonenaga-Yassuda, Yatiyo; Rodrigues, Flávio H G

2012-01-01

128

A remarkable autosomal heteromorphism in Pseudoryzomys simplex 2n = 56; FN = 54–55 (Rodentia, Sigmodontinae)  

PubMed Central

Pseudoryzomys simplex, the false rice rat, is a monotypic genus of the Oryzomyini tribe (Sigmodontinae) distributed in part of Bolivia, Paraguay, Argentina and Brazil. Its diploid number has been described as 56 acrocentric chromosomes decreasing in size and no karyotype figure has been depicted. Herein, we present karyotypic data on P. simplex, including chromosome banding and molecular fluorescent in situ hybridization using telomeric sequences and the whole X-chromosome of its sister clade Holochilus brasiliensis (HBR) as probes. A case of remarkable autosomal heteromorphism due to the presence of a whole heterochromatic arm leading to the variability of FN is reported, as well as the occurrence of regions of homology between the X and Y chromosomes (pseudoautosomal regions) after chromosome painting with the HBR X probe on P. simplex metaphases. PMID:23885202

Moreira, Camila Nascimento; Di-Nizo, Camilla Bruno; de Jesus Silva, Maria José; Yonenaga-Yassuda, Yatiyo; Ventura, Karen

2013-01-01

129

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

PubMed

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. PMID:19209758

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

130

Urocitellus canus (Rodentia: Sciuridae) F. RUSSELL COLE AND DON E. WILSON  

E-print Network

commonly called Merriam's ground squirrel. A nondescript, thin- tailed, unmarked ground squirrel, it is 1, Nevada, and California. It prefers grasslands and pastures with big sagebrush and western juniper completed 25 March 2008 w w w . m a m m a l o g y . o r g Urocitellus canus (Merriam, 1898) Merriam's Ground

Hayssen, Virginia

131

Carrion consumption by Dasyprocta leporina (Rodentia: Dasyproctidae) and a review of meat use by agoutis.  

PubMed

The consumption of the carrion of a tapiti by a reintroduced female Dasyprocta leporina was observed in the wild. Herein, besides describing this event, we reviewed other evidence of vertebrate consumption by agoutis. Most of the studies describing this behaviour have been carried out in captivity. The preyed animals included birds and small rodents, which were sometimes killed by agoutis. This pattern suggests that this is not an anomalous behaviour for the genus, reflecting its omnivorous habits. This behaviour can be a physiologically sound feeding strategy, so new studies should focus on the temporal variation in the consumption of this resource, possibly related to food scarcity periods or to reproductive seasons, when the need for high-quality food tends to increase. PMID:25296206

Figueira, L; Zucaratto, R; Pires, A S; Cid, B; Fernandez, F A S

2014-08-01

132

Feeding biology of the dassie-rat Petromus typicus (Rodentia, Hystricognathi, Petromuridae) in captivity  

Microsoft Academic Search

We examined the feeding biology of the poorly known dassie-rat Petromus typicus. External morphol- ogy indicates that the digging for soil-inhabiting invertebrates as food is unlikely. Animals in captivity refuse to eat insect larvae and data from field studies indicate that invertebrates play no major role with regard to the intake quantity. Observations on jaw movements and occlusion patterns of

Andrea Mess; Manfred Ade

2005-01-01

133

Occurrence of Dermacentor variabilis (Acari: Ixodidae) around a porcupine (Rodentia: Erthethizontidae) carcass at Camp Ripley, Minnesota.  

PubMed

In May 2000, a dead porcupine (Erethizon dorsatum Culiver) was found on an infrequently traveled dirt road at Camp Ripley, MN. The presence of late instar Calliphoridae suggested that the porcupine died within the past 4 to 7 d. Adult carrion (Silphidae) and rove (Staphylinidae) beetles were observed under the carcass. In June, a large number of adult American dog ticks, Dermacentor variabilis (Say), were observed questing on the porcupine and the surrounding grass. Six zones were established around the carcass, and each zone was sampled for ticks once a month from June through September. Ticks were captured in June and July, and 93% were captured within 2 m of the carcass. Gases released as part of the decomposition process were believed to attract the ticks to the carcass. PMID:12597663

McNemee, Richard B; Sames, William J; Maloney, Francis A

2003-01-01

134

An anatomical study of the brains of Dipodomys (Mammalia: Rodentia: Heteromyidae).  

PubMed

Whole brains and Nissl-stained serial sections of 3 species of kangaroo rat (Dipodomys spectabilis, D. ordii, D. merriami) were compared for interspecific differences. Neuroanatomical variations were conservative in nature. Examination of the cerebellum revealed possible differences in locomotion and ecology. Dipodomys ordii exhibited more neurological evidence for increased specialization of the hindlimbs, while D. merriami had the least differentiated cerebellar surface, thereby suggesting more stereotyped movements of the hindlimbs. Dipodomys spectabilis had abilities that lie somewhere between those of D. ordii and D. merriami. Stereological analysis demonstrated little difference in the percent of total brain volume comprising the telencephalon, diencephalon, cerebellum, and brain stem; and it revealed the relative position of the cranial nerve nuclei. PMID:507367

Dressler, J B

1979-01-01

135

Tactile discriminatory ability and foraging strategies in Kangaroo rats and pocket mice (Rodentia: Heteromyidae)  

Microsoft Academic Search

A comparative study of seasonal food hoarding activity and tactile discriminatory ability in four species of heteromyid rodents (Dipodomys panamintinus, D. merriami, Perognathus longimembris, and P. formosus) was conducted in laboratory test arenas. Animals were tested individually to determine their treatment of seed (white millet) and seed mimics (glass beads and gravel) offered as food. In general, all animals showed

Debra K. Lawhon; Mark S. Hafner

1981-01-01

136

Karyotypic variation in the Andean rodent Phyllotis xanthopygus (Waterhouse, 1837) (Rodentia, Cricetidae, Sigmodontinae)  

PubMed Central

Abstract Phyllotis xanthopygus (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. PMID:25610549

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

2014-01-01

137

Comparative cytogenetics of spiny rats of the genus Proechimys (Rodentia, Echimyidae) from the Amazon region.  

PubMed

We made a comparative analysis of the cytogenetics of spiny rat species of the genus Proechimys collected from several sites of the Madeira River basin (Amazonas State, Brazil) and Jari River valley (Pará State, Brazil). Individuals were assigned to three groups based on diploid and fundamental numbers: 2n = 28, FN = 46 (P. cuvieri and P. gr. longicaudatus); 2n = 38, FN = 52 (Proechimys gr. guyannensis), and 2n = 40, FN = 54 (P. gardneri). The nucleolar organizer region (NOR) was interstitial on the long arm of one submetacentric pair, as seen in all species of Proechimys analyzed thus far. However, its position in the karyotype was variable. A duplication of the NOR in one of the homologues was detected in P. gr. longicaudatus from the Aripuanã basin along the mid Madeira. The C-band pattern varied between species and, together with the NOR, allowed the identification of two evolutionary units in P. gr. longicaudatus in the region of the mid Madeira River (cytotypes A and B). The morphology and banding of the sex chromosomes were species specific. A range extension is suggested for the geographic distribution of P. gardneri and P. gr. longicaudatus. Moreover, we suggest that species of Proechimys with 2n = 38 chromosomes are restricted to east of the Negro River and north of the Amazon River. We also revised the published chromosome data available for Proechimys. PMID:22576911

Eler, E S; da Silva, M N F; Silva, C E F; Feldberg, E

2012-01-01

138

A new species of Echimys Cuvier, 1809 (Rodentia, Echimyidae) from Brazil  

Microsoft Academic Search

Here we describe a new species of Echimyidae Amazonian rodent, Echimys vieirai sp. nov., based on two individuals from the south bank of Amazon river between the lower Madeira river to the right bank of the Tapajós, respectively in the Brazilian states of Amazonas and Pará, Brazil. The main diagnostic characteristic of this new species is the presence of a

Gilson Evaristo Iack-Ximenes; Mario de Vivo; Alexandre Reis Percequillo

2005-01-01

139

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

PubMed

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

Cox, Philip G; Faulkes, Chris G

2014-01-01

140

Cryptic Speciation and Chromosomal Repatterning in the South African Climbing Mice Dendromus (Rodentia, Nesomyidae)  

PubMed Central

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. PMID:24551165

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

2014-01-01

141

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

PubMed

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

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

2010-01-01

142

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

PubMed Central

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

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

2010-01-01

143

Chromosomes and systematics of some north American species of the genus Marmota (Rodentia: Sciuridae)  

Microsoft Academic Search

Zusammenfassung Die Zahl der diploiden Chromosomen vonMarmota caligata undM. flaviventris ist 42 in Bevölkerungen der nördlichen und südlichen Verbreitungsgebiete beider Spezies. Ein Vergleich zwischen den bisher veröffentlichten Informationen überMarmota-Chromosomen mit Angaben über ihre Morphologie, Ekologie, Zoogeographie legt nahe, dass die ursprüngliche Chromosomenzahl 2n 38–40 war.

R. S. Hoffmann; C. F. Nadler

1968-01-01

144

Evolution of marmots (Rodentia, Sciuridae): combining information on labial and lingual sides of the mandible  

Microsoft Academic Search

The morphology of the lingual side of the mandible was analysed in the genusMarmota. Adults from 12 of 14 living species were compared using geometric morphometric techniques. The information on the lingual\\u000a side was then combined with that of the labial side from a previous analysis. The combined dataset is the most complete description\\u000a of a marmot mandible ever used

Andrea Cardini

2004-01-01

145

Postnatal ontogeny of the mandible and ventral cranium in Marmota species (Rodentia, Sciuridae): allometry and phylogeny  

Microsoft Academic Search

Post-natal ontogenetic variation of the marmot mandible and ventral cranium is investigated in two species of the subgenus\\u000a Petromarmota (M. caligata, M. flaviventris) and four species of the subgenus Marmota (M. caudata, M. himalayana, M. marmota, M. monax). Relationships between size and shape are analysed using geometric morphometric techniques. Sexual dimorphism is negligible,\\u000a allometry explains the main changes in shape

Andrea Cardini; Paul O’Higgins

2005-01-01

146

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

PubMed

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. PMID:25781118

Dalapicolla, Jeronymo; Leite, Yuri L R

2015-01-01

147

Low, complex and probably reticulated chromosome evolution of Sciuromorpha (Rodentia) and Lagomorpha.  

PubMed

Lagomorpha (rabbits and pikas) and Sciuromorpha (squirrels) are grouped in the Glires superorder. Their chromosome diversification, since their separation from the eutherian mammalian common ancestor, was characterized by a low rate of chromosome rearrangements. Consequently, the structure of some chromosomes was either conserved or only slightly modified, making their comparison easy at the genus, family and even order level. Interspecific in situ hybridization (Zoo-FISH) largely corroborates classical cytogenetic data but provides much more reliability in comparisons, especially for distant species. We reconstructed common ancestral karyotypes for Glires, Lagomorpha, Sciuromorpha, and Sciuridae species, and then, determined the chromosome changes separating these ancestors from their common eutherian ancestor. We propose that reticulated evolution occurred during the diversification of Glires, which implies that several pericentric inversions and Robertsonian translocations were conserved in the heterozygous status for an extensive period. Finally, among Lagomorpha and Sciuromorpha, we focused on Leporidae and Sciuridae chromosome evolution. In the various attempts to establish dichotomic evolutionary schemes, it was necessary to admit that multiple homoplasies (convergent and reverse rearrangements) occurred in Sciuridae and in a lesser degree, in Leporidae. In Leporidae, additional rearrangements were sufficient to propose a resolved phylogeny. However, a resolved phylogeny was not possible for Sciuridae because most of the rearrangements occurred in terminal branches. We conclude that a reticulated evolution took place early during the evolution of both families and lasted longer in Sciuridae than in Leporidae. In Sciuridae, most chromosome rearrangements were pericentric inversions involving short fragments. Such rearrangements have only mild meiotic consequences, which may explain the long persistence of the heterozygous status characterizing reticulated evolution. PMID:22846378

Richard, F; Dutrillaux, B

2012-01-01

148

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

PubMed

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. PMID:24628052

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

149

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

PubMed

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. PMID:23671605

Horá?ek, Ivan; Knitlová, Markéta; Wagner, Jan; Kordos, László; Nadachowski, Adam

2013-01-01

150

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

PubMed Central

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.

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

2015-01-01

151

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

PubMed

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. PMID:24482421

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

2014-04-01

152

Landscape correlates of the distribution of coypu Myocastor coypus (Rodentia, Mammalia) in Argentinean Pampas  

Microsoft Academic Search

The coypu is a rodent indigenous to aquatic habitats in southern South America, which is considered a pest where it has been introduced and a valuable furbearer resource within its native range. The objective of this study was to identify the main landscape correlates of coypu distribution in the Pampas. Previous studies provided two non-exclusive hypotheses: (1) if hunting pressure

L. R. Leggieri; M. L. Guichón; M. H. Cassini

2011-01-01

153

C-banded karyotype of Myocastor coypus (Molina, 1782) from Turkey (Mammalia: Rodentia).  

PubMed

The present study reports the C-band patterns of chromosomes of Myocastor coypus from Turkey. The karyotype of M. coypus is comprised of (2n) 42 chromosomes, the number of chromosomal arms (FN) was 83 and the number of autosomal arms (FNa) was 80. The X chromosome was a medium-sized metacentric and the Y chromosome was acrocentric and the smallest in the set. Two metacentric chromosomes have secondary constrictions. Most autosomes in this species were centromeric C-positive and some autosomes had telomeric C-bands. The X chromosome has centromeric heterochromatin, while the Y chromosome appeared to be entirely heterochromatic. PMID:19459458

Iliker, Ay?egül; Arslan, Atilla; Pamuko?lu, Nahit; Albayrak, Irfan

2009-01-01

154

Observations on the fetal morphology in Myocastor coypus bonariensis (coypu) (Rodentia, Myocastoridae).  

PubMed

The goal of this work was to characterize the morphology of fetuses of Myocastor coypus bonariensis (coypu) after 60, 90, 120 and 135 days post-coitus (d.p.c.). At all the ages, gestational sacs showed an elliptical shape. Placentas were discoidal, with a unilobular external appearance in fetuses of 60 d.p.c. and with lobulations separated by a groove in fetuses of other ages. The umbilical cord, wrapped around the fetal body, showed a proximal dilatation in 60-d.p.c. fetuses, being its course uniform and a little spiral in the other ages. The 60-d.p.c. fetuses showed differentiation of corporal regions, prominent encephalic vesicles and little developed earlobes located in the laterals of the skull, in the limit with the cervical area and in straight line with the optical vesicles. The primitive forelimbs showed differentiation of arm, forearm and hand. In the hindlimbs, the inter-digital membrane was observed joining the fingers along all their length. Fetuses of 90 d.p.c. showed developed eyelids and closed palpebral cleft, developed auricular pavilions (earlobes), hairy follicles in the facial region (vibrissae) and in the skull and bent limbs. Fetuses of 120 and 135 d.p.c. showed a bodily cover constituted by a dense pilous covering, spread palpebral clefts, open mouth, bent limbs and inter-digital membranes in the hindlimbs. PMID:19032632

Felipe, A E; Masson, P G

2008-12-01

155

Distributional Survey of Rare Small Mammals (Orders Insectivora, Chiroptera, and Rodentia)  

E-print Network

thysanodes)............................................25 Yuma myotis (Myotis yumanensis included: Neotoma albigula brevicauda, Myotis californicus, M. thysanodes, M. yumanensis, and Antrozous California myotis (Myotis californicus) ......................................25 Fringed myotis (Myotis

156

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

PubMed

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

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

2015-04-01

157

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

PubMed

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. PMID:17008077

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

2007-01-01

158

High-resolution G-banding of chromosones in the common vole Microtus arvalis (Rodentia, Arvicolidae)  

PubMed

We have applied the G-banding technique to early metaphase chromosomes of the vole Microtus arvalis, form 'arvalis'. Fifty metaphase spreads were analysed from spleen and primary fibroblast cell cultures from six voles. We were able to distinguish 435 bands in the haploid set. An idiogram was constructed from the chromosomes at various stages of condensation. PMID:8931356

Mazurok, N A; Isaenko, A A; Nesterova, T B; Zakian, S M

1996-01-01

159

DNA of Akodon (Rodentia, Cricetidae). II. Molecular hybridization of repetitive DNA sequences.  

PubMed

Interspecies repetitive DNA homology was studied in akodont rodents related at generic and suprageneric levels. The homology was determined by taking the species Akodon molinae as the reference species. The 3H-DNA/DNA hybridization on filters showed a closer relationship between A. molinae and A. azarae, A. dolores and A. mollis than between A. molinae and Bolomys obscurus. These data agree with the taxonomical ranking of the species. The quantity and quality of the hybrid DNAs were measured by investigating their thermal stabilities and subsequent comparison to the results obtained on the reference species. These data indicate high similitude between the repetitive DNA of A. dolores and A. molinae. Increasing differences were shown to occur in the repetitive DNA of A. mollis, B. obscurus and A. azarae, respectively. Since these results coincide with the G-banding homologies and differ slightly from the taxonomical rank, it is speculated that the divergency between the DNA of A. molinae and A. azarae is the result of a differential process of DNA amplification which is not related to the phylogenetical distance separating the two species. PMID:6762920

Vidal-Rioja, L; Bianchi, N O; Catala, A; Semorile, L

1982-01-01

160

High-resolution G-banding of chromosomes in Microtus subarvalis (Rodentia, Arvicolidae)  

PubMed

Karyotypes of six females and four males of the East European vole (Microtus subarvalis) were prepared from spleen cell cultures. G-banding of early metaphase chromosomes has allowed us to distinguish 488 bands in the haploid set of chromosomes of M. subarvalis. Based on the detailed study of chromosomes at various levels of condensation, an idiogram has been built up for the chromosomes of the East European vole. PMID:8598345

Mazurok, N A; Nesterova, T B; Zakian, S M

1995-01-01

161

Are ribosomal DNA clusters rearrangement hotspots? A case study in the genus Mus (Rodentia, Muridae)  

PubMed Central

Background Recent advances in comparative genomics have considerably improved our knowledge of the evolution of mammalian karyotype architecture. One of the breakthroughs was the preferential localization of evolutionary breakpoints in regions enriched in repetitive sequences (segmental duplications, telomeres and centromeres). In this context, we investigated the contribution of ribosomal genes to genome reshuffling since they are generally located in pericentromeric or subtelomeric regions, and form repeat clusters on different chromosomes. The target model was the genus Mus which exhibits a high rate of karyotypic change, a large fraction of which involves centromeres. Results The chromosomal distribution of rDNA clusters was determined by in situ hybridization of mouse probes in 19 species. Using a molecular-based reference tree, the phylogenetic distribution of clusters within the genus was reconstructed, and the temporal association between rDNA clusters, breakpoints and centromeres was tested by maximum likelihood analyses. Our results highlighted the following features of rDNA cluster dynamics in the genus Mus: i) rDNA clusters showed extensive diversity in number between species and an almost exclusive pericentromeric location, ii) a strong association between rDNA sites and centromeres was retrieved which may be related to their shared constraint of concerted evolution, iii) 24% of the observed breakpoints mapped near an rDNA cluster, and iv) a substantial rate of rDNA cluster change (insertion, deletion) also occurred in the absence of chromosomal rearrangements. Conclusions This study on the dynamics of rDNA clusters within the genus Mus has revealed a strong evolutionary relationship between rDNA clusters and centromeres. Both of these genomic structures coincide with breakpoints in the genus Mus, suggesting that the accumulation of a large number of repeats in the centromeric region may contribute to the high level of chromosome repatterning observed in this group. However, the elevated rate of rDNA change observed in the chromosomally invariant clade indicates that the presence of these sequences is insufficient to lead to genome instability. In agreement with recent studies, these results suggest that additional factors such as modifications of the epigenetic state of DNA may be required to trigger evolutionary plasticity. PMID:21569527

2011-01-01

162

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

PubMed

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. PMID:23767292

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

2013-01-01

163

Unusual C-band patterns in three karyotypically rearranged forms of Scapteromys (Rodentia, Cricetidae) from Brazil.  

PubMed

Chromosome studies of 30 specimens of the rodent Scapteromys collected at nine localities in southern Brazil revealed the occurrence of three karyotypic taxa with 2n = 36 (one locality), 34 (two localities), and 24 (six localities), although all three had 40 autosomal arms (AN). The G-band analysis indicated that this reduction in diploid number was mainly due to Robertsonian translocations which have occurred along a gradient, possibly in two independent evolutive routes. The C-bands occur on one autosomal pair and on the X and Y in the 2n = 36 and 34 forms and on the X and Y chromosomes only in the 2n = 24 taxon. The broad genomic reorganization which has occurred in this genus, in which the chromosomes do not have large amounts of constitutive heterochromatin, argues against the idea that a large amount of constitutive heterochromatin favors chromosome evolution and speciation. PMID:6368137

Freitas, T R; Mattevi, M S; Oliveira, L F

1984-01-01

164

Chromosomal localization of six repeated DNA sequences among species of Microtus (Rodentia).  

PubMed

C-banding and fluorescence in situ hybridization (FISH) document the distribution of constitutive heterochromatin and six highly repeated DNA families (MSAT2570, MSAT21, MSAT160, MS2, MS4 and STR47) in the chromosomes of nine species of Microtus (M. chrotorrhinus, M. rossiaemeridionalis, M. arvalis, M. ilaeus, M. transcaspicus, M. cabrerae, M. pennsylvanicus, M. miurus and M. ochrogaster). Autosomal heterochromatin is largely centromeric and contains different repeated families in different species. Similarly, large C-band positive blocks on the sex chromosomes of four species contain different repeated DNAs. This interspecific variation in the chromosomal distribution and copy number of the repeats suggests that a common ancestor to modern species contained most of the repetitive families, and that descendant species selectively amplified or deleted different repeats on different chromosomes. PMID:14606632

Modi, William S; Serdyukova, Natalya A; Vorobieva, Nadezhda V; Graphodatsky, Alexander S

2003-01-01

165

[Comparative cytogenetics of three species of South American field hamsters of the genus Akodon (Rodentia, Cricetidae)].  

PubMed

A karyological analysis of three species of South American field mice of the genus Akodon from four different localities of the Department of Tarija, Bolivian Republic, was performed. In Akodon simulator, 2n = 40 - 42, NFa = 42. The variation of the diploid number is caused by a polymorphism of the Robertsonian type involving six pairs of acrocentric chromosomes. Five variants of karyotypes were revealed. The chromosome set of A. sp. has 2n = 36, NFa = 40; in A. toba, 2n = 42 - 43, NFa = 44 - 46. The variation of the diploid number and the number of autosomal arms is caused by the polymorphism of the first autosomal pair. A comparative karyological analysis of A. simulator, A. sp., and A. toba revealed a high level of similarity of all karyotypic elements. Fifteen autosomal pairs of these three species have identical G-banding patterns; the others are involved in formation of larger chromosomes, representing one possible combination of the same chromosomal material. The set of rearrangements is limited only to tandem chromosome fusions. PMID:8647427

Aniskin, V M; Isaev, S I; Shchipanov, N A

1996-01-01

166

Evolutionary Story of a Satellite DNA from Phodopus sungorus (Rodentia, Cricetidae)  

PubMed Central

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. PMID:25336681

Paço, Ana; Adega, Filomena; Meštrovi?, Nevenka; Plohl, Miroslav; Chaves, Raquel

2014-01-01

167

Heterochromatin variation among the populations of Mus terricolor Blyth, 1851 (Rodentia, Muridae) chromosome type I  

PubMed Central

Abstract Twenty five to thirty specimens each from ten populations of Mus terricolor of the Terai and the Dooars regions of the Darjeeling foothills of West Bengal were cytogenetically analyzed using C-banding. Results showed intra- and inter- population variation of C-band positive heterochromatin ranging from very large blocks to minute amounts or even complete absence of heterochromatin. Large blocks of centromeric C-bands were found in Bidhan Nagar, Garidhura, Malbazar, Nagrakata and Maynaguri populations in most of the autosomes, while the rest of the populations had large blocks of C-bands on a few autosomes only. Such intra- and inter- population variation may be due to accumulation of C-positive heterochromatin, which has not got fixed homogeneously in all autosome pairs. X-chromosomes invariably possess a C-banded short arm a telomeric C-band at the distal end of the long arm in all populations. The entire Y-chromosome was C-band positive with slight population differences in staining intensity. The results suggest quantitative as well as qualitative variation of C-positive heterochromatin. PMID:24260696

Rudra, Mahua; Bahadur, Min

2013-01-01

168

High resolution G-banding of chromosomes in Microtus kirgisorum (Muridae, Rodentia).  

PubMed

The use of G-banding in conjunction with the pipette method of chromosome preparation has allowed 524 band resolution in chromosomes of Microtus kirgisorum. After detailed analysis of M. kirgisorum chromosomes at different stages of condensation, an ideogram has been prepared. PMID:8062598

Mazurok, N A; Rubtsov, N B; Nesterova, T B; Zakian, S M

1994-01-01

169

XY females in Microtus cabrerae (Rodentia, Microtidae): a case of possibly Y-linked sex reversal.  

PubMed

Microtus cabrerae is a species with blocks of heterochromatin on both sex chromosomes. Polymorphism caused by extensive deletions affecting these heterochromatic segments exists in both X and Y chromosomes. Of a total of 22 males and 22 females studied, four females exhibited sex pair dimorphism similar to that observed in males. C-banding techniques and preliminary data regarding inheritance support the hypothesis that these specimens are XY fertile females and that this sex reversion is most likely inherited through the Y chromosome of these females. PMID:3073913

Burgos, M; Jiménez, R; Díaz de la Guardia, R

1988-01-01

170

XY1Y2 chromosome system in Salinomys delicatus (Rodentia, Cricetidae).  

PubMed

Salinomys delicatus is considered a rare species due to its restricted and patchy distribution, poor records and low abundances. It is also the phyllotine with the lowest known diploid chromosome number (2n = 18), however its sex chromosome system has never been described. Here, we studied the chromosomes of six females and three males with bands G, C, DAPI/CMA(3) and meiosis. In males, the chromosome number was 2n = 19, with one large metacentric X-chromosome and two medium-sized acrocentrics absent in females. The karyotype of females was the same as previously described (2n = 18, FN = 32), with X-chromosomes being metacentric and the largest elements of the complement. In males, the two acrocentrics and the large metacentric form a trivalent in meiotic prophase. This indicates that S. delicatus has XY(1)Y(2) sex chromosomes, which is confirmed by G and DAPI bands. Constitutive heterochromatin (CH) is restricted to small pericentromeric blocks in all chromosomes. The X-chromosome shows the largest block of centromeric CH, which could favor the establishment of this X-autosome translocation. This sex chromosome system is rare in mammals and, compared with other phyllotine rodents, S. delicatus seems to have undergone a major chromosome restructuring during its karyotypic evolution. PMID:22105874

Lanzone, C; Rodríguez, D; Cuello, P; Albanese, S; Ojeda, A; Chillo, V; Martí, D A

2011-09-01

171

[Chromosome variation and anomalous karyotypes in the red-backed mouse Clethrionomys rufocanus (Rodentia, Microtinae)].  

PubMed

G-banding and C-banding of chromosomes were studied in populations of the red-backed mouse Clethrionomys rufocanus from 11 localities of eastern Russia. Intrapopulation polymorphism of autosome 3 caused by the deletion-duplication of the short-arm heterochromatin (2n = 56; NFa = 56-58) was demonstrated. The karyotype of Cl. rufocanus from continental populations and Sakhalin Island was shown to have a large subtelocentric chromosome of pair 3 (NFa = 58), whereas in the population from Kunashir Island, chromosomes of this pair were acrocentric (NFa = 56). One animal from the population of the Kedrovaya Pad' Reserve (Primorsk krai) had a pericentric inversion (acrocentric morphology) of the Y chromosome. In two animals, a female from the Ussuriiskii Reserve (Primorsk krai) and a male captured near the Tomari Settlement (Sakhalin Island), a pericentric inversion of one chromosome of pair 6 was found (NFa = 59). The inversion detected in the animal from the Sakhalin population was accompanied by the loss of the centromeric heterochromatin. In contrast, the inversion of the chromosome pair 6, which was found in the mouse from the Primorsk krai population, did not involve the loss of centromeric heterochromatin. Analysis of our results and data from the literature showed that the karyotype of Cl. rufocanus is not constant, as was thought earlier. The percentage of animals with abnormal karyotype (1.6%) was higher than in other groups of red-backed mice studied (0.12-0.7%). PMID:9777356

Kartavtseva, I V; Pavlenko, M V; Kostenko, V A; Cherniavski?, F B

1998-08-01

172

The origin and distribution of the Lund Y chromosome in Microtus agrestis (Rodentia, Mammalia).  

PubMed

The Lund Y (Lu-Y) chromosome of the field vole (Microtus agrestis) is distinguished from the standard Y (St-Y) by its much longer short arm. G-banding revealed that the Lu-Y originated by a pericentric inversion in the St-Y. Chromosome analysis of 297 male field voles from 92 localities in Fennoscandia. Germany, and England, in addition to data from the literature, made it possible to map the distribution area of the Lu-Y. It is restricted to the south-western parts of Sweden. The question of when and where the Lund Y population originated is discussed. Adding data from a hybrid zone (Jaarola et al. 1997) and from females, totally 491 specimens from 120 localities were analyzed without detecting any variation in chromosome number and autosome morphology. Other cases of intraspecific Y chromosome polymorphism in mammals, and the use of Y chromosome variants as population genetic markers, are discussed. PMID:9175492

Fredga, K; Jaarola, M

1997-01-01

173

The role of vibrissal sensing in forelimb position control during travelling locomotion in the rat (Rattus norvegicus, Rodentia).  

PubMed

In the stem lineage of therians, a comprehensive reorganization of limb and body mechanics took place to provide dynamic stability for rapid locomotion in a highly structured environment. At what was probably the same time, mammals developed an active sense of touch in the form of movable mystacial vibrissae. The rhythmic movements of the limbs and vibrissae are controlled by central pattern-generating networks which might interact with each other in sensorimotor control. To test this possible interaction, we studied covariation between the two by investigating speed-dependent adjustments in temporal and spatial parameters of forelimb and vibrissal kinematics in the rat. Furthermore, the possible role of carpal vibrissae in connecting the two oscillating systems was explored. We compared locomotion on continuous and discontinuous substrates in the presence and absence of the mystacial or/and carpal vibrissae across a speed range of 0.2-0.5m/s and found that a close coupling of the kinematics of the two oscillating systems appears to be precluded by their differential dependence on the animal's speed. Speed-related changes in forelimb kinematics mainly occur in temporal parameters, whereas vibrissae change their spatial excursion. However, whisking frequency is always high enough that at least one whisk cycle falls into the swing phase of the limb, which is the maximum critical period for sensing the substrate on which the forepaw will be placed. The influence of tactile cues on forelimb positional control is more subtle than expected. Tactile cues appear to affect the degree of parameter variation but not average parameters or the failure rate of limbs during walking on a perforated treadmill. The carpal vibrissae appear to play a role in sensing the animal's speed by measuring the duration of the stance phase. The absence of this cue significantly reduces speed-related variation in stride frequency and vibrissal protraction. PMID:25547567

Niederschuh, Sandra J; Witte, Hartmut; Schmidt, Manuela

2015-02-01

174

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

PubMed Central

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

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

2014-01-01

175

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

PubMed Central

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

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

2012-01-01

176

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

PubMed

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. PMID:25773245

Tesakov, A S; Lopatin, A V

2015-01-01

177

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

PubMed Central

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

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

2014-01-01

178

Competence of Peromyscus maniculatus (Rodentia: Cricetidae) as a reservoir host for Borrelia burgdorferi (Spirochaetares: Spirochaetaceae) in the wild.  

PubMed

Although capable of maintaining and transmitting Borrelia burgdorferi Johnson, Schmidt, Hyde, Steigerwalt & Brenner, the causative spirochete of Lyme disease, in the laboratory, the specific ability of deer mice, Peromyscus maniculatus Le Conte, to support this zoonosis has not been established. Demonstration that P. maniculatus is a competent reservoir host in the wild would indicate that the spread of Lyme disease is not limited to the range of the primary reservoir host, P. leucopus Rafinesque. Isle au Haut, an offshore Maine island upon which the vector tick Ixodes dammini Spielman, Clifford, Piesman & Corwin has become established, supports an isolated population of mice that are exclusively P. maniculatus. We examined the reservoir competence of this species by comparing infection rates of B. burgdorferi among juvenile ticks removed from livetrapped mice on this island with those removed from P. leucopus obtained at a mainland site endemic for Lyme disease. Equivalent rates of infection among engorged larval ticks, survival of infection through the larval-nymphal molt, and the isolation of B. burgdorferi from mice at both sites attest to the reservoir competence of P. maniculatus. PMID:8510121

Rand, P W; Lacombe, E H; Smith, R P; Rich, S M; Kilpatrick, C W; Dragoni, C A; Caporale, D

1993-05-01

179

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

NASA Technical Reports Server (NTRS)

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.

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

1990-01-01

180

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

PubMed

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. PMID:25447830

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

2015-02-01

181

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

PubMed

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. PMID:24995650

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

2014-11-01

182

Toxoplasma gondii and mast cell interactions in vivo and in vitro: experimental infection approaches in Calomys callosus (Rodentia, Cricetidae)  

Microsoft Academic Search

In the present work, we studied some qualitative and quantitative characteristics of mast cells located in the peritoneal cavity, submandibular and dorsal lymph nodes and ileum of Calomys callosus experimentally infected by Toxoplasma gondii. In uninfected animals, the majority of mast cells had similar ultra-structural characteristics, including several cytoplasmic granules with homogeneous and electron dense contents. However, after 1 h of

Gabriela Lícia S. Ferreira; José Roberto Mineo; Juliana Gonzaga Oliveira; Eloisa Amália V. Ferro; Maria Aparecida Souza; Ana Alice D. Santos

2004-01-01

183

Toxoplasma gondii and mast cell interactions in vivo and in vitro: experimental infection approaches in Calomys callosus (Rodentia, Cricetidae).  

PubMed

In the present work, we studied some qualitative and quantitative characteristics of mast cells located in the peritoneal cavity, submandibular and dorsal lymph nodes and ileum of Calomys callosus experimentally infected by Toxoplasma gondii. In uninfected animals, the majority of mast cells had similar ultra-structural characteristics, including several cytoplasmic granules with homogeneous and electron dense contents. However, after 1 h of infection, a significant influx of mast cells into peritoneal cavity was observed. The number of mast cells in this compartment decreased progressively in infected animals, and was significantly lower than the number of mast cells in control animals after 48 h of infection. Mast cells from infected animals or from purified suspensions that were infected in vitro presented significant morphological modifications, suggesting a degranulation process: cytoplasmic granules with electron dense content, fusion of the cytoplasmic granules, intracytoplasmic channels, cytoplasmic granules with flocculent material, plasma membrane rupture and granule contents in the extracellular environment. A remarkable increase in the influx of neutrophils toward the peritoneal cavity of the infected animals was observed after 12 h of infection. Moreover, this event occurred after the mast cell degranulation process took place. The relative increase in the number of mast cells and neutrophils was also followed by an increase in the number of macrophages, but there was a significant decrease in lymphocyte influx. After 48 h of infection, the parasite had spread from the peritoneal cavity to all organs examined. Also, mast cells from these organs showed evident morphological alterations, indicating the presence of the degranulation process. These results suggest that mast cells are deeply involved with the acute phase of the inflammatory response in this experimental model. PMID:14998515

S Ferreira, Gabriela Lícia; Mineo, José Roberto; Oliveira, Juliana Gonzaga; V Ferro, Eloisa Amália; Souza, Maria Aparecida; D Santos, Ana Alice

2004-02-01

184

Eimeria lancasterensis (Apicomplexa: Eimeriidae) from the eastern fox squirrel, Sciurus niger (Rodentia: Sciuridae), in north-central Texas.  

PubMed

Eimeria lancasterensis Joseph, 1969, is reported for the first time from the feces of 10 of 11 (91%) eastern fox squirrels, Sciurus niger ludovicianus, in Dallas and Johnson counties, Texas. Oocyst measurements were similar to those reported previously from the eastern gray squirrel, Sciurus carolinensis carolinensis, in Massachusetts. Except for our observation of a substieda body, oocyst morphology was identical to the original description of E. lancasterensis. PMID:2760777

McAllister, C T; Upton, S J

1989-08-01

185

A Remarkable Case of Micro-Endemism in Laonastes aenigmamus (Diatomyidae, Rodentia) Revealed by Nuclear and Mitochondrial DNA Sequence Data  

PubMed Central

L. aenigmamus is endemic to the limestone formations of the Khammuan Province (Lao PDR), and is strongly specialized ecologically. From the survey of 137 individuals collected from 38 localities, we studied the phylogeography of this species using one mitochondrial (Cyt b) and two nuclear genes (BFIBR and GHR). Cyt b analyses reveal a strong mtDNA phylogeographical structure: 8 major geographical clades differing by 5–14% sequence divergence were identified, most of them corresponding to distinct karst areas. Nuclear markers display congruent results but with a less genetic structuring. Together, the data strongly suggest an inland insular model for Laonastes population structure. With 8 to 16 evolutionary significant units in a small area (about 200×50 km) this represents an exceptional example of micro-endemism. Our results suggest that L. aenigmamus may represent a complex of species and/or sub-species. The common ancestor of all Laonastes may have been widely distributed within the limestone formations of the Khammuan Province at the end of Miocene/beginning of the Pliocene. Parallel events of karst fragmentation and population isolation would have occurred during the Pleistocene or/and the end of the Pliocene. The limited gene flow detected between populations from different karst blocks restrains the likelihood of survival of Laonastes. This work increases the necessity for a strict protection of this rare animal and its habitat and provides exclusive information, essential to the organization of its protection. PMID:23155377

Nicolas, Violaine; Herbreteau, Vincent; Couloux, Arnaud; Keovichit, Kham; Douangboupha, Bounneuang; Hugot, Jean-Pierre

2012-01-01

186

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

PubMed Central

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

Hautier, Lionel; Saksiri, Soonchan

2009-01-01

187

A new subgenus and four new species of Gliricola (Phthiraptera: Gyropidae) from the Caribbean hutias (Rodentia: Capromyidae)  

E-print Network

A new subgenus, Hutiaphilus (Phthiraptera: Gyropidae), is described for five previously named species of Gliricola (G. armatus, G. capromydis, G. cubanus, G. ewingi, and G. omahonyi) and four new species (G. rabbi, with ...

Price, Roger D.; Timm, Robert M.

1997-07-01

188

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

PubMed

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 (?(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. PMID:21644209

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

2011-01-01

189

Cuenca-Bescos, G., Laplana, C., and Canudo, I. J. (1999). Biochronological implications of the Arvicolidae (Rodentia,  

E-print Network

. (1998). Pleistocene amphibians and reptiles in Britain and Europe. Oxford Monographs on Geology of Australia and New Guinea. Special Publication. South Australia Department of Mines and Energy 5, 34

190

Capybaras (Rodentia, Hydrochoeridae, Hydrochoerinae) and their bearing in the calibration of the late Miocene-Pliocene sequences of South America  

NASA Astrophysics Data System (ADS)

Fossil capybaras were long regarded as composed of numerous taxa, each one endemic to a particular area, a scenario completely different from the one shown by the living species. The interpretation of the record according to new criteria of ontogenetic change has demonstrated that they are useful for biocorrelation because their members have short biochrons with wide geographic distribution. The levels with capybaras of each locality would represent a short lapse within the bearing lithostratigraphic units. In turn, they would also represent short intervals within the temporal extension proposed for each Stage/Age or SALMA. All the late Miocene-Pliocene records of capybaras were analyzed and a chronological scheme was built mainly for Argentina, where records are most abundant. Numerical ages and magnetostratigraphic studies contribute to correlate this scheme with the global time scale. The Chasicoan SALMA would be correlated with part of the Tortonian Stage/Age; the Huayquerian SALMA with the late Tortonian-Messinian, and it could even extend to the earliest Zanclean. The Montehermosan SALMA would be restricted to the Zanclean. The Chapadmalalan SALMA would be correlated with the late Zanclean-early Piacenzian.

Deschamps, Cecilia M.; Vucetich, María Guiomar; Montalvo, Claudia I.; Zárate, Marcelo A.

2013-12-01

191

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

PubMed Central

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

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

2014-01-01

192

Pyriproxyfen bait for control of plague vector fleas (Siphonaptera:Ceratophyllidae) on rock squirrels (Rodentia:Sciuridae)  

E-print Network

grasses such as wild rye (Elymus spp. ), acorns of shrub live oak (guercus rurbinella), flesh of a western diamond rattlesnake (Crotalur atrox), and such things as bread crusts, potato chips and Iruit left by hikers. Squirrels also feed on cottonwood...

Dietrich, Erin Bess Gabrielle

2001-01-01

193

Yellow-bellied marmots ( Marmota flaviventris ) 'in the shape space' (Rodentia, Sciuridae): sexual dimorphism, growth and allometry of the mandible  

Microsoft Academic Search

Geometric morphometrics was applied in a quantitative analysis of the morphology of the yellow-bellied marmot mandible. Five age classes were recognised by premolar toothwear, and the size and shape of the lower jaw were compared between sexes and among ages. Although the social role of adult males and females is markedly distinct, with the former mainly engaged to defend a

Andrea Cardini; Paolo Tongiorgi

2003-01-01

194

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

PubMed Central

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

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

2012-01-01

195

Phylogeny and biogeography of the Petaurista philippensis complex (Rodentia: Sciuridae), inter- and intraspecific relationships inferred from molecular and morphometric analysis.  

PubMed

With modified DNA extraction and purification protocols, the complete cytochrome b gene sequences (1140 bp) were determined from degraded museum specimens. Molecular analysis and morphological examination of cranial characteristics of the giant flying squirrels of Petaurista philippensis complex (P. grandis, P. hainana, and P. yunanensis) and other Petaurista species yielded new insights into long-standing controversies in the Petaurista systematics. Patterns of genetic variations and morphological differences observed in this study indicate that P. hainana, P. albiventer, and P. yunanensis can be recognized as distinct species, and P. grandis and P. petaurista are conspecific populations. Phylogenetic relationships reconstructed by using parsimony, likelihood, and Bayesian methods reveal that, with P. leucogenys as the basal branch, all Petaurista groups formed two distinct clades. Petaurista philippensis, P. hainana, P. yunanensis, and P. albiventer are clustered in the same clade, while P. grandis shows a close relationship to P. petaurista. Deduced divergence times based on Bayesian analysis and the transversional substitution at the third codon suggest that the retreating of glaciers and upheavals or movements of tectonic plates in the Pliocene-Pleistocene were the major factors responsible for the present geographical distributions of Petaurista groups. PMID:16414285

Yu, Farong; Yu, Fahong; Pang, Junfeng; Kilpatrick, C William; McGuire, Peter M; Wang, Yingxiang; Lu, Shunqing; Woods, Charles A

2006-03-01

196

Tick infestations of the eastern cottontail rabbit (Sylvilagus floridanus) and small rodentia in northwest Alabama and implications for disease transmission  

Microsoft Academic Search

Studies were conducted over a four-county area of northwest Alabama to determine the association of eastern cottontail rabbits with Dermacentor variabilis, the eastern United States vector of Rocky Mountain spotted fever. A secondary objective was to compare infestations of this tick on rabbits with infestations on commonly encountered rodent species as a means of determining the relative importance of each

Joseph C. Cooney; Willy Burgdorfer; Martin K. Painter; Cynthia L. Russell

197

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

NASA Astrophysics Data System (ADS)

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.

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

2008-09-01

198

Phylogeny and zoogeography of six squirrel species of the genus sciurus (mammalia, rodentia), inferred from cytochrome B gene sequences.  

PubMed

To investigate the phylogenetic relationships between the New World Sciurus and the Old World Sciurus and their biogeographic history, the partial mitochondrial cytochrome b gene sequences (1,040 base pairs) were analyzed on six Sciurus species: S. aberti, S. carolinensis, S. lis, S. niger, S. stramineus, and S. vulgaris. Phylogenetic trees (maximum parsimony, neighbor-joining, and maximum likelihood methods) commonly showed two groups with high bootstrap values (73-100%): one consisting of the New World Sciurus and the other consisting of the Old World Sciurus. Genetic distances among the New World Sciurus species were remarkably larger than that between two Sciurus species of the Old World, suggesting the earlier radiation of the New World Sciurus than the Old World Sciurus. PMID:18494597

Oshida, T; Masuda, R

2000-04-01

199

Convergent evolution of aquatic foraging in a new genus and species (Rodentia: Muridae) from Sulawesi Island, Indonesia.  

PubMed

The island of Sulawesi, in Indonesia, lies at the crossroads of the Indo-Australian Archipelago and has remained isolated from the Asian (Sunda) and Australian (Sahul) continental shelves for at least the last 10 million years. Of the 50 native species of rodents on Sulawesi, all are endemic and represent the evolution of a variety of ecological and morphological forms within the Muridae and Sciuridae. Carnivorous rodents have evolved, perhaps independently, in Muridae from the Philippines, Sulawesi, and Sahul, but semi-aquatic murids are only known from Sahul. Here we describe a new genus and species of insectivorous water rat from Sulawesi. Phylogenetic analyses demonstrate that it is related to the shrew rats of Sulawesi and represents an origin of aquatic carnivory that is independent from the evolution of water rats on Sahul. Many areas of Sulawesi have not been surveyed systematically and current lists of mammal species are likely to dramatically underestimate actual diversity. PMID:24943633

Rowe, Kevin C; Achmadi, Anang S; Esselstyn, Jacob A

2014-01-01

200

A new species of Spirura Blanchard, 1849 (Nematoda: Spiruridae) parasite of Heliosciurus gambianus and Xerus erythropus (Rodentia: Sciuridae) in Senegal.  

PubMed

A new species of Spirura is described from the stomach of Heliosciurus gambianus and Xerus erythropus (Sciuridae). Considering the number of preanal papillae of males, Babero (1973 ) and Giannetto and Canestri Trotti (1995) proposed the subdivision of the genus into 2 groups; those with 4 pairs of preanal papillae (25 species) and with more than 4 pairs of preanal papillae (4 species). Spirura mounporti n. sp. belongs to the second, with 5 pairs of preanal papillae, and differs from Spirura infundibuliformis (McLeod, 1933) Anderson et al., 1993 , Spirura zapi ( Erickson, 1938 ) Chabaud et al., 1965 , Spirura leiperi Gupta and Trivedi, 1985, and Spirura michiganensis Sandground, 1935 in the number of pairs of pre-cloacal papillae. The new species further differs from other species of the genus in having 21 caudal papillae, in the ratio of spicules:body length, and in its morpho-anatomical characters. PMID:23795669

Diouf, Malick; Seck, Cheikh Ahmadou Bamba; Bâ, Cheikh Tidiane; Quilichini, Yann; Marchand, Bernard

2013-12-01

201

ABIOTIC FACTORS AFFECTING THE DEVELOPMENT OF FLEAS (SIPHONAPTERA) OF CALIFORNIA GROUND SQUIRRELS (RODENTIA: SCIURIDAE) IN SOUTHERN CALIFORNIA, USA  

Microsoft Academic Search

The California ground squirrel, Spermophilus beecheyi (Richardson), is a reservoir of bubonic plague throughout most of its range. Three species of fleas occur on these animals; Oropsylla montana (Baker), Hoplopsyllus anomalus (Baker), and the sticktight flea, Echidnophaga gallinacea (Westwood). Despite the importance of these fleas to plague transmission, there is only limited information regarding their biology, ecology, and how this

MARCO E. METZGER; MICHAEL K. RUST

202

Teasing apart socially-induced infertility in non-reproductive female Damaraland mole-rats, Fukomys damarensis (Rodentia: Bathyergidae).  

PubMed

The Damaraland mole-rat is a subterranean mammal exhibiting extreme reproductive skew with a single reproductive female in each colony responsible for procreation. Non-reproductive female colony members are physiologically suppressed while in the colony, exhibiting reduced concentrations of plasma luteinizing hormone (LH) and a decreased response of the pituitary, as measured by the release of bioactive LH, to an exogenous dose of gonadotrophin releasing hormone (GnRH). Removal of the reproductive female from the colony results in an elevation of LH and an enhanced response of the pituitary to a GnRH challenge in non-reproductive females comparable to reproductive females, implying control of reproduction in these individuals by the reproductive female. The Damaraland mole-rat is an ideal model for investigating the physiological and behavioral mechanisms that regulate the hypothalamo-pituitary-gonadal axis. In contrast, we know less about the control of reproduction at the level of the hypothalamus. The immunohistochemistry of the GnRH system of both reproductive and non-reproductive female Damaraland mole-rats has revealed no significant differences with respect to morphology, distribution or numbers of immunoreactive GnRH perikarya. We examined whether the endogenous opioid peptide beta-endorphin was responsible for the inhibition of the release of the GnRH from the neurons indirectly by measuring LH concentrations in these non-reproductive females following single, hourly and 8 hourly injections of the opioid antagonist naloxone. The results imply that the endogenous opioid peptide, beta-endorphin, is not responsible for the inhibition of GnRH release from the perikarya in non-reproductive females. Preliminary data examining the circulating levels of cortisol also do not support a role for circulating glucocorticoids. The possible role of kisspeptin is discussed. PMID:22182323

Bennett, Nigel C

2011-12-01

203

Paranoplocephala maseri n. sp. (Cestoda, Anoplocephalidae), a parasite of sagebrush voles Lemmiscus curtatus (Rodentia) in the USA  

Microsoft Academic Search

Paranoplocephala maseri n. sp. is described from Lemmiscus curtatus (Cope) in the USA. The new species is related to Paranoplocephala omphalodes (Hermann, 1783), P. caucasica (Kirschenblat, 1938), P. kirbyi Voge 1948, P. microti (Hansen, 1947) and P. macrocephala (Douthitt, 1915) sensu Genov et al. (1996). P. maseri n. sp. differs from P. omphalodes in the position of the genital pores,

František Tenora; András Gubányi; Éva Murai

1999-01-01

204

Paranoplocephala maseri n. sp. (Cestoda, Anoplocephalidae), a parasite of sagebrush voles Lemmiscus curtatus (Rodentia) in the USA.  

PubMed

Paranoplocephala maseri n. sp. is described from Lemmiscus curtatus (Cope) in the USA. The new species is related to Paranoplocephala omphalodes (Hermann, 1783), P. caucasica (Kirschenblat, 1938), P. kirbyi Voge 1948, P. microti (Hansen, 1947) and P. macrocephala (Douthitt, 1915) sensu Genov et al. (1996). P. maseri n. sp. differs from P. omphalodes in the position of the genital pores, testes and cirrus-sac; from P. caucasica, in which there is an unarmed cirrus, in both the distribution and larger number of testes; from P. kirbyi in the distribution of the testes, the position of the genital pores and egg dimensions; from P. microti in the distribution and smaller number of testes, the smaller egg dimensions and the position of the genital pores; and from P. macrocephala in the position of genital pores and cirrus-sac. PMID:10612439

Tenora, F; Gubányi, A; Murai, E

1999-02-01

205

NEW SPECIES OF AROSTRILEPIS (EUCESTODA: HYMENOLEPIDIAE) IN MEMBERS OF CRICETIDAE AND GEOMYIDAE (RODENTIA) FROM THE WESTERN NEARCTIC  

Technology Transfer Automated Retrieval System (TEKTRAN)

Specimens originally identified as Arostrilepis horrida from the Nearctic are revised, contributing to the recognition of a complex of cryptic species distributed across the Holarctic region. Previously unrecognized species are described based on specimens in rodents of the families Cricetidae (Neot...

206

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

PubMed

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

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

207

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

PubMed

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. PMID:17714301

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

2007-09-01

208

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

PubMed

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. PMID:15012954

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

2004-03-01

209

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

USGS Publications Warehouse

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.

Andersen, Douglas C.; MacMahon, James A.

1981-01-01

210

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

PubMed

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. PMID:17354413

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

2004-12-01

211

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

PubMed Central

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

Davis, Edward Byrd

2005-01-01

212

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

Microsoft Academic Search

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

Edward Byrd Davis

2005-01-01

213

Sexual size dimorphism in ground squirrels (Rodentia: Sciuridae: Marmotini) does not correlate with body size and sociality  

PubMed Central

Introduction Sexual size dimorphism (SSD) is a widespread phenomenon in animals including mammals. It has been demonstrated that across species, the direction and magnitude of sexual dimorphism in body size often corresponds to social systems. Moreover, many animal lineages conform to “Rensch’s rule”, which states that male-biased SSD increases with body size. We tested whether considerable differences in sociality and large variation in body size were connected with the evolution of SSD in the structural body size of ground squirrels, an otherwise ecologically relatively homogenous group of terrestrial rodents. Results We found the general trend of male-biased SSD in ground squirrels, however, male size increases nearly perfectly isometrically with female size among species and sociality does not explain departures from this relationship. Species with different sociality grades significantly differ in body size, with the most social species tending to be the largest. Conclusions We suggest that lack of conformity with Rensch´s rule in ground squirrels may be attributed to their low variation in SSD, and briefly discuss three potential causes of small magnitude of SSD in the structural size in rodents: low selection on SSD in structural dimensions, ontogenetic and genetic constraints and the existence of ecological/selection factors preventing the evolution of extensive SSD. PMID:23672689

2013-01-01

214

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

PubMed

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

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

2014-01-01

215

Invertebrate dispersal by aquatic mammals: a case study with nutria Myocastor coypus (Rodentia, Mammalia) in Southern France  

Microsoft Academic Search

Many freshwater invertebrates rely on vectors for their passive dispersal. A wide array of vectors has already been investigated,\\u000a but dispersal mediated by aquatic mammals remains largely unknown. Since nutria (Myocastor coypus Molina, 1782) live in a variety of aquatic habitats and frequently move around between these water bodies, they have the\\u000a opportunity to transport hitch-hiking aquatic invertebrates along with

Aline Waterkeyn; Olivier Pineau; Patrick Grillas; Luc Brendonck

2010-01-01

216

Modelling the distribution of an introduced species: The coypu Myocastor coypus (Mammalia, Rodentia) in Piedmont region, NW Italy  

Microsoft Academic Search

Model?based analyses of species–habitat relationships can help to clarify which factors influence the establishment and spread of species. The coypu (Myocastor coypus) is a semi?aquatic rodent native to South America, which has been introduced worldwide, including Italy. We used logistic regression to analyse the species distribution according to habitat attributes of agro?ecosystems in Piedmont Region. The resulting model correctly predicted

S. Bertolino; B. Ingegno

2009-01-01

217

Padrão de divisão e distribuição das artérias mesentéricas no ratão-do-banhado (Myocastor coypus - Rodentia: Mammalia)  

Microsoft Academic Search

celíaca (70%), ou em tronco comum com esta (30%); b) os ramos diretos da artéria mesentérica cranial são as artérias pancreaticoduodenal caudal (100%), cólica média (100%), duodenojejunal (90%), pancre- ática (10%), hepática (10%), cólica direita (100%), jejunais (100%), ileocólica (100%) e ileal (100%). A artéria mesentérica caudal surge da face ventral da aorta abdominal, imediatamente cranial à emergência das artérias

Gilberto Valente Machado; Pedro Renato Gonçalves; Adelvino Parizzi

218

Peromyscus perfulvus (Rodentia: Cricetidae) CORNELIO SA NCHEZ-HERNA NDEZ, GARY D. SCHNELL, AND MARIA DE LOURDES ROMERO-ALMARAZ  

E-print Network

(Carleton 1989; Hooper 1968; Lee and Elder 1977; Schmidly et al. 1985). P. perfulvus was considered be with P. simulus (Osgood 1945). A later study (Hooper 1955) based on samples from various parts were further partitioned into groups (Hooper 1958). This resulted in P. perfulvus being referred

Hayssen, Virginia

219

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

PubMed Central

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

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

220

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

PubMed

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. PMID:22349983

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

221

The taxonomic status of Echinococcus cruzi Brumpt and Joyeux, 1924 (Cestoda: Taeniidae) from an agouti (Rodentia: Dasyproctidae) in Brazil.  

PubMed

Paratype material of Echinococcus cruzi Brumpt and Joyeux, 1924, described from an agouti, Dasyprocta leporina (L.), in Brazil, was compared with Echinococcus oligarthrus (Diesing, 1863), of which the larval stage occurs also in agoutis and other rodents in South America and Central America. Comparisons of the larval cestodes (metacestodes) showed that the rostellar hooks from protoscolices of the two taxa corresponded in form, and their slightly greater lengths in E. cruzi were considered to be of no taxonomic significance. They agreed as well in other morphological characteristics. Echinococcus cruzi was compared also with the other neotropical species, E. vogeli Rausch and Bernstein, 1972, Based on these comparisons and in agreement with the earlier conclusion of Cameron (1926), E. cruzi Brumpt and Joyeux, 1924 is placed in synonymy with E. oligarthrus (Diesing, 1863). PMID:6470893

Rausch, R L; D'Alessandro, A; Ohbayashi, M

1984-04-01

222

Phylogenetic relationships in the Niviventer-Chiromyscus complex (Rodentia, Muridae) inferred from molecular data, with description of a new species  

PubMed Central

Abstract Based on molecular data for mitochondrial (Cyt b, COI) and nuclear (IRBP, GHR) genes, and morphological examinations of museum specimens, we examined diversity, species boundaries, and relationships within and between the murine genera Chiromyscus and Niviventer. Phylogenetic patterns recovered demonstrate that Niviventer sensu lato is not monophyletic but instead includes Chiromyscus chiropus, the only previously recognized species of Chiropus. To maintain the genera Niviventer and Chiropus as monophyletic lineages, the scope and definition of the genus Chiromyscus is revised to include at least three distinct species: Chiromyscus chiropus (the type species of Chiromyscus), Chiromyscus langbianis (previously regarded as a species of Niviventer), and a new species, described in this paper under the name Chiromyscus thomasi sp. n. PMID:25493050

Balakirev, Alexander E.; Abramov, Alexei V.; Rozhnov, Viatcheslav V.

2014-01-01

223

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

PubMed Central

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

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

2013-01-01

224

Numerical and structural variations of the X chromosomes and no. 2 autosomes in mandarin vole, Microtus mandarinus (Rodentia).  

PubMed

Here we describe our studies on Microtus mandarinus faeceus of Jiangyan in Jiangsu province of China. By karyotype and G-banding analysis we have found variation in chromosome number and polymorphisms of the X chromosome and the second pair of autosomes of the subspecies. Chromosome number of the subspecies is 2n=47-50. The subspecies has three kinds of chromosomal sex: XX, XO and XY, among which one of the X chromosomes is subtelocentric (X(ST)) and the other is metacentric (X(M)). After comparing karyotypes of different subspecies, we found the specific cytogenetic characteristics of Microtus mandarinus, that is they have three kinds of chromosomal sex: XX, XO and XY; X chromosomes are heteromorphic; the chromosome number of female individuals are one less than male individuals; chromosome number of XX individuals are equal to that of XO ones. We hypothesize that Robertsonian translocation is the main reason of the polymorphism of the second pair of autosomes and variety of chromosome number, and it also causes the chromosome number evolution in different subspecies of Microtus mandarinus. PMID:17362346

Zhu, Bicai; Dong, Yuwei; Gao, Junfang; Li, Peiqing; Pang, Yonghonh; Liu, Huanmin; Chen, Hong

2006-12-01

225

[Genogeographic variability and genetic differentiation of the root vole (Microtus oeconomus Pallas, 1776, Cricetidae, Rodentia) from the Kuril Islands].  

PubMed

Electrophoretic analysis of 12 enzyme systems and 3 nonenzyme proteins (in all, 24 interpretable loci) was carried out for Microtus oeconomus from ten Kuril islands, Kamchatka Peninsula, and the vicinity of the city of Magadan. Gene geographic variation was examined and the coefficients of genetic variation and differentiation were estimated. The inter-population allozyme differentiation was low (DNEI, 1972 not higher than 0.053) and caused by variation in the allele frequencies of polymorphic loci. The greatest genetic distances were found between the populations belonging to different subspecies. Allozyme differentiation of Far Eastern M. oeconomus and M. fortis are discussed in relation to the data on the age of the island isolation and paleontological records. Karyological analysis (G-, C-, and NOR-banding) demonstrated the absence of differences between M. oeconomus from Kamchatka and the vicinity of Magadan. PMID:14658341

Frisman, L V; Kartavtseva, I V; Kostenko, V A; Sheremet'eva, I N; Cherniavski?, F B

2003-10-01

226

[Karyological and allozyme variability of far eastern voles Microtus fortis Büchner, 1889 (Cricetidae, Rodentia) from the Russian Far East].  

PubMed

Karyological (G-, C-, and NOR-banding) and allozyme analyses were carried out for island and continental populations of the vole Microtus fortis from the Far East of Russia. Variability of the autosome pair 7 was found. The presence of variation in the number of telomere heterochromatin blocks in the populations of Far Eastern voles was confirmed. NOR-staining of the Far Eastern vole chromosomes was carried out, showing stability of the number and the positions of the nucleolus organizer regions. Ten enzyme systems and three non-enzyme proteins (controlled in total by 25 interpretable loci) were examined in the Far Eastern vole from the island and continental populations. All of the loci were shown to be monomorphic, except for one esterase locus, which exhibited polymorphism at the intrapopulation and interpopulation levels. The issue of distribution of the Far Eastern vole subspecies is discussed. It is suggested that M. fortis pelliceus occurs not only in the Russian Far East, but also in Northern Transbaikalia. PMID:16871789

Sheremet'eva, I N; Kartavtseva, I V; Frisman, L V

2006-06-01

227

Tandem and centric fusions in the chromosomal evolution of the South American phyllotines of the genus Auliscomys (Rodentia, cricetidae).  

PubMed

The karyotypes of three of the four extant species of the genus Auliscomys (A. micropus, living in central [2n = 32, NF = 34] and southern [2n = 34, NF = 36, 37] Chile; A. sublimis [2n = 28, NF = 32] and A. boliviensis [2n = 22, NF = 32], which inhabit the Andean Altiplano) were analyzed. Comparisons of G-, C-, and AgNOR-banded karyotypes showed that extensive conservation of entire chromosomes and chromosomal regions had occurred during the evolution of this genus, with centromeretelomere tandem fusions and centric fusions probably being the most frequent chromosome changes. A chromosomal phylogeny, based on the chromosome homoeologies detected and parsimonious analysis of the nature and distribution of the inferred chromosomal changes, is proposed. This hypothetical phylogeny assumes that the ancestral telocentric karyotype would have undergone three consecutive tandem fusions, first originating the 2n = 32 (NF = 34) karyomorph exhibited by present-day specimens of A. micropus captured in central Chile and then the 2n = 28 (NF = 32) karyotype of A. sublimis. Subsequent centric fusions involving the tandem-fusion products would presumably have generated the 2n = 22 (NF = 32) A. boliviensis karyotype. Assuming some conditions related to early geographic distribution, this chromosomal phylogeny is in agreement with a paleogeographic model, which explains the present distribution of living Auliscomys species mainly on the basis of geologic and climatic events.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1395723

Walker, L I; Spotorno, A E

1992-01-01

228

A geologic investigation of Longhorn Cavern  

E-print Network

Rodentia Sciurus Citellus Geomys hursarius Perognathus hispidus merriami Reithrodontomys montanus Peromyscus Onychomys leucogaster Sigmodon hispidus BLACK FILL RED FILL LONGHORN 38 TABLE 3. Continued Carnivore Canis Ursus americanus...

Walters, Victoria Lynn

1992-01-01

229

Effect of six antiretroviral drugs (delavirdine, stavudine, lamivudine, nelfinavir, amprenavir and lopinavir/ritonavir in association) on albino pregnant rats (Rattus norvegicus Albinus, Rodentia, Mammalia): biological assay.  

PubMed

Objective: To compare the chronic effects of antiretrovirals (lamivudine, stavudine, delavirdine, nelfinavir, amprenavir and an association of lopinavir/ritonavir) on albino pregnant rats.Design: Review.Setting: Department of Obstetrics, Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil.Methods: This was a comparative retrospective study formed by 18 groups of 10 pregnant rats each, which were nearly three months of age and weighed 200 g. All of them were medicated every day using a stomach probe, while the control group was given 1 mL of distilled water. The study groups received lamivudine (at 5, 15 and 45 mg/kg/day); stavudine (at 1, 3 and 9 mg/kg/day); nelfinavir (at 40, 120 and 360 mg/kg/day); amprenavir (at 46, 138 and 414 mg/kg/day); lopinavir/ritonavir (at 12.8/3.2, 38.4/9.6 and 115/28.8 mg/kg/day) and delavirdine (at 20 and 60 mg/kg/day). These represented 1, 3 and 9 times the human therapeutic dose, except for the last drug, for which the 9-times dose was not used. Maternal, litter and placental weights, implantation and reabsorption numbers, major external fetal malformations and fetal and maternal deaths were evaluated. The Kruskal-Wallis test was used to compare quantitative variables and the chi-square test was used to compare qualitative variables.Results: At all three doses, stavudine increased the maternal weight (p=0.001), while lamivudine at 3- and 9-times doses reduced it (p<0.001). Amprenavir at all of the doses, and lopinavir/ritonavir at 3- and 9-times doses, caused higher rates of maternal death (p<0.001). Regarding the fetuses, none of the antiretroviral drugs studied were harmful with regard to implantation, reabsorption, teratogenity and mortality (p>0.05). Stavudine at all doses reduced the litter weights (p<0.001); however, lamivudine at the usual and 3-times doses, delavirdine at 3-times dose, and amprenavir at 3-times dose increased the litter weight (p<0.001).Conclusion: In the maternal compartment, we observed lethal toxicity in the pregnant rats that received amprenavir and ritonavir/lopinavir; and maternal weight change with lamivudine and stavudine. In the fetal compartment, adverse effects were observed in relation to litter weight from stavudine, lamivudine, delavirdine and amprenavir.Keywords: pregnant rats, antiretroviral drugs, teratology, biological assay. PMID:25398151

Nakamura, M U; Araujo, E Júnior; Simões, J M; Oliveria, R M Filho; Kulay, L Júnior

2014-01-01

230

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

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 (?n) 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 (?n = -2.9), transformed into induced grasslands. Additionally, we have observed the porcupine (since 2011) in semi-deciduous (?n = -0.87) and tropical dry (?n = -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. PMID:25720182

Lorenzo, Consuelo; Sántiz, Eugenia C; Navarrete, Darío A; Bolaños, Jorge

2014-12-01

231

Description of two new species of Nippostrongylinae (Nematoda: Heligmonellidae) coparasites in three sympatric species of Mastomys spp. (Rodentia: Muridae) from Senegal.  

PubMed

Two new species of heligmosomoid Trichostrongylina nematodes belonging to the genera Neoheligmonella Durette-Desset, 1970 and Heligmonina Baylis, 1928 are described. They are parasitic in the small intestine of three species of Mastomys from Senegal living in sympatry: M. natalensis (Smith, 1834), M. erythroleucus (Temminck, 1853) and M. huberti (Wroughton, 1909). Neoheligmonella granjoni n. sp. is closely related to three species from Senegal. They concern: N. bai Diouf & Durette-Desset, 2002 and N. dielmensis Diouf, Bâ & Durette-Desset, 1998, both parasitic in Arvicanthis niloticus Geoffroy, 1903 and N. mastomysi Diouf et al., 1998, a parasite of M. erythroleucus. N. granjoni n. sp. differs from these species by having 15 cuticular ridges at mid-body versus 13, a large carene and spicules taking up 10-15% of body length versus 5.3-7.1%. Heligmonina kanei n. sp. differs from the most related species H. kotoensis Diouf, Daouda & Durette-Desset 2005, a parasite of M. natalensis from Benin in the following features: spicules taking up 11.6% of body length on average versus 16.8%; a female tail three times longer than the distance anus-vulva versus a tail of equivalent size to this distance. In N. granjoni n. sp., where the material is abundant in all three hosts, the infra-specific variations observed (morphological or morphometrical) were not related to the host species. This is the first report of the genera Neoheligmonella and Heligmonina in M. huberti. The relevance of the phenomenon of host capture concerning the evolution of these two genera is confirmed. PMID:19202761

Durette-Desset, M C; Brouat, C; Diouf, M; Duplantier, J M

2008-12-01

232

[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

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. PMID:25782276

2014-01-01

233

[Experimental hybridization of voies of the genus Microtus s.l. M. socialis with species of the group arvalis (Mammalia, Rodentia)].  

PubMed

The results of interspecific crosses of the social vole Microtus socialis with the Altai vole M. obscurus, the East European vole M. rossiaemeridionalis, and the Transcaspian vole M. transcaspicus are presented. The role of the sperm head structure in the reproductive isolation of this species was studied. Hybrids were obtained in five of the six crossing combinations. It is established that significant differences in the sperm head shape in the social vole and in arvalis group species do not prevent fertilization. The sterility of hybrids indicates the existence of postcopulative mechanisms of reproductive isolation. PMID:25739313

Koval'skaia, Iu M; Savinetskaia, L E; Aksenova, T G

2014-01-01

234

Stratigraphic context and paleoenvironmental significance of minor taxa (Pisces, Reptilia, Aves, Rodentia) from the late Early Pleistocene paleoanthropological site of Buia (Eritrea).  

PubMed

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. PMID:23159190

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

235

Species of Eimeria (Apicomplexa: Eimeriidae) from tree squirrels (Sciurus niger) (Rodentia: Sciuridae) and analysis of the ITS1, ITS2, and 5.8S rDNA.  

PubMed

During the winter of 2004, 48 fecal samples were collected from live-trapped fox squirrels (Sciurus niger) from central Wyoming (Natrona County) and examined for species of Eimeria. Two species, Eimeria lancasterensis (prevalence, 65%) and Eimeria ontarioensis (prevalence, 27%), were identified. Genomic DNA sequences ITS1 and ITS2 were amplified, cloned, and sequenced. Additional sequences from E. lancasterensis isolated from a Delmarva fox squirrel (Sciurus niger cinereus) collected on Chincoteague Island, Virginia, were also identified. Comparison of pairwise distances suggests that E. lancasterensis from Wyoming and Virginia are conspecific. Maximum Parsimony tree construction identified 2 lineages, one E. ontarioensis and one E. lancasterensis; and both lineages had a strong bootstrap support (100%). The Maximum Parsimony analysis was unable to resolve the Wyoming and Virginia strains. PMID:19245280

Motriuk-Smith, Dagmara; Seville, R Scott; Oliver, Clinton E; Hofmann, Danielle L; Smith, Arik W

2009-02-01

236

Helminth parasites in native and invasive mammal populations: comparative study on the Barbary ground squirrel Atlantoxerus getulus L. (Rodentia, Sciuridae) in Morocco and the Canary Islands  

Microsoft Academic Search

A total of 51 and 21 adults of Barbary ground squirrels (Atlantoxerus getulus) were trapped during May–July 2006 from the introduced populations on Fuerteventura Island (Canary Islands) and the native\\u000a populations in Morocco, respectively. One trematode, 1 cestode and 4 nematode species were recovered belonging to five families:\\u000a Brachylaima sp. (Brachylaimidae), Catenotaenia chabaudi (Catenotaeniidae), Protospirura muricola (Spiruridae), Dermatoxys getula and

Marta López-Darias; Alexis Ribas; Carlos Feliú

2008-01-01

237

Lineage-Specific Responses of Tooth Shape in Murine Rodents (Murinae, Rodentia) to Late Miocene Dietary Change in the Siwaliks of Pakistan  

PubMed Central

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. PMID:24155885

Kimura, Yuri; Jacobs, Louis L.; Flynn, Lawrence J.

2013-01-01

238

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

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

Lopes, C M; Ximenes, S S F; Gava, A; de Freitas, T R O

2013-01-01

239

The evolution of nuclear microsatellite DNA markers and their flanking regions using reciprocal comparisons within the African mole-rats (Rodentia: Bathyergidae)  

E-print Network

Microsatellites are repetitive DNA characterized by tandem repeats of short motifs (2 � 5 bp). High mutation rates make them ideal for population level studies. Microsatellite allele genesis is generally attributed to strand slippage...

Ingram, Colleen Marie

2006-10-30

240

Evaluation of the fat-tailed gerbil, Pachyuromys duprasi (Rodentia: Gerbillidae), as a new animal model for studies of Leishmania major infection and transmission.  

PubMed

The fat-tailed gerbil Pachyuromys duprasi is a common burrowing rodent found across the northern Sahara Desert from Morocco to Egypt. There is overlap in the geographical distribution and ecological habitats of P. duprasi, several Old World Leishmania species, and numerous sand fly vectors of Leishmania, but there are no records that document the natural occurrence of this gerbil with any species of Leishmania or phlebotomine sand fly. Experiments were conducted to determine its potential as a natural host and laboratory animal model for Leishmania major. Captive-born P. duprasi were inoculated subcutaneously (s.c.) in the tail with promastigotes or amastigotes of an Egyptian strain of L. major and monitored for signs of infection. Local swelling and erythema was visible 10-12 days after amastigote inoculation, and within 3-4 weeks swelling had increased tail widths by up to 78%. Infections progressed more slowly and less conspicuously following inoculation with promastigotes. Tissue density of amastigotes in the gerbil's tail lesions after inoculating with either stage of L. major was significantly lower than that produced in the footpads of BALB/c mice by the same parasite and incubation period. Laboratory transmission of L. major to P. duprasi by sand fly bite was demonstrated and acquisition of L. major, by bite, from tail lesions of infected P. duprasi to laboratory-reared Phlebotomus papatasi was also achieved with 10% of biting flies developing promastigote infections. The acquisition and development of L. major infections in P. papatasi after biting an infected P. duprasi and the susceptibility of P. duprasi to L. major delivered at low densities by sand fly bites indicate that fat-tailed gerbils could serve as a natural host and reservoir of L. major. PMID:23697770

Hanafi, Hanafi A; Fryauff, David J; Kittell, Cornel E

2013-09-01

241

Population history of the Hispaniolan hutia Plagiodontia aedium (Rodentia: Capromyidae): testing the model of ancient differentiation on a geotectonically complex Caribbean island.  

PubMed

Hispaniola is a geotectonically complex island consisting of two palaeo-islands that docked c. 10 Ma, with a further geological boundary subdividing the southern palaeo-island into eastern and western regions. All three regions have been isolated by marine barriers during the late Cenozoic and possess biogeographically distinct terrestrial biotas. However, there is currently little evidence to indicate whether Hispaniolan mammals show distributional patterns reflecting this geotectonic history, as the island's endemic land mammal fauna is now almost entirely extinct. We obtained samples of Hispaniolan hutia (Plagiodontia aedium), one of the two surviving Hispaniolan land mammal species, through fieldwork and historical museum collections from seven localities distributed across all three of the island's biogeographic regions. Phylogenetic analysis using mitochondrial DNA (cytochrome b) reveals a pattern of historical allopatric lineage divergence in this species, with the spatial distribution of three distinct hutia lineages biogeographically consistent with the island's geotectonic history. Coalescent modelling, approximate Bayesian computation and approximate Bayes factor analyses support our phylogenetic inferences, indicating near-complete genetic isolation of these biogeographically separate populations and differing estimates of their effective population sizes. Spatial congruence of hutia lineage divergence is not however matched by temporal congruence with divergences in other Hispaniolan taxa or major events in Hispaniola's geotectonic history; divergence between northern and southern hutia lineages dates to c. 0.6 Ma, significantly later than the unification of the palaeo-islands. The three allopatric Plagiodontia populations should all be treated as distinct management units for conservation, with particular attention required for the northern population (low haplotype diversity) and the south-western population (high haplotype diversity but highly threatened). PMID:22404699

Brace, Selina; Barnes, Ian; Powell, Adam; Pearson, Rebecca; Woolaver, Lance G; Thomas, Mark G; Turvey, Samuel T

2012-05-01

242

Comparative chromosome mapping of the rRNA genes and telomeric repeats in three Italian pine voles of the Microtus savii s.l. complex (Rodentia, Cricetidae).  

PubMed

The Microtus (Terricola) savii s. l. complex is a group of five species/subspecies of the Italian pine voles, which diverged at different times either with or without chromosomal differentiation. The evidence of chromosomal diversification has so far concerned the shape of the sex chromosomes, especially the X chromosome. Three taxa of the group, Microtus savii savii, Microtus savii nebrodensis, and Microtus savii tolfetanus have identical karyotypes with metacentric X chromosomes. The X chromosomes of Microtus brachycercus and Microtus brachycercus niethammericus are, respectively, subtelocentric and acrocentric in shape. The Microtus savii complex has been long an object of conventional karyological studies, but comparative molecular cytogenetic data were completely missing. Therefore, we conducted a comparative chromosomal mapping of rRNA genes (rDNA) and telomeric repeats in three of the five taxa of the group: Microtus savii savii, Microtus savii nebrodensis, and Microtus brachycercus niethammericus, each of which belongs to a distinct mitochondrial clade.The survey revealed that differentiation of the clades was accompanied by remarkable changes with regard to the number and locations of the rDNA sites. Thus, Microtus savii savii and Microtus savii nebrodensis have especially high numbers of rDNA sites, which are located in the centromeric regions of, correspondingly, 18 and 13 chromosome pairs, whereas Microtus brachycercus niethammericus shows variable (8-10) and heteromorphic rDNA sites on both centromeric and telomeric regions. Interstitial telomeric sites (ITS), which are believed to indicate possible breakpoints of recurring chromosomal rearrangements, are present on the largest biarmed chromosomes and on the metacentric X chromosomes in Microtus savii savii and Microtus savii nebrodensis. These preliminary results are discussed in the context of recent advances in phylogeny of the group, as well as the rDNA genomic organization and X chromosome rearrangements in the genus Microtus. PMID:24260633

Gornung, Ekaterina; Bezerra, Alexandra M R; Castiglia, Riccardo

2011-01-01

243

Vexillata liomyos n. sp. (Nemata: Ornithostrongylidae) from Liomys pictus (Rodentia: Heteromyidae) from Mexico, with comments on the synlophe of Vexillata armandae.  

PubMed

Individuals of a new species of Vexillata were collected from the small intestines of Liomys pictus from the Estaci6n de Biología Chamela, in Jalisco State, Mexico. The new species shows an array of characters that allow us to recognize it as a member of Vexillata; however, it can be distinguished from other species of the genus in that males possess an asymmetrical caudal bursa, females possess a characteristic cuticular inflation at the level of the ovijector, and both sexes possess a synlophe with 9 ridges at the midbody. Additional detail of the synlophe of Vexillata armandae Gardner et al., 1994 from Chaetodipus hispidus in New Mexico shows that both sexes have 12 cuticular ridges just posterior to the cephalic inflation, and in the posterior region of the body, females have 9 ridges of equal size while males possess 11 equal-sized ridges. In both sexes, the carene disappears at the posterior end of the body. PMID:11426731

Falcón-Ordaz, J; Gardner, S L; Pérez-Ponce de León, G

2001-06-01

244

Trichospirura aethiopica n. sp. (Nematoda: Rhabdochonidae) from Malacomys longipes (Rodentia: Muridae) in Gabon, first record of the genus in the Ethiopian Realm  

PubMed Central

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 ?m. 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

Bain, Odile; Junker, Kerstin

2013-01-01

245

Isolation of 18 polymorphic microsatellite loci from the North American red squirrel, Tamiasciurus hudsonicus (Sciuridae, Rodentia), and their cross-utility in other species  

Microsoft Academic Search

We isolated 18 polymorphic microsatellite loci to be used for pedigree analysis in a wild population of North American red squirrels, Tamiasciurus hudsonicus . Allelic diversity and observed heterozygosity ranged from six to 13 and 0.39 to 0.89, respectively, in a sample of 93 individuals. Up to 13 sets of primers also amplify in other rodent species.

MELISSA R. GUNN; DEBORAH A. DAWSON; ANDREW LEVISTON; KATIE HARTNUP; COREY S. DAVIS; CURTIS STROBECK; JON SLATE; DAVID W. COLTMAN

2005-01-01

246

Changes in aquatic plant communitieson the island of Valaam due to invasion by the muskrat Ondatra zibethicus L.(Rodentia, Mammalia)  

Microsoft Academic Search

Muskrat invaded Valaam Island (Northern part of European Russia) in the 1970s. Aquatic plant communities of 1962 and 1993 were compared on the same plots. Quantitative changes were tested with the help of jack-knifing estimates of most known inventory (a-) diversity indicators. Qualitative transformations were assessed using ß-diversity values. The results demonstrated substantially more discriminant ability of diversity measures than

Vladimir V. Smirnov; Kirill Tretyakov

1998-01-01

247

ESTRUTURA DE COMUNIDADES DE PEQUENOS MAMÍFEROS E DENSIDADE DE Necromys lasiurus (RODENTIA, SIGMODONTINAE) EM ÁREAS ABERTAS DE CERRADO NO BRASIL CENTRAL  

Microsoft Academic Search

RESUMO: Investigamos comunidades de pequenos mamíferos de Cerrado em formações vegetais abertas do Parque Nacional de Emas (PNE), no Brasil Central. Amostramos 10 áreas que representavam as principais variações fisionômicas das áreas abertas do PNE. Avaliamos variações entre áreas na abundância, riqueza de espécies e densidade da espécie de pequeno mamífero mais comum na região (Necromys lasiurus). Amostramos no total

Rafael G. Becker; Gabriela Paise; Leandro C. Baumgarten; Emerson M. Vieira

248

Demography, reproductive biology and diet of the bushveld gerbil Tatera leucogaster (Rodentia: Gerbillinae) in the Lake Rukwa valley, south-western Tanzania.  

PubMed

Seasonal abundance, reproductive biology and feeding ecology of the bushveld gerbil Tatera leucogaster (Peters, 1852) were investigated in small-scale maize field-fallow land mosaics in south-western Tanzania. The gerbils were collected over a 2-year period using Sherman live and Victor hold-fast snap traps in permanent 4.5-ha grids. A total of 664 individuals were captured over 13 650 trap nights, giving an overall trap success rate of 4.9%. Trap success varied between seasons with and without crops in the field but not between habitat types. At this site, the breeding activity of this species is seasonal. All individuals whose stomachs were analyzed ate a wide range of items, indicating omnivory in this species at this site; however, seeds were the most preferred diet category, with a mean contribution of 50.4%, followed by arthropods, with a mean contribution of 25.7%. Other plant materials became important during the very dry periods. PMID:21396049

Odhiambo, Richard O; Makundi, Rhodes H; Leirs, Herwig; Verhagen, Ron

2008-03-01

249

Observations and larval descriptions of fleas (Siphonaptera: Ceratophyllidae, Ctenophthalmidae, Ishnopsyllidae) of the southern flying squirrel, little brown bat, and Brazilian free-tailed bat (Mammalia: Rodentia, Chiroptera).  

PubMed

Larvae of the four fleas infesting nests of the southern flying squirrel, Glaucomys volans colans (L.) [Conorhinopsylla stanfordi Stewart, Epitedia faceta (Rothschild), Opisodasys pseudarctomys (Baker), and Orchopeas howardi (Baker)], and of the bat fleas Myodopsylla insignis (Rothschild) and Sternopsylla distincta texana (C. Fox), associated with the bats Myotis lcifuigus (Le Conte) and Tadarida brasiliensis (I. Geof. St. Hilaire), respectively, are described. C. stanfordi has the second posterior-row seta on abdominal segments 1-5 at most one fourth the length of the first and third setae, but it is unique among the Leptopsyllini with five short setae in abdominal segment 9 anterior row. E. faceta has the straight line of anterior-row setae 2-5 on abdominal segment 1, which is diagnostic for Phalacropsyllini. O. howardi and O. pseudarctomys have three anterior-row setae on the anal comb, three ventrolateral setae on the anal segment (abdominal segment 10), and a narrow mandible with five or more teeth as other Ceratopyllinae, but O. pseudarctomys is distinguishable from O. howardi because the first setae on the posterior row of the head is long (greater than one half the length of the third posterior-row setae), the ventral setae on abdominal segment 7 are different sizes, and the third anterior-row setae on abdominal segment 8 does not extend past the spiracle posterior to it. Bat flea larvae have six posterior-row setae on abdominal segments 1-9 with the anal comb anterior row with two or more setae; M. insignis has eight mandible teeth and S. distincta texana three to four. PMID:18047188

Elbel, Robert E; Bossard, Robert L

2007-11-01

250

Ryanodine receptor binding constants in skeletal muscle, heart, brain and liver of the Mexican volcano mouse (Neotomodon alstoni alstoni; Rodentia:Cricetidae). Comparison with five other rodent species.  

PubMed

Equilibrium [3H]ryanodine binding assay was applied to total membrane fractions of six rodent species, including the Mexican volcano mouse Neotomodon alstoni alstoni, Wistar rat Rattus norvegicus albinus, golden hamster Mesocritus auratus, gerbil Meriones unguiculatus, guinea-pig Cavia porcellus, and ground squirrel Spermophillus mexicanus. The organs selected for this study were: skeletal muscle, heart, brain and liver. The constants derived from Scatchard analysis show slight variations in their Kd, ranging from 3 to 15 nM, except in the gerbil's skeletal muscle (38 nM) and the hamster's brain (27 nM). Remarkably, the Bmax calculated in guinea-pig muscle was as high as that reported for the rabbit fast twitch muscle (4.6 pmol/mg of protein) using the same membrane fraction preparation. For all the other skeletal muscles, Bmax was similar to the corresponding heart Bmax values (from 0.5 to 1 pmol/mg of protein). Gerbil cardiac Bmax was the highest (1.1 pmol/mg of protein). The ground squirrel was the rodent with more cerebral ryanodine binding sites (0.26 pmol/mg of protein), whereas the rat and the volcano mouse showed the lowest values (0.12 pmol/mg of protein). The richest sources of hepatic ryanodine receptor were the guinea-pig and rat livers (approximately equal to 0.35 pmol/mg of protein), whereas the lowest Bmax corresponded to the hamster liver (0.018 pmol/mg of protein). These results allow us to detect the similarities and differences of the ryanodine receptor binding constants from four different tissues of some of the rodents most widely used as biomedical laboratory animals. PMID:9202432

Martínez-Merlos, T; Cañedo-Merino, R; Díaz-Mu?oz, M

1997-03-01

251

Extensive mtDNA variation within the yellow-pine chipmunk, Tamias amoenus (Rodentia: Sciuridae), and phylogeographic inferences for northwest North America  

Microsoft Academic Search

The yellow-pine chipmunk, Tamias amoenus, is common in xerophytic forests throughout much of northwest North America. We analyzed cytochrome b sequence variation from 155 individuals representing 57 localities across the distribution of T. amoenus including 10 additional species of Tamias. Maximum likelihood and parsimony tree estimation methods were used in conjunction with nested clade analysis to infer both deep and

John R. Demboski; Jack Sullivan

2003-01-01

252

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

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

Valdez, Lourdes; Giorello, Facundo; Feijoo, Matías; Opazo, Juan C.; Lessa, Enrique P.; Naya, Daniel E.; D’Elía, Guillermo

2015-01-01

253

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

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. PMID:24843923

Izdebska, Joanna N; Rolbiecki, Leszek

2013-11-01

254

Demodex microti n. sp. (Acari: Demodecidae) in Microtus arvalis (Pallas) (Rodentia, Cricetidae) with a checklist of the demodecid mites of cricetids.  

PubMed

Demodex microti n. sp. (Acari, Demodecidae) is described from the skin of the genital area of the common vole Microtus arvalis (Pallas) in Poland based on the morphology of the adult and immature stages. The new species appears most similar to D. cricetuli Hurley & Desch, 1994 from the gray dwarf hamster, Cricetulus migratorius (Pallas), but differs in the following features: the supracoxal spines are conical and located at the edge of the gnathosoma, the spines of the terminal segment of palp are three, single-tined, the opisthosomal organ is narrow and elongated in males and bubble-shaped in females, the vulva is located below the incision of the fourth pair of epimeral plates, eggs are oval. The differences also relate to body size and proportions, D. microti n. sp. being smaller and slender. The new species occurred in all of the rodents examined. A checklist of demodecid mites in cricetids world-wide is also provided. PMID:24048750

Izdebska, Joanna N; Rolbiecki, Leszek

2013-10-01

255

Laboratory techniques for rearing the fleas (Siphonaptera: Ceratophyllidae and Pulicidae) of California ground squirrels (Rodentia: Sciuridae) using a novel nest box.  

PubMed

Three species of fleas, Oropsylla montana (Baker), Hoplopsyllus anomalus (Baker), and Echidnophaga gallinacea (Westwood), occur seasonally on the California ground squirrel, Spermophilus beecheyi (Richardson). Few studies have focused on the biology and ecology of these fleas despite their importance in the epidemiology of sylvatic plague. To best duplicate a natural parasite-host relationship in the laboratory, a novel nest box was developed that facilitated housing wild-caught S. beecheyi, was conducive to rearing fleas, and met modern standards for laboratory animal hygiene. This flexible system allowed adult fleas with different feeding strategies to be colonized successfully while providing sufficient flea eggs for both colony maintenance and biological research. The techniques described could be adapted to work with other species of rodents and their fleas. PMID:11372977

Metzger, M E; Rust, M K

2001-05-01

256

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

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. PMID:11931250

Metzger, Marco E; Rust, Michael K

2002-01-01

257

Similarities and differences among the chromosomes of the wild guinea pig Cavia tschudii and the domestic guinea pig Cavia porcellus (Rodentia, Caviidae)  

PubMed Central

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

Walker, Laura I.; Soto, Miguel A.; Spotorno, Ángel E.

2014-01-01

258

Proechimys (Rodentia, Echimyidae): characterization and taxonomic considerations of a form with a very low diploid number and a multiple sex chromosome system  

PubMed Central

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

2013-01-01

259

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

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. PMID:21564690

Pelz-Serrano, Karla; Munguia-Vega, Adrian; Piaggio, Antoinette J; Neubaum, Melissa; Munclinger, Pavel; Pártl, Adam; VAN Riper Iii, Charles; Culver, Melanie

2009-03-01

260

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

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.

Pelz-Serrano, K.; Munguia-Vega, A.; Piaggio, A.J.; Neubaum, M.; Munclinger, P.; PArtl, A.; van Riper, Charles, III; Culver, M.

2009-01-01

261

Coccidian parasites (Apicomplexa: Eimeriidae) of Microtus spp. (Rodentia: Arvicolidae) from the United States, Mexico, and Japan, with descriptions of five new species.  

PubMed

Beginning in July 1980, 149 voles (Microtus spp.) representing 9 species and 14 subspecies collected in Japan, Mexico and the United States were examined for coccidia; 67 (45%) had oocysts in their feces. These included 1 of 3 (33%) M. californicus sactidiegi; 0 of 1 M. longicaudus longicaudus; 0 of 1 M. l. macrurus; 48 of 111 (43%) M. mexicanus including 11 of 26 (42%) M. m. fulviventer, 1 of 2 (50%) M. m. fundatus, 13 of 31 (42%) M. m. mexicanus, 1 of 4 (25%) M. m. mogollonensis and 22 of 48 (46%) M. m. subsimus; 5 of 8 (63%) M. montanus arizonensis; 6 of 6 M. montebelli montebelli; 2 of 4 (50%) M. oregoni oregoni; 5 of 13 (38%) M. pennsylvanicus pennsylvanicus; 0 of 1 M. quasiater and 0 of 1 M. townsendii townsendii. The following coccidians were identified from infected voles: Eimeria saxei n. sp. (syn. E. wenrichi "B") from M. c. sactidiegi; E. ochrogasteri, E. saxei, E. wenrichi (syn. E. wenrichi "A"), and Eimeria sp. from M. m. fulviventer, Eimeria sp. from M. m. fundatus; E. ochrogasteri, E. saxei, Eimeria tolucadensis n. sp., E. wenrichi, and Eimeria sp. from M. m. mexicanus; E. wenrichi from M. m. mogollonensis; Eimeria coahuiliensis n. sp., E. saxei, Eimeria subsimi n. sp., E. wenrichi, Eimeria sp., and Isospora mexicanasubsimi n. sp. from M. m. subsimus; E. tamiasciuri and E. wenrichi from M. m. arizonensis; Eimeria spp. from M. m. montebelli; E. saxei and E. wenrichi from M. o. oregoni; and E. ochrogasteri and E. wenrichi from M. p. pennsylvanicus. Sporulated oocytsts of Eimeria coahuiliensis n. sp. were ellipsoid, 29.6 X 19.6 (27-34 X 18-22) micron with ovoid sporocysts 14.4 X 8.9 (13-18 X 8-10) microns. Sporulated oocysts of Eimeria saxei n. sp. were subspheroid, 13.0 X 11.0 (11-14 X 10-12) micron with ovoid sporocysts 7.5 X 4.0 (6-9 X 4-5) micron. Sporulated oocysts of Eimeria subsimi n. sp. were ovoid/subspheroid, 25.1 X 18.7 (22-28 X 17-21) micron with ellipsoid sporocysts 13.9 X 7.4 (13-15 X 6-8) micron. Sporulated oocysts of Eimeria tolucadensis n. sp. were subspheroid, 25.4 X 20.3 (23-26 X 19-23) micron with ellipsoid sporocysts 11.3 X 7.8 (10-13 X 7-9) micron. Sporulated oocysts of Isospora mexicanasubsimi n. sp. were subspheroid, 23.7 X 23.1 (21-26 X 21-26) micron with ovoid sporocysts 14.9 X 10.8 (12-16 X 10-12) micron.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:3891951

Vance, T L; Duszynski, D W

1985-06-01

262

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

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). PMID:22990827

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

2012-08-01

263

A new species of Aplodontopus (Acari: Astigmata: Chortoglyphidae) from the yellow-bellied marmot, Marmota flaviventris (Rodentia: Sciuridae) in Eastern Washington, USA, with observations on its pathology  

Microsoft Academic Search

The deutonymph of a new species of the chortoglyphid genus Aplodontopus is described from a population of Marmota flaviventris occupying a city park in eastern Washington state, USA. Many of the mite-infested individuals displayed hair loss ranging from 20–100%, along with a variety of tissue and histological abnormalities. A key to the deutonymphs of described species of Aplodontopus is presented.

Gerald W. Krantz; Barry M. OConnor; William J. Foreyt; Alex Fain

2003-01-01

264

Variation in progesterone receptors and GnRH expression in the hypothalamus of the pregnant South American plains vizcacha, Lagostomus maximus (Mammalia, Rodentia).  

PubMed

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. PMID:24089203

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

265

Variation in the helminth community structure of Thrichomys pachyurus (Rodentia: Echimyidae) in two sub-regions of the Brazilian Pantanal: the effects of land use and seasonality.  

PubMed

The Pantanal is a large ecosystem located in South America. This preserved area is seasonally flooded due to abundant rainfall during the summer and the subsequent overflow of the Paraguai River. In this paper, we examine the helminth community structure in the wild rodent Thrichomys pachyurus during the wet and dry seasons in two locations of the preserved and cattle ranching areas in the Southern Pantanal. We identified 12 species of helminth, and, although we did not find any differences in species richness between locations within the Pantanal, we found that richness was higher during the wet season. Helminth species were largely aggregated in both farm locations and during seasons. The most common helminth species were more abundant during the dry season than during the wet season, which may have been due to the increased habitat availability and rodent population increase. The intensity of the infection also followed the same pattern for most helminths. The trichostrongylids (Heligmostrongylus crucifer, H. almeidai and Pudica cercomysi) were dominant at both farm locations. The land use of each area was not correlated with helminth diversity. However, species composition of the helminth community of T. pachyurus differed between locations and may be correlated with environmental differences between the habitats. The seasonality of the Pantanal was highly correlated with helminth parasitism in T. pachyurus. PMID:19849884

Simões, R; Gentile, R; Rademaker, V; D'Andrea, P; Herrera, H; Freitas, T; Lanfredi, R; Maldonado, A

2010-09-01

266

Extensive mtDNA variation within the yellow-pine chipmunk, Tamias amoenus (Rodentia: Sciuridae), and phylogeographic inferences for northwest North America.  

PubMed

The yellow-pine chipmunk, Tamias amoenus, is common in xerophytic forests throughout much of northwest North America. We analyzed cytochrome b sequence variation from 155 individuals representing 57 localities across the distribution of T. amoenus including 10 additional species of Tamias. Maximum likelihood and parsimony tree estimation methods were used in conjunction with nested clade analysis to infer both deep and population-level processes. Our results indicate that two currently recognized subspecies of T. amoenus (T. a. canicaudus and T. a. cratericus) are not nested within other samples of T. amoenus. Maximum uncorrected levels of intraspecific sequence divergence within remaining samples of T. amoenus are >7%. Substantial geographic variation is characterized by 12 well-supported clades that correspond to distinct mountain ranges, but do not necessarily follow existing subspecific taxonomy. Significant association between geography and genealogy was detected within many of these clades and can be attributed to different population-level processes including past fragmentation, recent range expansion, and isolation by distance. PMID:12644399

Demboski, John R; Sullivan, Jack

2003-03-01

267

Karyology of the Savi pine vole, Microtus savii (De Sélys-Longchamps, 1838) (Rodentia, Arvicolidae): G-, C-, DA/DAPI-, and AluI-bands.  

PubMed

Specimens of the Savi pine vole (Microtus savii) were collected from three localities in central (Pisa and Viterbo) and southern Italy (Rosarno, Calabria) and were karyotyped using G-, C-, DA/DAPI-, and AluI-banding. All karyotypes had 2n = 54 chromosomes and seemingly identical autosomal banding. The sex chromosomes of the southern Italian specimens, M. savii brachycercus, showed additional large blocks of heterochromatin. In the northern specimens, M. savii savii, the X chromosome is metacentric, whereas in the southern specimens of M. savii brachycercus the X chromosome is a much larger submetacentric chromosome, and the Y chromosome is more than twice the size of the Y in the northern specimens. DA/DAPI staining reveals three levels of fluorescent intensity in the sex chromosomes of the Calabrian specimens. The sex chromosomes of M. savii brachycercus also have the only AluI bands seen in either chromosome set. These data suggest a heterogeneous origin and composition of the C-band regions of these chromosomes. Preliminary data suggest that fertility is reduced in crosses between the two karyomorphs. PMID:1544327

Galleni, L; Stanyon, R; Tellini, A; Giordano, G; Santini, L

1992-01-01

268

[High-resolution GTG-banding and nucleolar organizer regions of chromosomes of two vole species: Microtus rossiaemeridonionalis and M. transcaspicus (Rodentia, Arvicolidae)].  

PubMed

With the use of the GTG-banding of prometaphase chromosomes, 503 and 402 segments were revealed in haploid chromosome sets of voles Microtus rossiaemeridionalis and M. transcaspicus, respectively. Based on a detailed study of chromosomes at different condensation levels, idiograms of M. rossiaemeridionalis and M. transcaspicus chromosomes were constructed. Sequential Ag-staining and GTG-banding allowed nucleolar organizer regions (NORs) to be localized in 16 and 11 chromosome pairs of M. rossiaemeridionalis and M. transcaspicus, respectively. PMID:9777354

Mazurok, N A; Rubtsova, N V; Isaenko, A A; Nesterova, T B; Me?er, M N; Zakiian, S M

1998-08-01

269

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

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. PMID:19936950

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

2009-01-01

270

[Gene-geographical variation and genetic differentiation in red-backed voles of the genus Clethrionomys (Rodentia, Cricetidae) in the Okhotskii region].  

PubMed

Thirteen enzyme systems and three nonenzyme proteins were electrophoretically analyzed in red-backed voles of the genus Clethrionomys. In total, 25 loci were interpreted. Gene-geographic variation was studied and indices of genetic variability and differentiation were determined. By the distribution of electrophoretic variants of hemoglobin, C. rutilus was shown to be divided into two geographical groups (northern and southern). A low level of genetic differentiation was revealed in the island isolates of C. rutilus and C. rufocanus. Separation of C. rufocanus, C. rex, and C. sicotanensis into a superspecies complex was confirmed. A study of differential G- and C-banding on C. rutilus and C. rufocanus chromosomes did not reveal intraspecific variation of autosomes. In these species, karyotypes of voles from Kamchatka Peninsula were studied for the first time. They appeared to be morphologically similar to the karyotypes continental voles by both autosomes and sex chromosomes. PMID:12068550

Frisman, L V; Kartavtseva, I V; Pavlenko, M V; Kostenko, V A; Suzuki, Hitoshi; Ivasa, Masahiro; Nakata, Keisuke; Cherniavski?, F B

2002-05-01

271

A comparative analysis of the mole vole sibling species Ellobius tancrei and E. talpinus (Cricetidae, Rodentia) through chromosome painting and examination of synaptonemal complex structures in hybrids.  

PubMed

A comparative genomic analysis was carried out in the mole vole sibling species Ellobius tancrei and E. talpinus. Performing fluorescent in situ hybridisation (Zoo-FISH) using chromosome paints from the field vole Microtus agrestis showed no differences in the allocation of syntenic groups in the karyotypes of these sibling species. The only difference between their karyotypes was the position of the centromere in one pair of chromosomes, which is assumed to be the result of an inversion. To verify this hypothesis, we analysed chromosome synapsis in prophase I of meiosis. We utilised a synaptonemal complex (SC) surface-spreading technique to visualise the process of chromosome synapsis in the spermatocytes and oocytes of first-generation hybrids and back-crosses of these sibling species. In prophase I of meiosis, immunocytochemical and electron microscopy analyses revealed that all bivalents had been fully adjusted. Even in the case of a submetacentric-acrocentric bivalent with different centromere locations, synapsis of SC lateral elements was fulfilled along the entire length of the chromosomes and the formation of an inversion loop was not observed. We hypothesise that a possible mechanism leading to the change in centromere position is the repositioning and/or generation of a neocentromere. Despite the great similarity in the karyotypes of these sibling species, they exhibited significant genomic diversification, which manifested as hybrid sterility and parous female death. PMID:22343488

Bakloushinskaya, I Yu; Matveevsky, S N; Romanenko, S A; Serdukova, N A; Kolomiets, O L; Spangenberg, V E; Lyapunova, E A; Graphodatsky, A S

2012-01-01

272

An X1X1X2X2/X1X2Y mechanism of sex determination in a South American rodent, Deltamys kempi (Rodentia, Cricetidae).  

PubMed

Chromosome studies on 14 specimens of Deltamys kempi disclosed six males with 2n = 37, NF = 38, six females with 2n = 38, NF = 38, and two females with 2n = 37, NF = 38. G- and C-band analyses revealed a Y-autosome translocation in the males leading to a multiple chromosome system of sex determination of the type X1X1X2X2/X1X2Y, this being the second case of such a mechanism described in rodents. At meiosis the males presented a trivalent in which C-banding studies showed an alternate orientation of the sex chromosomes due to end-to-end association of the X1 and Y chromosomes, the Y and the X2 being held together by interstitial chiasmata. At metaphase II both n = 17 + Y and n = 18 + X1 are regularly observed. The two females with 2n = 37, NF = 38, are heterozygous for an autosomal centric fusion involving chromosomes 1 and 13. The product of the Y-autosome translocation constitutes the largest element of the karyotype (9.4% of the haploid set); the X1 chromosome amounts to 7.8% of this set, including a large heterochromatic block. When only its euchromatic region is considered, this percentage decreases to 4.6%. From two to seven NORs were observed at the telomeres, with a mean of 4.4 +/- 1.1 per cell. PMID:6368138

Sbalqueiro, I J; Mattevi, M S; Oliveira, L F

1984-01-01

273

Microtus oeconomus (Rodentia), a useful mammal for studying the induction of sex-chromosome nondisjunction and diploid gametes in male germ cells.  

PubMed Central

Preliminary data indicate that chemicals can also increase the frequency of sex-chromosome nondisjunction. Positive results--which certainly need further confirmation--have been obtained for MMS, p-fluorophenylalanine, vincristine, procarbazine, carbendazim, and bleomycin. Nocodazole, benomyl, colcemic, 6-mercaptopurine, and halothane were all negative at the concentrations tested. For the induction of diploid spermatids positive results were only obtained for MMS and parafluorophenylalanine. In view of the results obtained, the Microtus system is considered a very useful tool for analyzing factors contributing to the high frequency of aneuploidy and triploidy among abortuses and of aneuploidy in liveborn infants of men. A method is described for the detection of sex-chromosome nondisjunction and diploid spermatids in male germ cells of the field vole Microtus oeconomus. The method is based on the unique distribution pattern of heterochromatin in Microtus cells, which makes it possible to identify X and Y chromosomes in early spermatids with a simple C-banding procedure. Slide preparation is easy. Scoring of early spermatids for extra sex-chromosomes is simple and 2000-4000 cells per hour can be examined. With the Microtus system it has now been demonstrated that radiation of spermatocyte stages with doses of 50, 100 and 200 R results in a higher frequency of sex chromosome nondisjunction and of diploid gametes. Both types of aberrant gametes can be produced during the first and second meiotic division. Images FIGURE 1. FIGURE 2. FIGURE 3. FIGURE 4. PMID:387396

Tates, A D

1979-01-01

274

New karyotypes of two related species of Oligoryzomys genus (Cricetidae, Rodentia) involving centric fusion with loss of NORs and distribution of telomeric (TTAGGG)n sequences.  

PubMed

Comparative cytogenetics studies based on conventional staining, CBG, GTG, RBG-banding, Ag-NOR staining, fluorescence in situ hybridization (FISH) using telomere probes, length measurements, and meiotic data were performed on two related but previously undescribed cricetid species referred to as Oligoryzomys sp. 1 and Oligoryzomys sp. 2, respectively, from Pico das Almas (Bahia: Brazil) and Serra do Cipó (Minas Gerais: Brazil). Oligoryzomys sp. 1 had 2n = 46 and Oligoryzomys sp. 2 had 2n = 44, 44/45. Our banding data and measurements as well as FISH results support the hypothesis that the difference between the diploid numbers occurred by centric fusion events. The karyotypes had conspicuous and distinguishable macro- and micro-chromosomes, and we suppose that the largest pairs (1, 2, and 3) have evolved from a higher diploid number because of successive tandem fusion mechanisms. PMID:9474904

Silva, M J; Yonenaga-Yassuda, Y

1997-01-01

275

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

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. PMID:17497247

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

276

Microtus oeconomus (Rodentia), a useful mammal for studying the induction of sex-chromosome nondisjunction and diploid gametes in male germ cells.  

PubMed

Preliminary data indicate that chemicals can also increase the frequency of sex-chromosome nondisjunction. Positive results--which certainly need further confirmation--have been obtained for MMS, p-fluorophenylalanine, vincristine, procarbazine, carbendazim, and bleomycin. Nocodazole, benomyl, colcemic, 6-mercaptopurine, and halothane were all negative at the concentrations tested. For the induction of diploid spermatids positive results were only obtained for MMS and parafluorophenylalanine. In view of the results obtained, the Microtus system is considered a very useful tool for analyzing factors contributing to the high frequency of aneuploidy and triploidy among abortuses and of aneuploidy in liveborn infants of men. A method is described for the detection of sex-chromosome nondisjunction and diploid spermatids in male germ cells of the field vole Microtus oeconomus. The method is based on the unique distribution pattern of heterochromatin in Microtus cells, which makes it possible to identify X and Y chromosomes in early spermatids with a simple C-banding procedure. Slide preparation is easy. Scoring of early spermatids for extra sex-chromosomes is simple and 2000-4000 cells per hour can be examined. With the Microtus system it has now been demonstrated that radiation of spermatocyte stages with doses of 50, 100 and 200 R results in a higher frequency of sex chromosome nondisjunction and of diploid gametes. Both types of aberrant gametes can be produced during the first and second meiotic division. PMID:387396

Tates, A D

1979-08-01

277

Karyotypes and systematics of Asian high-mountain voles, genus Alticola (Rodentia, Arvicolidae). Results of Mongolian-German biological expeditions since 1962, No. 211.  

PubMed

Six species/subspecies of Asian high-mountain voles, genus Alticola, were studied cytogenetically via conventional staining and C- and G-banding. The karyotypes are very similar. The standard karyotype, as in A. strelzovi strelzovi, consists of 56 chromosomes. These are split into 25 acrocentric pairs, one large subtelocentric pair, one small metacentric pair, a large acrocentric X chromosome, and a small Y chromosome, which varies in shape. Constitutive heterochromatin is almost entirely restricted to small centromeric regions. A small submetacentric pair of autosomes in both subspecies of A. semicanus and a medium-sized Y chromosome in A. argentatus severtzovi are of importance in systematics. The data suggest that A. barakshin, A. semicanus, and A. argentatus are separate species. PMID:1544331

Hielscher, K; Stubbe, A; Zernahle, K; Samjaa, R

1992-01-01

278

Comparative chromosome mapping of the rRNA genes and telomeric repeats in three Italian pine voles of the Microtus savii s.l. complex (Rodentia, Cricetidae)  

PubMed Central

Abstract The Microtus (Terricola) savii s. l. complex is a group of five species/subspecies of the Italian pine voles, which diverged at different times either with or without chromosomal differentiation. The evidence of chromosomal diversification has so far concerned the shape of the sex chromosomes, especially the X chromosome. Three taxa of the group, Microtus savii savii, Microtus savii nebrodensis, and Microtus savii tolfetanus have identical karyotypes with metacentric X chromosomes. The X chromosomes of Microtus brachycercus and Microtus brachycercus niethammericus are, respectively, subtelocentric and acrocentric in shape. The Microtus savii complex has been long an object of conventional karyological studies, but comparative molecular cytogenetic data were completely missing. Therefore, we conducted a comparative chromosomal mapping of rRNA genes (rDNA) and telomeric repeats in three of the five taxa of the group: Microtus savii savii, Microtus savii nebrodensis, and Microtus brachycercus niethammericus, each of which belongs to a distinct mitochondrial clade.The survey revealed that differentiation of the clades was accompanied by remarkable changes with regard to the number and locations of the rDNA sites. Thus, Microtus savii savii and Microtus savii nebrodensis have especially high numbers of rDNA sites, which are located in the centromeric regions of, correspondingly, 18 and 13 chromosome pairs, whereas Microtus brachycercus niethammericus shows variable (8–10) and heteromorphic rDNA sites on both centromeric and telomeric regions. Interstitial telomeric sites (ITS), which are believed to indicate possible breakpoints of recurring chromosomal rearrangements, are present on the largest biarmed chromosomes and on the metacentric X chromosomes in Microtus savii savii and Microtus savii nebrodensis. These preliminary results are discussed in the context of recent advances in phylogeny of the group, as well as the rDNA genomic organization and X chromosome rearrangements in the genus Microtus. PMID:24260633

Gornung, Ekaterina; Bezerra, Alexandra M. R.; Castiglia, Riccardo

2011-01-01

279

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  

Microsoft Academic Search

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

Isa-Rita M Russo; Christian T Chimimba; Paulette Bloomer

2010-01-01

280

[Home range, use of habitat and daily activity of the gopher Orthogeomys heterodus (Rodentia: Geomyidae) in a Costa Rican horticultural area].  

PubMed

Home range, daily activity and habitat use of four Giant Pocket Gophers Orthogeomys heterodus were determined by radiotelemetry. The study was carried out in a horticultural area of Cartago province, Costa Rica, during December 1989 and January 1990. Home range averaged 325 m2 for males and 233 m2 for females. There was a significant relationship between home range size and individual body mass. In average, 78% of localizations were in the nest or refuge located in all cases in the border of crops. Activity was greatest from 0600 to 0800 h and 1200 to 1400 h, and was reduced at night. PMID:7480938

Bonino, N

1994-01-01

281

Early development of marine catfishes (Ariidae): from mouth brooding to the release of juveniles in nursery habitats.  

PubMed

The development and allometric growth patterns of the ariid catfishes Cathorops spixii and Cathorops agassizii were studied from neurula embryos to juveniles. The ontogenetic sequence revealed that prior to hatching, embryos of both species are well developed, and their axial and appendicular skeletons are well ossified. Embryos of both species grow slowly longitudinally, but positively allometric growth (growth coefficient, ?1 > 1) was observed in head width and eye diameter. It is hypothesized that these growth patterns might be related to functional priorities for the development of sensory organs, such as the inner ears (otoliths), the Weberian apparatus, eyes and nostrils, during the embryonic period. The first appearance of vertebrae and otoliths, as well as the ossification of otoliths and the Weberian apparatus, occur earlier in embryos of C. agassizii than in embryos of C. spixii. After hatching, mouth-brooded free embryos of both species grow isometrically. Negatively allometric growth was observed in head width and eye diameter during the yolk-sac period, which is expected given that the sensory organs are already formed. Free embryos of C. agassizii are distinguishable from those of C. spixii by their larger eyes, longer snouts, longer heads and heavier yolk sacs. The end of the yolk-sac period is characterized by a direct change from free embryo to juvenile, without a true larval period. The juveniles of the two species can also be distinguished from each other by the larger eyes of C. agassizii compared with C. spixii, as in adult fishes. PMID:23731148

Lima, A R A; Barletta, M; Dantas, D V; Ramos, J A A; Costa, M F

2013-06-01

282

Phylogeny and chronology of the major lineages of New World hystricognath rodents: insights on the biogeography of the Eocene/Oligocene arrival of mammals in South America  

PubMed Central

Background The hystricognath rodents of the New World, the Caviomorpha, are a diverse lineage with a long evolutionary history, and their representation in South American fossil record begins with their occurrence in Eocene deposits from Peru. Debates regarding the origin and diversification of this group represent longstanding issues in mammalian evolution because early hystricognaths, as well as Platyrrhini primates, appeared when South American was an isolated landmass, which raised the possibility of a synchronous arrival of these mammalian groups. Thus, an immediate biogeographic problem is posed by the study of caviomorph origins. This problem has motivated the analysis of hystricognath evolution with molecular dating techniques that relied essentially on nuclear data. However, questions remain about the phylogeny and chronology of the major caviomorph lineages. To enhance the understanding of the evolution of the Hystricognathi in the New World, we sequenced new mitochondrial genomes of caviomorphs and performed a combined analysis with nuclear genes. Results Our analysis supports the existence of two major caviomorph lineages: the (Chinchilloidea?+?Octodontoidea) and the (Cavioidea?+?Erethizontoidea), which diverged in the late Eocene. The Caviomorpha/phiomorph divergence also occurred at approximately 43 Ma. We inferred that all family-level divergences of New World hystricognaths occurred in the early Miocene. Conclusion The molecular estimates presented in this study, inferred from the combined analysis of mitochondrial genomes and nuclear data, are in complete agreement with the recently proposed paleontological scenario of Caviomorpha evolution. A comparison with recent studies on New World primate diversification indicate that although the hypothesis that both lineages arrived synchronously in the Neotropics cannot be discarded, the times elapsed since the most recent common ancestor of the extant representatives of both groups are different. PMID:23607317

2013-01-01

283

Molecular Ecology Notes (2006) 6, 3640 doi: 10.1111/j.1471-8286.2005.01128.x 2006 Blackwell Publishing Ltd  

E-print Network

) and deer mouse (Peromyscus maniculatus) for studies of conservation, ecological, quantitative of genomic resources for Peromyscus, an emerging model system for ecological and evolutionary research. Keywords: deer mouse, microsatellites, oldfield mouse, Peromyscus, Rodentia, simple sequence repeats

Hoekstra, Hopi E.

284

Hoplopleura janzeni n. sp. (Phthiraptera: Anoplura), a new sucking louse from a Central American swimming mouse  

E-print Network

Both sexes of a new species of sucking louse Hoplopleura janzeni (Phthiraptera: Hoplopleuridae) are described and illustrated from the Central American ichthyomyine swimming mouse Rheomys raptor (Rodentia: Muridae) collected ...

Durden, Lance A.; Timm, Robert M.

2001-12-01

285

Movement patterns of catfishes (Ariidae) in a tropical semi-arid estuary.  

PubMed

From December 2005 to November 2006, 216 samples were taken from the main channel of the Goiana Estuary, representing a total sampled area of 23 ha. Ariidae species were the most abundant in density (1600 individuals ha(-1), 53%) and biomass (18,813 g ha(-1), 63%). Cathorops spixii was the most abundant in density (1340 individuals ha(-1)) and biomass (14,203 g ha(-1)). The variables: number of species, total density and biomass, showed significant interactions between the factors of areas and seasons (P < 0.01). The highest total density (7394 individuals ha(-1)) and biomass (70,292 g ha(-1)) occurred in the middle and upper estuaries, respectively, during the early-rainy season. The density of C. spixii differed significantly between areas and seasons (P < 0.01), while Cathorops agassizii differed significantly only between seasons (P < 0.01). The biomass differed significantly for the species C. spixii, C. agassizii and Sciades herzbergii between seasons, and C. spixii and C. agassizii between areas. Also, the density and biomass of C. spixii and C. agassizii showed interaction between areas and seasons. Only the biomass of S. herzbergii showed interaction between areas and seasons (P < 0.01). This indicates that seasonal variations influenced the distribution of Ariidae species in the different areas of the Goiana Estuary. Moreover, canonical correspondence analysis highlighted a strongly significant correlation (P < 0.01) between the seasonal variations of the environmental gradients (salinity and water temperature) and distribution of catfishes. The management and conservation of estuaries should take into account the life cycle of these species in different estuarine areas and hydrological seasons. PMID:20557607

Dantas, D V; Barletta, M; Costa, M F; Barbosa-Cintra, S C T; Possatto, F E; Ramos, J A A; Lima, A R A; Saint-Paul, U

2010-06-01

286

Testing Synchrony in Historical Biogeography: The Case of New World Primates and Hystricognathi Rodents  

PubMed Central

The abrupt appearance of primates and hystricognath rodents in early Oligocene deposits of South America has puzzled mastozoologists for decades. Based on the geoclimatic changes that occurred during the Eocene/Oligocene transition period that may have favoured their dispersal, researchers have proposed the hypothesis that these groups arrived in synchrony. Nevertheless, the hypothesis of synchronous origins of platyrrhine and caviomorph in South America has not been explicitly evaluated. Our aim in this work was to apply a formal test for synchronous divergence times to the Platyrrhini and Caviomorpha splits. We have examined a previous work on platyrrhine and hystricognath origins, applied the test to a case where synchrony is known to occur and conducted simulations to show that it is possible to formally test the age of synchronous nodes. We show that the absolute ages of Platyrrhini/Catarrhini and Caviomorpha/Phiomorpha splits depend on data partitioning and that the test applied consistently detected synchronous events when they were known to have happened. The hypothesis that the arrival of primates and hystricognaths to the New World consisted of a unique event cannot be rejected PMID:22346342

Loss-Oliveira, Leticia; Aguiar, Barbara O.; Schrago, Carlos G.

2012-01-01

287

Description of a new species of Heligmonina Baylis, 1928 (Nematoda: Heligmonellidae) a parasite of Mastomys natalensis (Rodentia: Muridae) from Swaziland and new data on the synlophe of Heligmonina chabaudi (Desset, 1966).  

PubMed

A new species of heligmosomoid nematode belonging to the subfamily Nippostrongylinae Durette-Desset, 1970 is described: Heligmonina wakelini n. sp., a parasite from the small intestine of the commensal rodent Mastomys natalensis (Smith, 1834) from Swaziland. It differs from the most closely related species H. boomkeri Durette-Desset & Digiani, 2005 by the number of the cuticular ridges in the female synlophe (10 vs 12), the width of the left ala, larger than the body diameter in the male, and the inclination of the axis of orientation of the ridges in both sexes (53 degrees vs 70 degrees). New morphological data (head and synlophe) on Heligmonina chabaudi (Desset, 1964), also a parasite of Mastomys natalensis in the Republic of Congo, are provided in order to compare with the new species. PMID:18225415

Duretre-Desset, M C; Digiani, M C; Mahlaba, T; Behnke, J M

2007-12-01

288

[Leishmania major Yakimoff et Schokhor, 1914 (Kinetoplastida: Trypanosomatidae) in Meriones shawi Duvernoy, 1842 (Rodentia: Gerbillidae): persistence of the infection in meriones and its infectivity for the sand fly vector (Phlebotomus) papatasi Scopoli, 1786 (Diptera: Psychodidae)].  

PubMed

The ability of the sand fly Phlebotomus papatasi to transmit Leishmania major, the etiologic agent of zoonotic cutaneous leishmaniasis, to Meriones shawi, the natural reservoir host of this parasite, was studied under laboratory conditions. Sand flies became infected with L. major after feeding on a lesion of needle-inoculated M. shawi. Moreover, P. papatasi, previously infected with L. major, transmitted the parasite to M. shawi by bite during a second bloodmeal. Two months after the blood-meal, the animal developed a lesion on its ears. Xenodiagnosis was performed on the infected animal. The infectivity of M. shawi to P. papatasi lasted for five months, period corresponding to winter season in North Africa. We have thus demonstrated the transmission of L. major by P. papatasi to M. shawi under laboratory conditions. Our results show that reservoir hosts surviving winter time are the main source of infection for P. papatasi during the following season, and subsequently they play a major role in the persistence and transmission of L. major between transmission cycles. PMID:23055379

Derbali, M; Chelbi, I; Ben Hadj Ahmed, S; Zhioua, E

2012-12-01

289

Coccidia of Brazilian mammals: Eimeria corticulata n. sp. (Apicomplexa: Eimeriidae) from the anteater Tamandua tetradactyla (Xenarthra: Myrmecophagidae) and Eimeria zygodontomyis n. sp. from the cane mouse Zygodontomys lasiurus (Rodentia: Cricetidae).  

PubMed

Feces from a specimen of Tamandua tetradactyla (Linn.) from Portel, Pará State, north Brazil, contained two different coccidial oocysts; one identified as Eimeria tamanduae Lainson 1968, and the other as a new species, described here as Eimeria corticulata n. sp. Oocysts of E. corticulata are ellipsoidal, 37.4 x 30.4 (31.2-43.7 x 23.7-35.0) microns, shape index (length/width) 1.2 (1.0-1.5). Oocyst wall 2.5-3.7 microns thick and composed of two layers; an outer thick, brown-yellow one with radial striations, and a thin inner smooth one: no visible micropyle. Oocyst residuum a large globule of about 10.7 x 10.3 microns, usually accompanied by a number of smaller attached globules. Sporocysts ellipsoidal, 21.0 x 11.0 (20.0-22.5 x 10.0-12.5) microns, with a conspicuous Stieda body; shape index 1.9 (1.6-2.2). Sporocyst residuum a small number of scattered granules: sporozoites 18.7 x 5.0 microns, with a large posterior refractile body. Eimeria zygodontomyis n. sp. is described in feces from Zygodontomys lasiurus (Lund) from the Serra dos Carajás, Pará. Oocysts ellipsoidal to cylindrical, 16.5 x 12.0 (13.7-18.7 x 11.2-12.3) microns, shape index 1.4 (1.2-1.5). Wall colorless, smooth, single-layered and about 0.6 micron thick: no micropyle. No oocyst residuum, but a polar granule of about 1.8 x 1.0 microns is sometimes present. Sporocysts ellipsoidal, 8.4 x 5.5 (7.5-8.7 x 5.0-6.2) microns, shape index 1.5 (1.4-1.7), with a thin colorless wall and a delicate Stieda body. Sporozoites enclose a compact residuum of about 2.5 x 3.7 microns. PMID:2406431

Lainson, R; Shaw, J J

1990-01-01

290

Monophyly of the Order Rodentia Inferred from Mitochondrial DNA Sequences of the Genes for 12s rRNA, 16s rRNA, and tRNA-Valine  

E-print Network

genes) confirm that some individual genes support rodent polyphyly but that tandem analysis of all data this controversy, may have a single explanation: a cascade effect resulting from inactivation of the zinc to the insulin-cascade hypothesis. Introduction Nearly half (2,02 1) of all living mammal species are rodents

Hedges, Blair

291

Heterogeneity and meiotic behaviour of B and sex chromosomes, banding patterns and localization of (TTAGGG)n sequences by fluorescence in situ hybridization in the neotropical water rat Nectomys (Rodentia, Cricetidae).  

PubMed

A cytogenetic study using fluorescence in situ hybridization (FISH) of telomere probes, CBG, GTG and RBG banding patterns and synaptonemal complex data was carried out in 41 specimens of Nectomys from three Brazilian states: Pernambuco, Mato Grosso and São Paulo. The specimens presented 2n = 52, 53, 56 and 57, and the differences in chromosome number were due to the presence of three different supernumeraries and also to the occurrence of tandem fusions. The tandem fusions involved chromosome pairs 3 + 11 and 5 + 24 from karyotype with 2n = 56 that originated pairs 1 and 4 in specimens with 2n = 52. Sex chromosome polymorphism was also detected, and the X presented three different morphologies, which could be explained by heterochromatin addition/deletion. FISH results revealed interstitial telomeric bands (ITBs) in a submetacentric B, but no ITB was detected in the chromosomes originated by tandem fusion. The supernumeraries presented a remarkable heterogeneity of size and morphology, constitutive heterochromatin pattern and localization of telomeric sequences. Synaptonemal complex by light and electron microscopy showed the supernumerary as an autopaired univalent. The sex chromosome pairing in meiotic cells involved the heterochromatic short arm of the X chromosome and the short arm of the Y chromosome. PMID:9865784

de Jesus Silva, M J; Yonenaga-Yassuda, Y

1998-09-01

292

Arsenic and other trace elements in two catfish species from Paranaguá Estuarine Complex, Paraná, Brazil.  

PubMed

Concentrations of arsenic and four additional trace elements (Cu, Cr, Ni, and Zn) were determined by inductively coupled plasma-optical emission spectrometry in the muscular tissue of the yellow catfish (Cathorops spixii) and the urutu catfish (Genidens genidens) from Paranaguá Estuarine Complex, Brazil (PEC). The PEC can be characterized by an environment of high ecological and economic importance in which preserved areas of rainforest and mangroves coexist with urban activities as ports and industries. The average concentrations (in milligram per kilogram dry weight) of elements in the muscle tissue of C. spixii are as follows: Zn (31), As (17), Cu (1.17), Cr (0.62), and Ni (0.28). Similar concentrations could be found in G. genidens with exception of As: Zn (36), As (4.78), Cu (1.14), Cr (0.51), and Ni (0.14). Fish from the geographic northern rural region (Guaraqueçaba-Benito) display higher As concentrations in the muscle tissues than fish found in the south-western (urban) part of the PEC. An international comparison of muscle tissue concentrations of trace elements in fish was made. Except for Ni in C. spixii, a tendency of decrease in element concentration with increasing size (age) of the fish could be observed. According to the National Health Surveillance Agency of Brazil, levels of Cr and As exceeded the permissible limits for seafood. An estimation of the provisional tolerable weekly intake of As was calculated with 109 % for C. spixii and with 29 % for G. genidens. PMID:23584825

Angeli, J L F; Trevizani, T H; Ribeiro, A; Machado, E C; Figueira, R C L; Markert, B; Fraenzle, S; Wuenschmann, S

2013-10-01

293

INVASIVE RODENTS ON ISLANDS Direct and indirect effects of rats: does rat eradication  

E-print Network

. rattus, R. norvegicus and R. exulans) have been eradicated from islands has greatly accelerated Springer Science+Business Media B.V. 2008 Abstract Introduced rats (Rattus spp.) can affect island Á Woody seedlings Introduction Humans have introduced rats (Rattus spp.; Rodentia: Muridae

Fukami, Tadashi

294

2002 Blackwell Science Ltd. http://www.blackwell-science.com/geb RESEARCH ARTICLE  

E-print Network

& Biogeography (2002) 11, 131­141 Blackwell Science Ltd Geographical distributions of spiny pocket mice in South geographical distributions of two spiny pocket mice (Rodentia: Heteromyidae) in north- western South America of Heteromys australis and H. anomalus to produce the models. Results GARP models indicate the potential

Anderson, Robert P.

295

SMALL MAMMALS COLLECTED IN THE UDZUNGWA MOUNTAINS NATIONAL PARK, TANZANIA  

Microsoft Academic Search

Small mammals were sampled in the Udzungwa Mountains National Park, Tanzania, during 1995 and 1996. Twenty-four species, representing 16 genera were recorded for three orders: Insectivora, Chiroptera and Rodentia. Identifications and natural history information are presented for this poorly known fauna from a unique Eastern Arc Mountains habitat.

William T. Stanley; Alfeo M. Nikundiwe; Fatina A. Mturi; Philip M. Kihaule; Patricia D. Moehlman

2005-01-01

296

Vilnius City Theriofauna  

Microsoft Academic Search

Mammal diversity investigations in Vilnius were carried out in 1992, 1998–2004. The following 51 mammal species were registered in the city: five species of insectivores (Insectivora), 11 of bats (Chiroptera), 18 of rodents (Rodentia), two of hares (Lagomorpha), 11 of carnivores (Carnivora) and four of ungulates (Artiodactyla). Fourteen mammal species are included into the Red Data Book of Lithuania, namely

Kazimieras Baranauskas; Linas Bal?iauskas; Reda Mažeikyt?

2005-01-01

297

Multiple Paternity in Belding's Ground Squirrel Litters  

Microsoft Academic Search

Sexually receptive female Spermophilus beldingi (Rodentia: Sciuridae) usually mate with several different males. The paternity of 27 litters born in 1977 and 1978 was ascertained by combining field observations of mating with laboratory paternity exclusion analyses. Most of the litters (78 percent) were multiply sired, usually by two or three males. This may be the highest frequency of multiple paternity

James Hanken; Paul W. Sherman

1981-01-01

298

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....

299

Evidence for rodent-common and species-typical limb and digit use in eating, derived from a comparative analysis of ten rodent species  

Microsoft Academic Search

Order Rodentia comprises a vast portion of mammalian species (1814 species), which occupy extremely diverse habitats requiring very distinct motor specializations (e.g. burrowing, hopping, climbing, flying and swimming). Although early classification of paw use ability suggests rodents are impoverished relative to primates and make little use of their paws, there have been no systematic investigations of paw use in rodents.

I. Q. Whishaw; J. R. Sarna; S. M. Pellis

1998-01-01

300

FoliaZnl. -41(4):241-247(1998) New evidenceof pseudosexualbehaviour and female aggressionin  

E-print Network

9 6 ,F r y n t a & C i h 6 k o v a 1 9 9 6 ) .T h e r e f o r e ,w e perforntcddyadic encountersin: neutral cageinteractions in Mus spicilegusand Mus spretus (Rodentia:Muridae) EvaSUCHOMELOVA.PavclIV{UNCLINGERandDaniel

Frynta, Daniel

301

Extinction of the autochthonous small mammals of Mallorca (Gymnesic Islands,  

E-print Network

ORIGINAL ARTICLE Extinction of the autochthonous small mammals of Mallorca (Gymnesic Islands-mail: vieapba@uib.es Abstract Aim To investigate the chronology, causes and consequences of the extinction of two extinct endemic small mammals from Mallorca: the Balearic dormouse, Eliomys morpheus (Rodentia

Binford, Michael W.

302

273:278-286, 1997.Am J Physiol Regul Integr Comp Physiol T. M. Lee and S. E. Labyak  

E-print Network

secretion Daytime naps in darkness phase shift the human circadian rhythms of melatonin [Full Text on this article's topics Physiology .. Chronobiology Physiology .. Rodentia Physiology .. Mammalia can be found at:Integrative and Comparative Physiology American Journal of Physiology - Regulatory,aboutAdditional material and information

Lee, Theresa

303

Un exemple de corrélation marin continental dans le Priabonien de Roumanie. Remarques sur la Grande CoupureAn example of marine continental correlation in the Priabonian of Romania. Comments on the 'Grande Coupure' event  

NASA Astrophysics Data System (ADS)

Between the Calata and Turea marine series, some Priabonian continental intercalations with charophytes and mammals were found. The presence of Cricetids (Rodentia, Muroidea), one of the migrants representative of the Grande Coupure event, lead to the conclusion that in this region, like in Southern Germany, the migration of the Asian elements is earlier than in western Europe.

Baciu, Calin; Hartenberger, Jean-Louis

2001-10-01

304

MAMMALIAN SPECIES No. 641, pp. 17, 5 figs. Thomomys mazama. By B. J. Verts and Leslie N. Carraway  

E-print Network

miles south of South Yolla Bolly Mountain, altitude about 7500 feet, in Tehama County, California.'' T of the Rogue River, Curry County, Oregon.'' CONTEXT AND CONTENT. Order Rodentia, family Geo- myidae, genus, 1981): T. m. couchi Goldman, 1939:243. Type locality ``4 miles north Shelton, Mason County, Washington

Hayssen, Virginia

305

Differences in food hoarding behaviour in two species of ground squirrels Spermophilus tridecemlineatus and S. spilosoma  

Microsoft Academic Search

Storing food items is considered an alternative to fat storage in many species of ground squirrels. In a comparative study in the laboratory, we hypothesized that two closely-related ground squirrels, Spermophilus tridecemlineatus and S. spilosoma (subgenus Ictidomys, Rodentia Sciuridae), could hoard food and that the highest proportion of individuals displaying hoarding should be observed in the species with the greatest

B. Livoreil; C. Baudoin

1996-01-01

306

The prehistoric diet and subsistence of the lower Pecos region, as reflected in coprolites from Baker Cave, Val Verde County, Texas  

E-print Network

Rodentia Salerno hll s mexicanus a~as 0 s o m S. varie atus ~tom s luce icianus Ammos erma hilus i~ate res Sciurus carolinensis ~S. ni e ~ 7~human s hottae a~no s pe so atua P~ao e n s c~stano s Perp nathus merriami P, ~is i d ~ P. enicillatus P...

Sobolik, Kristin Dee

1988-01-01

307

Deterioration of the Gao Vomeronasal Pathway in Sexually Dimorphic Mammals  

E-print Network

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 Gai2-protein throughout AOB glomeruli, while Gao expression is restricted to main olfactory glomeruli

Rodrigo Suárez; Pedro Fernández-aburto; Paul R. Manger; Jorge Mpodozis

308

Individual recognition and incest avoidance in eusocial common mole-rats rather than reproductive suppression by parents  

Microsoft Academic Search

Non-reproductive females in families of eusocial common mole-rats (Cryptomys sp., Rodentia) are not suppressed by their mother, (either behaviourally or pheromonally) as is generally assumed. They do not mate with their father and brothers simply because they are not sexually attractive for them (and vice versa). The incest avoidance is based on the capability to recognize (and keep in memory

H. Burda

1995-01-01

309

Perturbation analysis of competition and overlap in habitat utilization between Dipodomys ordii and Dipodomys merriami  

Microsoft Academic Search

The populations of two coexisting species of Dipodomys (Heteromyidae, Rodentia) were manipulated on 10, large, unenclosed, trapping grids. These manipulations revealed that, although many kangaroo rats are established residents in an area, a large number are transient individuals who quickly occupy vacated habitats. On plots from which residents had been removed, transients settled at rates of up to 5% of

Gene D. Schroder; Michael L. Rosenzweig

1975-01-01

310

A stereotaxic atlas of the brain of the naked mole-rat ( Heterocephalus glaber)  

Microsoft Academic Search

The naked mole-rat (Rodentia, Bathyergidae: Heterocephalus glaber) is a strictly subterranean eusocial mammal. These rodents show a suite of morphological and physiological adaptations, including brain specializations, to this underground milieu that they have inhabited since the early Miocene. Recently, naked mole-rats have received considerable attention as the longest living rodent known, and some of these brain specializations may be potentially

J. Xiao; J. B. Levitt; R. Buffenstein

2006-01-01

311

Sex ratios in high-density populations of the montane vole, Microtus montanus , and the behavior of territorial males  

Microsoft Academic Search

Montane voles (Microtus montanus nanus, Rodentia: Muridae) were studied in unconfined populations and in an exclosure in open fields in Wyoming, USA. Field work involved capture-mark-recapture grids, tagging select individuals with irradiated wires, subcutaneous implantation of dye pellets, and behavioral observations.

Frederick J. Jannett

1981-01-01

312

Sound Localization in a Predatory Rodent, the Northern Grasshopper Mouse (Onychomys leucogaster )  

Microsoft Academic Search

A comparison of the ability of mammals to localize sound revealed that among the animals examined to date, none of the rodents have been able to localize as accurately as the carnivores. Because all of these rodents are prey animals, the question arises as to whether their poor localization acuity is a phyletic trait of Rodentia or whether it is

Rickye S. Heffner; Henry E. Heffner

1988-01-01

313

Spatial distribution of meadow jumping mice ( Zapus hudsonius) in logged boreal forest of northwestern Canada  

Microsoft Academic Search

Most studies of small mammal responses to habitat alterations focus on dominant species, with a resulting lack of information for rare species. Jumping mice (Order Rodentia: Dipodidae) tend to be rare in small mammal trapping studies; thus, little is known of their response to habitat alterations, such as clear-cut logging. We examined the spatial distribution of meadow jumping mice (Zapus

Thomas S. Jung; Todd Powell

2011-01-01

314

North American Miocene land mammals from Panama  

Microsoft Academic Search

Miocene land mammals are described from the Gaillard Cut Local Fauna based on a collection made by Stewart and Whitmore in the 1960s from Cucaracha Reach, former Canal Zone, Republic of Panama. In addition to the Order Rodentia described elsewhere, the land mammals represent three other orders (Carnivora [new record], Artiodactyla, Perissodactyla), including the canid Tomarctus brevirostris, indeterminant Amphicyonidae or

Bruce J. Macfadden

2006-01-01

315

Phylogenetic Analysis of Cystic Fibrosis Transmembrane Conductance Regulator Gene in Mammalian Species Argues for the Development of a Rabbit Model for Cystic Fibrosis  

Microsoft Academic Search

The species-specific pattern of cystic fibrosis transmembrane conductance regulator (CFTR) expression was inves- tigated in order to identify species closely related to man which can be used as potential cystic fibrosis (CF) animal models. To this purpose, the nucleotide sequences of the CFTR promoter region of eight mammalian species representing four different orders (Primates, Artiodactyla, Lagomorpha, and Rodentia) were analyzed.

Sandrine Vuillaumier; Bernhard Kaltenboeck; T Guillaume Lecointre; Pierre Lehn; Erick Denamur

316

Importance of cholinesterase kinetic parameters in environmental monitoring using estuarine fish.  

PubMed

The aim of the present study was to determine the kinetic parameters and cholinesterase (ChE) activity in two teleost fish, the white mouth croaker Micropogonias furnieri (Scianidae) and the Madamango sea catfish Cathorops spixii (Ariidae), to verify their suitability as sentinel species of aquatic pollution by anticholinergic compounds. Individuals of each species were captured in one reference and one polluted site in the Southern Brazilian coast. Brain tissue was used as enzyme source. Inhibition kinetic parameters indicated that ChE from C. spixii collected at the reference site showed more affinity (Ka) for eserine that from those collected at the polluted site. The opposite was observed for the carbamylation constants (Kc). Thus, similar inhibition constants (Ki) were observed. M. furnieri brain showed an extremely low sensitivity to in vitro inhibition by eserine, indicating that it is not a suitable biomarker to be employed in environmental monitoring of anticholinergic compounds. Results from the present study also point to the need for considering kinetic analysis when cholinesterase activity is employed as a biomarker. PMID:16643981

Tortelli, V; Colares, E P; Robaldo, R B; Nery, L E M; Pinho, G L L; Bianchini, A; Monserrat, J M

2006-10-01

317

Plastic debris ingestion by marine catfish: an unexpected fisheries impact.  

PubMed

Plastic marine debris is a pervasive type of pollution. River basins and estuaries are a source of plastics pollution for coastal waters and oceans. Estuarine fauna is therefore exposed to chronic plastic pollution. Three important catfish species [Cathorops spixii (N=60), Cathorops agassizii (N=60) and Sciades herzbergii (N=62)] from South Western Atlantic estuaries were investigated in a tropical estuary of the Brazilian Northeast in relation to their accidental ingestion of plastic marine debris. Individuals from all three species had ingested plastics. In C. spixii and C. agassizii, 18% and 33% of individuals had plastic debris in their stomachs, respectively. S. herzbergii showed 18% of individuals were contaminated. All ontogenetic phases (juveniles, sub-adults and adults) were contaminated. Nylon fragments from cables used in fishery activities (subsistence, artisanal and commercial) played a major role in this contamination. These catfish spend their entire life cycles within the estuary and are an important feeding resource for larger, economically important, species. It is not yet possible to quantify the scale and depth of the consequences of this type of pollution. However, plastics are well known threat to living resources in this and other estuaries. Conservation actions will need to from now onto take plastics pollution into consideration. PMID:21354578

Possatto, Fernanda E; Barletta, Mário; Costa, Monica F; do Sul, Juliana A Ivar; Dantas, David V

2011-05-01

318

Comparative genetics of longevity and cancer: insights from long-lived rodents  

PubMed Central

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

Gorbunova, Vera; Seluanov, Andrei; Zhang, Zhengdong; Gladyshev, Vadim N.; Vijg, Jan

2015-01-01

319

Tool use by naked mole-rats  

Microsoft Academic Search

Naked mole-rats (Heterocephalus glaber, Rodentia: Bathyergidae) excavate extensive subterranean burrows with their procumbent incisors. Captive individuals often\\u000a place a wood shaving or tuber husk behind their incisor teeth and in front of their lips and molar teeth while gnawing on\\u000a substrates that yield fine particulate debris. This oral barrier may prevent choking or aspiration of foreign material. Consistent\\u000a use of

Gabriela Shuster; Paul W. Sherman

1998-01-01

320

Social Structure Predicts Genital Morphology in African Mole-Rats  

Microsoft Academic Search

BackgroundAfrican 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

Marianne L. Seney; Diane A. Kelly; Bruce D. Goldman; Radim Sumbera; Nancy G. Forger; Anna Dornhaus

2009-01-01

321

The density-dependent formation of extended maternal families of the montane vole, Microtus montanus nanus  

Microsoft Academic Search

1.Montane voles (Microtus montanus; Rodentia: Muridae) were studied in unconfined populations and in an enclosure in open fields in Wyoming. The field work involved capture-mark-recapture grids, tagging of select individuals with irradiated wires, and behavioral observations.2.When not nesting in proximity to another parous female in the field, the M. montanus dam abandoned her brood nest and young at about 15

Frederick J. Jannett

1978-01-01

322

Energetics of hibernating yellow-bellied marmots ( Marmota flaviventris)  

Microsoft Academic Search

Yellow-bellied marmots (Rodentia: Sciuridae) typically hibernate for eight months. This study explored energetic costs of hibernation in young and adults at 10 and 6 °C. Age significantly affected the percent time torpid, total and mass-specific Vo2, use of energy during torpor, and daily mass loss at 6 °C. Thus young had a higher mass-specific Vo2 during a torpor bout, which

Kenneth B. Armitage; Daniel T. Blumstein; Brett C. Woods

2003-01-01

323

Total mercury in sediments and in Brazilian Ariidae catfish from two estuaries under different anthropogenic influence.  

PubMed

Santos-São Vicente estuary, located in São Paulo State, Brazil, has a history of contamination by inorganic chemicals such as mercury (Hg). In the 1980s the Cubatão was considered one of the most polluted sites in the world as a consequence of the intense industrial activities located in the city close to the estuary. To provide data and evaluate the local biota, total mercury (THg) contents were determined in sediments and in fish, Cathorops spixii, from different areas of the Santos-São Vicente estuary. For comparison, samples were also collected in a non-polluted system with similar hydrochemistry characteristics, the Cananeia estuary. The water characteristics and THg levels in sediment and fish samples confirmed a high human influence in the Santos-São Vicente estuary. The lowest THg values, observed in Cananeia, were evidence of low anthropogenic influence. High values observed in Santos-São Vicente show the necessity for a monitoring program. PMID:22030105

Azevedo, Juliana S; Braga, Elisabete S; Favaro, Deborah T; Perretti, Adriana R; Rezende, Carlos Eduardo; Souza, Cristina Maria M

2011-12-01

324

Diel variation in fish assemblages in tidal creeks in southern Brazil.  

PubMed

Tidal creeks are strongly influenced by tides and are therefore exposed to large differences in salinity and depth daily. Here we compare fish assemblages in tidal creeks between day and night in two tidal creeks in southern Brazil. Monthly day and night, simultaneous collections were carried out in both creeks using fyke nets. Clupeiformes tended to be caught more during the day. Cathorops spixii, Genidens genidens and Rypticus randalli tended to be caught at night. Sciaenidae also tended to be caught more during the night. In general, pelagic species were diurnal, while deep water species were nocturnal. These trends are probably due to a variety of causes, such as phylogeny, predation and net avoidance. PMID:18470376

Oliveira-Neto, J F; Spach, H l; Schwarz-Junior, R; Pichler, H A

2008-02-01

325

Domestic, peridomestic and wild hosts in the transmission of Trypanosoma cruzi in the Caatinga area colonised by Triatoma brasiliensis  

PubMed Central

The role played by different mammal species in the maintenance of Trypanosoma cruzi is not constant and varies in time and place. This study aimed to characterise the importance of domestic, wild and peridomestic hosts in the transmission of T. cruzi in Tauá, state of Ceará, Caatinga area, Brazil, with an emphasis on those environments colonised by Triatoma brasiliensis. Direct parasitological examinations were performed on insects and mammals, serologic tests were performed on household and outdoor mammals and multiplex polymerase chain reaction was used on wild mammals. Cytochrome b was used as a food source for wild insects. The serum prevalence in dogs was 38% (20/53), while in pigs it was 6% (2/34). The percentages of the most abundantly infected wild animals were as follows: Thrichomys laurentius 74% (83/112) and Kerodon rupestris 10% (11/112). Of the 749 triatomines collected in the household research, 49.3% (369/749) were positive for T. brasiliensis, while 6.8% were infected with T. cruzi (25/369). In captured animals, T. brasiliensis shares a natural environment with T. laurentius, K. rupestris, Didelphis albiventris, Monodelphis domestica, Galea spixii, Wiedomys pyrrhorhinos, Conepatus semistriatus and Mus musculus. In animals identified via their food source, T. brasiliensis shares a natural environment with G. spixii, K. rupestris, Capra hircus, Gallus gallus, Tropidurus oreadicus and Tupinambis merianae. The high prevalence of T. cruzi in household and peridomiciliar animals reinforces the narrow relationship between the enzootic cycle and humans in environments with T. brasiliensis and characterises it as ubiquitous. PMID:25410992

Bezerra, Claudia Mendonça; Cavalcanti, Luciano Pamplona de Góes; de Souza, Rita de Cássia Moreira; Barbosa, Silvia Ermelinda; Xavier, Samanta Cristina das Chagas; Jansen, Ana Maria; Ramalho, Relrison Dias; Diotaiut, Liléia

2014-01-01

326

Pro-inflammatory activities in elapid snake venoms.  

PubMed Central

1. Snake venoms from the genera Micrurus (M. ibiboboca and M. spixii) and Naja (N. naja, N. melanoleuca and N. nigricollis) were analysed, using biological and immunochemical methods, to detect pro-inflammatory activities, cobra venom factor (COF), proteolytic enzymes, thrombin-like substances, haemorrhagic and oedema-producing substances. 2. The venoms of the five snake species activate the complement system (C) in normal human serum (NHS) in a dose-related fashion, at concentrations ranging from 5 micrograms to 200 micrograms ml-1 serum. Electrophoretic conversion of C3 was observed with all venoms in NHS containing normal concentrations of Ca2+ and Mg2+, but only by venoms from N. naja and N. melanoleuca when Ca2+ was chelated by adding Mg(2+)-EGTA. 3. Purified human C3 was electrophoretically converted, in the absence of other C components, by the venoms from N. naja, N. nigricollis and M. ibiboboca. However, only the venoms from N. naja and N. melanoleuca contained a 144 kDa protein revealed in Western blot with sera against COF or human C3. 4. All venoms, at minimum concentrations of 30 ng ml-1, were capable of lysing sheep red blood cells, also in a dose-related fashion, when incubated with these cells in presence of egg yolk as a source of lecithin. Although the venoms from M. spixii and N. nigricollis showed detectable thrombin-like activity, these and the other venoms were free of proteolytic activity when fibrin, gelatin and casein, were used as substrates. 5. When tested on mice skin, all five venoms were capable of inducing an increase in vascular permeability and oedema, but were devoid of haemorrhagic producing substances (haemorrhagins).(ABSTRACT TRUNCATED AT 250 WORDS) Images Figure 2 Figure 3 Figure 4 PMID:7921595

Tambourgi, D. V.; dos Santos, M. C.; Furtado, M. de F.; de Freitas, M. C.; da Silva, W. D.; Kipnis, T. L.

1994-01-01

327

Why Can’t Rodents Vomit? A Comparative Behavioral, Anatomical, and Physiological Study  

PubMed Central

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. PMID:23593236

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

328

Institute of Applied Ecology: African Mammals Databank  

NSDL National Science Digital Library

This impressive GIS-based databank focuses on the conservation and distribution of African mammals; and was developed collaboratively by the Geographic Information Systems Laboratory of the Animal and Human Biology Department at the University of Rome La Sapienza and the Institute of Applied Ecology. The databank covers the entire African continent, except Madagascar, â??and includes a total of 281 species, belonging to 12 orders and 28 families.â? Covered orders include Insectivora, Carnivora, Perissodactyla, Sirenia, Rodentia, Macroscelidae, and more. In addition to viewing information online, site visitors can download data, and information about project methodology.

329

New species and new records of mites of the genus Stigmaeus(Acari: Prostigmata: Stigmaeidae) from Crimea.  

PubMed

Three new species of the genus Stigmaeus Koch, 1836 (Acari: Stigmaeidae) are described from various habitats in Crimea: Stigmaeus kuznetsovi sp. nov. from nests of Microtus socialis (Rodentia: Cricetidae); S. mitrofanovi sp. nov. from galleries of Pityogenes bistridentatus (Coleoptera: Curculionidae) under the bark of Pinus pallasiana, and S. silvestris sp. nov. from rotten log of Pinus pallasiana. Stigmaeus corticeus Kuznetsov and Wainstein, 1977 and S. maraghehiensis Bagheri and Ueckermann, 2012 are recorded for the first time in Crimea. A key to species of the genus Stigmaeus of Crimea is provided. PMID:24870321

Khaustov, Alexander A

2014-01-01

330

[Analysis of genetic diversity of the Roborovski hamster (Phodopus roborovskii) in the northern part of its habitat].  

PubMed

An analysis of sequences of the cytochrome b gene and control region of mitochondrial DNA of 30 Roborovski hamsters (Phodopus roborovskii; Rodentia: Cricetinae) captured at ten geographical points from Zaisanskaya Depression (Kazakhstan) in the northwest to the Shilin-Gol area (China) in the southeast was conducted. The absence of a connection between the similarity of the discovered haplotypes and their geographical distribution allows us to assume that the modern genetic diversity of the species on the studied territory formed owing to migration waves from more southern areas. PMID:21442911

Meshcherski?, I G; Feoktistova, N Iu

2011-01-01

331

Cytogenetics of the South American akodont rodents (Cricetidae). IX. Chiasmatic sex bivalent in male meiosis of Akodon mollis.  

PubMed

Akodon mollis (Rodentia, Cricetidae) has a large subterminal Y chromosome measuring 5.24 percent of the haploid set. The long arm of the Y has a pattern of homology with the short arm of the X, as indicated by the similar distribution of G bands and by the formation of a chiasma in diakinesis and metaphase I of teste cells. Conversely, the short arm of the Y and the long arm of the X are nonhomologous and do not pair at meiosis. PMID:7047636

Semino, C; Oliveira, D; Bianchi, N O; Lobato, L

1982-01-01

332

On the highest chromosome number in mammals.  

PubMed

The mitotic and meiotic chromosomes of the semiaquatic rodent Ichthyomys pittieri (Rodentia, Cricetinae) from Venezuela were analyzed by means of conventional staining and several banding techniques. The diploid chromosome number of this rare species is 2n = 92, which is the highest value known for mammals. It is assumed that this exceptionally high chromosome number is the result of repeated centric fissions. The karyotype of I. pittieri was compared with that of Anotomys leander, for which a diploid number of 2n = 92 has also been reported. The karyological relationships existing within the Neotropical Cricetidae are summarized. PMID:3073914

Schmid, M; Fernández-Badillo, A; Feichtinger, W; Steinlein, C; Roman, J I

1988-01-01

333

Variance of molecular datings, evolution of rodents and the phylogenetic affinities between Ctenodactylidae and Hystricognathi.  

PubMed Central

The von Willebrand factor (vWF) gene has been used to understand the origin and timing of Rodentia evolution in the context of placental phylogeny vWF exon 28 sequences of 15 rodent families and eight non-rodent eutherian clades are analysed with two different molecular dating methods (uniform clock on a linearized tree; quartet dating). Three main conclusions are drawn from the study of this nuclear exon. First, Ctenodactylidae (gundis) and Hystricognathi (e.g. porcupines, guinea-pigs, chinchillas) robustly cluster together in a newly recognized clade, named 'Ctenohystrica'. The Sciurognathi monophyly is subsequently rejected. Pedetidae (springhares) is an independent and early diverging rodent lineage, suggesting a convergent evolution of the multiserial enamel of rodent incisors. Second, molecular date estimates are here more influenced by accuracy and choice of the palaeontological temporal references used to calibrate the molecular clock than by either characters analysed (nucleotides versus amino acids) or species sampling. The caviomorph radiation at 31 million years (Myr) and the pig porpoise split at 63 Myr appear to be reciprocally compatible dates. Third, during the radiation of Rodentia, at least three lineages (Gliridae, Sciuroidea and Ctenohystrica) emerged close to the Cretaceous-Tertiary boundary, and their common ancestor separated from other placental orders in the Late Cretaceous. PMID:10722222

Huchon, D; Catzeflis, F M; Douzery, E J

2000-01-01

334

Species Identification Key of Korean Mammal Hair  

PubMed Central

ABSTRACT The hair microstructures of Korean terrestrial mammals from 23 species (22 wild and one domestic) were analyzed using light and scanning electron microscopy (SEM) to construct a hair identification key. The hairs were examined using the medulla structures and cuticular scales of guard hairs from the dorsal regions of mature adult animals. All cuticular scale structures in the hair of Rodentia, Lagomorpha, Carnivora and Insectivora showed the petal pattern, and those of Artiodactyla and Chiroptera showed the wave pattern and coronal pattern, respectively. Rodentia, Lagomorpha and Carnivora showed multicellular, and Insectivora and Artiodactyla showed unicellular regular, mesh or columnar in the medulla structures, respectively. Chiroptera did not show the medulla structures in their hair. We found that it is possible to distinguish between species and order based on general appearance, medulla structures and cuticular scales. Thus, we constructed a hair identification key with morphological characteristics from each species. This study suggests that hair identification keys could be useful in fields, such as forensic science, food safety and foraging ecology. PMID:24451929

LEE, Eunok; CHOI, Tae-Young; WOO, Donggul; MIN, Mi-Sook; SUGITA, Shoei; LEE, Hang

2014-01-01

335

Reconstruction of karyotype evolution in core Glires. I. The genome homology revealed by comparative chromosome painting.  

PubMed

Glires represent a eutherian clade consisting of rodents and lagomorphs (hares, rabbits, and pikas). Chromosome evolution of Glires is known to have variable rates in different groups: from slowly evolving lagomorphs and squirrels to extremely rapidly evolving muroids. Previous interordinal homology maps between slowly evolving Glires were based on comparison with humans. Here, we used sets of chromosome-specific probes from Tamias sibiricus (Sciuridae), Castor fiber (Castoridae) and humans to study karyotypes of six ground squirrels (genera Marmota and Spermophilus) and one tree squirrel (genus Sciurus), mountain hare (genus Lepus), and rabbit (genus Oryctolagus). These data supplemented with GTG banding comparisons allowed us to build comparative chromosome maps. Our data showed the absence of previously found squirrel associations HSA 1/8 and 2/17 in the Eurasian ground squirrels--sousliks and woodchucks, and disruptions of squirrel HSA 10/13 and HSA 8/4/8/12/22 syntenies in the four Spermophilus species studied here. We found that the karyotypes of Sciuridae and Leporidae are highly conserved and close to the Rodentia ancestral karyotype, while Castoridae chromosomes underwent many more changes. We suggest that Lagomorpha and Sciuridae (in contrast to all other rodent families) should be considered as core Glires lineages, characterized by cytogenetically conserved karyotypes which contain chromosomal elements inherent to karyotype of common Glires ancestor. Our data allowed us to further refine the putative ancestral karyotypes of Rodentia. We also describe here the putative ancestral karyotypes of Glires and lagomorphs. PMID:21559983

Beklemisheva, Violetta R; Romanenko, Svetlana A; Biltueva, Larisa S; Trifonov, Vladimir A; Vorobieva, Nadezhda V; Serdukova, Natalya A; Rubtsova, Nadezhda V; Brandler, Oleg V; O'Brien, Patricia C M; Yang, Fentang; Stanyon, Roscoe; Ferguson-Smith, Malcolm A; Graphodatsky, Alexander S

2011-05-01

336

Species identification key of Korean mammal hair.  

PubMed

The hair microstructures of Korean terrestrial mammals from 23 species (22 wild and one domestic) were analyzed using light and scanning electron microscopy (SEM) to construct a hair identification key. The hairs were examined using the medulla structures and cuticular scales of guard hairs from the dorsal regions of mature adult animals. All cuticular scale structures in the hair of Rodentia, Lagomorpha, Carnivora and Insectivora showed the petal pattern, and those of Artiodactyla and Chiroptera showed the wave pattern and coronal pattern, respectively. Rodentia, Lagomorpha and Carnivora showed multicellular, and Insectivora and Artiodactyla showed unicellular regular, mesh or columnar in the medulla structures, respectively. Chiroptera did not show the medulla structures in their hair. We found that it is possible to distinguish between species and order based on general appearance, medulla structures and cuticular scales. Thus, we constructed a hair identification key with morphological characteristics from each species. This study suggests that hair identification keys could be useful in fields, such as forensic science, food safety and foraging ecology. PMID:24451929

Lee, Eunok; Choi, Tae-Young; Woo, Donggul; Min, Mi-Sook; Sugita, Shoei; Lee, Hang

2014-05-01

337

Unexpected primitive rodents in the Quaternary of Argentina  

NASA Astrophysics Data System (ADS)

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.

Vucetich, María G.; Vieytes, Emma C.; Verzi, Diego H.; Noriega, Jorge I.; Tonni, Eduardo P.

2005-10-01

338

Hepatitis B virus lineages in mammalian hosts: Potential for bidirectional cross-species transmission  

PubMed Central

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

Bonvicino, Cibele R; Moreira, Miguel A; Soares, Marcelo A

2014-01-01

339

Cryptosporidium muris in a reticulated giraffe (Giraffa camelopardalis reticulata).  

PubMed

Cryptosporidium spp. infection in captive exotic mammals was investigated using staining and molecular biological methods. A total of 323 fecal samples from 100 mammalian species (62 Artiodactyla, 33 Rodentia, 3 Perissodactyla, and 2 Paenungultata) in 4 zoological gardens in the Czech Republic was examined. Only in a reticulated giraffe (Giraffa camelopardalis reticulata) sample was Cryptosporidium sp. infection detected. The partial small subunit rRNA sequence obtained from the isolate was identical to sequences of Cryptosporidium muris in rock hyrax (Procavia capensis) and Bactrian camel (Camelus bactrianus). Neonatal BALB/c mice inoculated with 1 x 10(3) fresh oocysts of the C. muris giraffe isolate did not produce a detectable infection. PMID:19685941

Kodádková, A; Kvác, M; Ditrich, O; Sak, B; Xiao, L

2010-02-01

340

Rodents for comparative aging studies: from mice to beavers.  

PubMed

After humans, mice are the best-studied mammalian species in terms of their biology and genetics. Gerontological research has used mice and rats extensively to generate short- and long-lived mutants, study caloric restriction and more. Mice and rats are valuable model organisms thanks to their small size, short lifespans and fast reproduction. However, when the goal is to further extend the already long human lifespan, studying fast aging species may not provide all the answers. Remarkably, in addition to the fast-aging species, the order Rodentia contains multiple long-lived species with lifespans exceeding 20 years (naked mole-rat, beavers, porcupines, and some squirrels). This diversity opens great opportunities for comparative aging studies. Here we discuss the evolution of lifespan in rodents, review the biology of slow-aging rodents, and show an example of how the use of a comparative approach revealed that telomerase activity coevolved with body mass in rodents. PMID:19424861

Gorbunova, Vera; Bozzella, Michael J; Seluanov, Andrei

2008-09-01

341

Rodents for comparative aging studies: from mice to beavers  

PubMed Central

After humans, mice are the best-studied mammalian species in terms of their biology and genetics. Gerontological research has used mice and rats extensively to generate short- and long-lived mutants, study caloric restriction and more. Mice and rats are valuable model organisms thanks to their small size, short lifespans and fast reproduction. However, when the goal is to further extend the already long human lifespan, studying fast aging species may not provide all the answers. Remarkably, in addition to the fast-aging species, the order Rodentia contains multiple long-lived species with lifespans exceeding 20 years (naked mole-rat, beavers, porcupines, and some squirrels). This diversity opens great opportunities for comparative aging studies. Here we discuss the evolution of lifespan in rodents, review the biology of slow-aging rodents, and show an example of how the use of a comparative approach revealed that telomerase activity coevolved with body mass in rodents. PMID:19424861

Bozzella, Michael J.; Seluanov, Andrei

2008-01-01

342

The use of semen evaluation and assisted reproduction in Spix's macaws in terms of species conservation.  

PubMed

The Spix's macaw (Cyanopsitta spixii) is the rarest parrot on earth. The remaining captive population consists of 79 individuals. Captive propagation is ongoing to increase the number of individuals for future reintroduction back into the wild. Unfortunately, from 2004 to 2012, only 33 chicks hatched from 331 eggs. Semen evaluation and assisted reproduction might help to overcome this problem. Therefore, a recently developed electro-stimulated semen collection technique was used in Spix's macaws. Semen collection was successful in 39 of 78 attempts in 10 out of 17 males. Examination of the semen included evaluation of volume, color, consistency, contaminations and pH, as well as determination of motility, viability, morphology, concentration, and total count of spermatozoa. The median volume of semen samples was 5.6 µl. On average, 34.7 ± 21.9% (median 30%) of the sperm were motile and 23.1 ± 22.1% (median 16.5%) were progressively motile. In addition to spermatozoa, round cells were detected in the samples. Median sperm concentration was 15,500/µl (range 500-97,500/µl) and median viability was 50% (range 5-87%). Morphological examination revealed in 26.5% normal spermatozoa, high numbers of malformations of the head (50.2%) and tail region (20.5%), with 29% of all sperm showing multiple abnormalities. Artificial insemination was performed in three females; two eggs laid after artificial insemination had spermatozoa present on the perivitelline layer, suggesting the possible success of the insemination technique. Although no fertilization could be demonstrated, these preliminary results are promising, as they indicate that assisted reproduction might be a tool for species conservation in the Spix's macaw. PMID:24752991

Fischer, Dominik; Neumann, Daniel; Purchase, Cromwell; Bouts, Tim; Meinecke-Tillmann, Sabine; Wehrend, Axel; Lierz, Michael

2014-01-01

343

Linking fishery management and conservation in a tropical estuarine lagoon: biological and physical effects of an artisanal fishing gear  

NASA Astrophysics Data System (ADS)

Information coming from fishery monitoring, surveys and experimental fishing with participation of fishers was employed to determine the impact of an artisanal gear, 'boliche', on the biodiversity of the Ciénaga Grande de Santa Marta (CGSM), an estuarine lagoon on the Caribbean coast of Colombia. Fishery monitoring (catch data) included landings before (1968 and 1978) and after (1994-1996) the introduction of the boliche in the CGSM (1985), whereas surveys were conducted seasonally during 1993-1994. Fishing experiments involved evaluating different mesh sizes and the short-term effect of physical disturbance by the boliche. Monitoring suggested potential trophic effects of this fishing gear: the catch of large, long-lived, carnivorous species declined after the introduction of the boliche in the CGSM, whereas catch rates of smaller, shorter-lived, and lower trophic level species increased. Surveys revealed that the boliche retained 41 species. The by-catch made up 62% of the total catch and the remaining 38% involved the three target species Eugerres plumieri, Mugil incilis and Cathorops spixii. Selectivity experiments showed that 2.5 in. stretched mesh size gill nets caught more species than the 3.0-in. mesh. The smaller mesh also increased the risk of a critical reduction in the spawning stock of target species (notably E. plumieri); a situation that could affect the fish community if mesh sizes lower than 2.5 in. were intensively used. Suspended particulate matter significantly increased after fishing activity, with higher resuspension on mud-shells and mud substrata, whereas dissolved oxygen showed no appreciable changes after fishing operations. Notwithstanding, the activity of the boliche would generate sediment resuspension between 382 and 470 t day -1, which could lead to potential cascade impacts on water quality. We propose a framework of redundancy in management measures in order to simultaneously reach management and conservation goals.

Rueda, M.; Defeo, O.

2003-04-01

344

A newly emerged cutaneous leishmaniasis focus in northern Israel and two new reservoir hosts of Leishmania major.  

PubMed

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 Europe. PMID:23437408

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

345

Surprisingly low risk of overheating during digging in two subterranean rodents.  

PubMed

Capacities for and constraints of heat dissipation are considered to be important factors governing maximum intensity and duration of physical activity. Subterranean mammals are endurance diggers, but because of lack of air currents in their burrows, high relative humidity and other physical constraints, the capacity of common mammalian cooling mechanisms underground is very limited. We analyzed surface and body core temperature changes after digging in soft and hard substrates in two species of African mole-rats (Bathyergidae, Rodentia); the social giant mole-rat Fukomys mechowii and the solitary silvery mole-rat Heliophobius argenteocinereus. As expected, we observed an increase of body core temperature in both species after digging in both substrates. Surprisingly, and contrary to our expectations, we observed remarkable decrease of mole-rats' surface temperature immediately after the end of the digging trials. This decrease was greater in soft and moister soil than that in hard and drier soil. Our results suggest that mole-rats may effectively avoid overheating in burrows by effective cooling while digging, especially in wet soil. This indicates that burrowing in soils moistened by rains could be easier than previously thought contributing thus to mole-rats success in challenging environment of subterranean burrows. PMID:25446207

Okrouhlík, Jan; Burda, Hynek; Kunc, Petr; Knížková, Ivana; Šumbera, Radim

2015-01-01

346

Genomic and Bioinformatic Analysis of NADPH-Cytochrome P450 Reductase in Anopheles stephensi (Diptera: Culicidae).  

PubMed

The cytochrome P450 monooxygenase (P450) enzyme system is a major mechanism of xenobiotic biotransformation. The nicotinamide adenine dinucleotide phosphate (NADPH)-cytochrome P450 reductase (CPR) is required for transfer of electrons from NADPH to P450. One CPR gene was identified in the genome of the malaria-transmitting mosquito Anopheles stephensi Liston (Diptera: Culicidae). The gene encodes a polypeptide containing highly conserved flavin mononucleotide-, flavin adenine dinucleotide-, and NADPH-binding domains, a unique characteristic of the reductase. Phylogenetic analysis revealed that the A. stephensi and other known mosquito CPRs belong to a monophyletic group distinctly separated from other insects in the same order, Diptera. Amino acid residues of CPRs involved in binding of P450 and cytochrome c are conserved between A. stephensi and the Norway rat Rattus norvegicus Berkenhout (Rodentia: Muridae). However, gene structure particularly within the coding region is evidently different between the two organisms. Such difference might arise during the evolution process as also seen in the difference of P450 families and isoforms found in these organisms. CPR in the mosquito A. stephensi is expected to be active and serve as an essential component of the P450 system. PMID:25368081

Suwanchaichinda, C; Brattsten, L B

2014-01-01

347

Evolutionary Insights from a Genetically Divergent Hantavirus Harbored by the European Common Mole (Talpa europaea)  

PubMed Central

Background The discovery of genetically distinct hantaviruses in shrews (Order Soricomorpha, Family Soricidae) from widely separated geographic regions challenges the hypothesis that rodents (Order Rodentia, Family Muridae and Cricetidae) are the primordial reservoir hosts of hantaviruses and also predicts that other soricomorphs harbor hantaviruses. Recently, novel hantavirus genomes have been detected in moles of the Family Talpidae, including the Japanese shrew mole (Urotrichus talpoides) and American shrew mole (Neurotrichus gibbsii). We present new insights into the evolutionary history of hantaviruses gained from a highly divergent hantavirus, designated Nova virus (NVAV), identified in the European common mole (Talpa europaea) captured in Hungary. Methodology/Principal Findings Pair-wise alignment and comparison of the full-length S- and L-genomic segments indicated moderately low sequence similarity of 54–65% and 46–63% at the nucleotide and amino acid levels, respectively, between NVAV and representative rodent- and soricid-borne hantaviruses. Despite the high degree of sequence divergence, the predicted secondary structure of the NVAV nucleocapsid protein exhibited the characteristic coiled-coil domains at the amino-terminal end, and the L-segment motifs, typically found in hantaviruses, were well conserved. Phylogenetic analyses, using maximum-likelihood and Bayesian methods, showed that NVAV formed a distinct clade that was evolutionarily distant from all other hantaviruses. Conclusions Newly identified hantaviruses harbored by shrews and moles support long-standing virus-host relationships and suggest that ancestral soricomorphs, rather than rodents, may have been the early or original mammalian hosts. PMID:19582155

Kang, Hae Ji; Bennett, Shannon N.; Sumibcay, Laarni; Arai, Satoru; Hope, Andrew G.; Mocz, Gabor; Song, Jin-Won; Cook, Joseph A.; Yanagihara, Richard

2009-01-01

348

The power of social structure: how we became an intelligent lineage  

NASA Astrophysics Data System (ADS)

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.

de Sousa António, Marina Resendes; Schulze-Makuch, Dirk

2011-01-01

349

Revision of fleas of the genus Plocopsylla belonging to the 'angusticeps-lewisi' complex in the Andean biogeographic region, with the description of a new species.  

PubMed

In Argentina, the Andean biogeographic region accommodates the most diverse population of fleas in the country. The Craneopsyllinae (Siphonaptera: Stephanocircidae) represent one of the most commonly found subfamilies in this region and show some endemism and high diversity. Plocopsylla is the most diverse genus of Craneopsyllinae; it includes 10 species mainly distributed in the Patagonian subregion, which parasitize sigmodontine rodents (Rodentia: Cricetidae). We describe and illustrate the morphology of the aedeagus in species of Plocopsylla that belong to the 'angusticeps-lewisi' complex. This character is of diagnostic value in differentiating among species. A new species of this complex, Plocopsylla (Plocopsylla) linardii sp. n., is described and identified by the shape and chaetotaxy of the distal arm of sternite IX, as well as by the shape of the median dorsal lobe of the aedeagus. New host associations for this complex and range extensions for most of its species are reported. Plocopsylla (P.) silewi is recorded for the first time in Argentina. The southern limits of the distributions of Plocopsylla (P.) lewisi and Plocopsylla (P.) wilesi are extended to Santa Cruz Province. The angusticeps-lewisi complex is found for the first time in San Juan Province. The information may be useful in epidemiological studies of flea-borne diseases. PMID:25726809

Sanchez, J; Beaucournu, J-C; Lareschi, M

2015-06-01

350

Hystricognathy vs sciurognathy in the rodent jaw: a new morphometric assessment of hystricognathy applied to the living fossil Laonastes (Diatomyidae).  

PubMed

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

Hautier, Lionel; Lebrun, Renaud; Saksiri, Soonchan; Michaux, Jacques; Vianey-Liaud, Monique; Marivaux, Laurent

2011-01-01

351

Microsatellite-encoded domain in rodent Sry functions as a genetic capacitor to enable the rapid evolution of biological novelty  

PubMed Central

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. PMID:23901118

Chen, Yen-Shan; Racca, Joseph D.; Sequeira, Paul W.; Phillips, Nelson B.; Weiss, Michael A.

2013-01-01

352

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

NASA Astrophysics Data System (ADS)

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.

Oliveriusová, Ludmila; N?mec, Pavel; Pavelková, Zuzana; Sedlá?ek, František

2014-07-01

353

Magnetic compass orientation in two strictly subterranean rodents: learned or species-specific innate directional preference?  

PubMed

Evidence for magnetoreception in mammals remains limited. Magnetic compass orientation or magnetic alignment has been conclusively demonstrated in only a handful of mammalian species. The functional properties and underlying mechanisms have been most thoroughly characterized in Ansell's mole-rat, Fukomys anselli, which is the species of choice due to its spontaneous drive to construct nests in the southeastern sector of a circular arena using the magnetic field azimuth as the primary orientation cue. Because of the remarkable consistency between experiments, it is generally believed that this directional preference is innate. To test the hypothesis that spontaneous southeastern directional preference is a shared, ancestral feature of all African mole-rats (Bathyergidae, Rodentia), we employed the same arena assay to study magnetic orientation in two other mole-rat species, the social giant mole-rat, Fukomys mechowii, and the solitary silvery mole-rat, Heliophobius argenteocinereus. Both species exhibited spontaneous western directional preference and deflected their directional preference according to shifts in the direction of magnetic north, clearly indicating that they were deriving directional information from the magnetic field. Because all of the experiments were performed in total darkness, our results strongly suggest that all African mole-rats use a light-independent magnetic compass for near-space orientation. However, the spontaneous directional preference is not common and may be either innate (but species-specific) or learned. We propose an experiment that should be performed to distinguish between these two alternatives. PMID:22855619

Oliveriusová, Ludmila; N?mec, Pavel; Králová, Zuzana; Sedlá?ek, František

2012-10-15

354

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

PubMed

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. PMID:24913128

Oliveriusová, Ludmila; N?mec, Pavel; Pavelková, Zuzana; Sedlá?ek, František

2014-07-01

355

HIF-1? regulation in mammalian hibernators: role of non-coding RNA in HIF-1? control during torpor in ground squirrels and bats.  

PubMed

A potential role for non-coding RNAs, miR-106b and antisense hypoxia inducible transcription factor-1 (HIF-1?), in HIF-1? regulation during mammalian hibernation was investigated in two species, the thirteen-lined ground squirrel (Ictidomys tridecemlineatus) and the little brown bat (Myotis lucifugus). Both species showed differential regulation of HIF-1? during hibernation. HIF-1? protein levels increased significantly in skeletal muscle of both species when animals entered torpor, as well as in bat liver. HIF-1? mRNA levels correlated with the protein increase in bat skeletal muscle and liver but not in squirrel skeletal muscle. Antisense HIF-1? transcripts were identified in skeletal muscle of both hibernators. The expression of antisense HIF-1? was reduced in skeletal muscle of torpid bats compared with euthermic controls, suggesting that release of inhibition by the antisense RNA contributes to regulating HIF-1? translation in this tissue during torpor. The expression of miR-106b, a microRNA associated with HIF-1? regulation, also decreased during torpor in both skeletal muscle and liver of bats and in ground squirrel skeletal muscle. These data present the first evidence that non-coding RNA provides novel post-transcriptional mechanisms of HIF-1? regulation when hibernators descend into deep cold torpor, and also demonstrate that these mechanisms are conserved in two divergent mammalian orders (Rodentia and Chiroptera). PMID:22526261

Maistrovski, Yulia; Biggar, Kyle K; Storey, Kenneth B

2012-08-01

356

Wild and synanthropic reservoirs of Leishmania species in the Americas  

PubMed Central

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

Roque, André Luiz R.; Jansen, Ana Maria

2014-01-01

357

Evolution of genome organizations of squirrels (Sciuridae) revealed by cross-species chromosome painting.  

PubMed

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. PMID:15241012

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

358

The "five-sites" rule and the evolution of red and green color vision in mammals.  

PubMed

Amino acid changes S180A (S-->A at site 180), H197Y, Y277F, T285A, and A308S are known to shift the maximum wavelength of absorption (lambda max) of red and green visual pigments toward blue, essentially in an additive fashion. To test the generality of this "five-sites" rule, we have determined the partial amino acid sequences of red and green pigments from five mammalian orders (Artiodactyla, Carnivora, Lagomorpha, Perissodactyla, and Rodentia). The result suggests that cat (Felis catus), dog (Canis familiaris), and goat (Capra hircus) pigments all with AHYTA at the five critical sites have lambda max values of approximately 530 nm, whereas rat (Rattus norvegicus) pigment with AYYTS has a lambda max value of approximately 510 nm, which is accurately predicted by the five-sites rule. However, the observed lambda max values of the orthologous pigments of European rabbit (Oryctolagus cuniculus), white-tailed deer (Odocoileus virginianus), gray squirrel (Sciurus carolinensis), and guinea pig (Cavia procellus) are consistently more than 10 nm higher than the predicted values, suggesting the existence of additional molecular mechanisms for red and green color vision. The inferred amino acid sequences of ancestral organisms suggest that the extant mammalian red and green pigments appear to have evolved from a single ancestral green-red hybrid pigment by directed amino acid substitutions. PMID:9580985

Yokoyama, S; Radlwimmer, F B

1998-05-01

359

Implications of hybridization, NUMTs, and overlooked diversity for DNA Barcoding of Eurasian ground squirrels.  

PubMed

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

Ermakov, Oleg A; Simonov, Evgeniy; Surin, Vadim L; Titov, Sergey V; Brandler, Oleg V; Ivanova, Natalia V; Borisenko, Alex V

2015-01-01

360

New Species of Rotundomys (Cricetinae) from the Late Miocene of Spain and Its Bearing on the Phylogeny of Cricetulodon and Rotundomys  

PubMed Central

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

López-Antoñanzas, Raquel; Peláez-Campomanes, Pablo; Álvarez-Sierra, Ángeles

2014-01-01

361

Positive Selection and the Evolution of izumo Genes in Mammals  

PubMed Central

Most genes linked to male reproductive function have been known to evolve rapidly among species and to show signatures of positive selection. Different male species-specific reproductive strategies have been proposed to underlie positive selection, such as sperm competitive advantage and control over females postmating physiology. However, an underexplored aspect potentially affecting male reproductive gene evolution in mammals is the effect of gene duplications. Here we analyze the molecular evolution of members of the izumo gene family in mammals, a family of four genes mostly expressed in the sperm with known and potential roles in sperm-egg fusion. We confirm a previously reported bout of selection for izumo1 and establish that the bout of selection is restricted to the diversification of species of the superorder Laurasiatheria. None of the izumo genes showed evidence of positive selection in Glires (Rodentia and Lagomorpha), and in the case of the non-testes-specific izumo4, rapid evolution was driven by relaxed selection. We detected evidence of positive selection for izumo3 among Primates. Interestingly, positively selected sites include several serine residues suggesting modifications in protein function and/or localization among Primates. Our results suggest that positive selection is driven by aspects related to species-specific adaptations to fertilization rather than sexual selection. PMID:22957301

Grayson, Phil; Civetta, Alberto

2012-01-01

362

DNA-based and geometric morphometric analysis to validate species designation: a case study of the subterranean rodent Ctenomys bicolor.  

PubMed

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. PMID:24301764

Stolz, J F B; Gonçalves, G L; Leipnitz, L; Freitas, T R O

2013-01-01

363

Jumping and gliding rodents: mitogenomic affinities of Pedetidae and Anomaluridae deduced from an RNA-Seq approach.  

PubMed

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. PMID:23973722

Fabre, Pierre-Henri; Jønsson, Knud A; Douzery, Emmanuel J P

2013-12-01

364

More Novel Hantaviruses and Diversifying Reservoir Hosts — Time for Development of Reservoir-Derived Cell Culture Models?  

PubMed Central

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. PMID:24576845

Eckerle, Isabella; Lenk, Matthias; Ulrich, Rainer G.

2014-01-01

365

Characterization of the North American beaver (Castor canadensis) papillomavirus genome.  

PubMed

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. PMID:24309404

Rogovskyy, Artem S; Chen, Zigui; Burk, Robert D; Bankhead, Troy

2014-01-10

366

Implications of Hybridization, NUMTs, and Overlooked Diversity for DNA Barcoding of Eurasian Ground Squirrels  

PubMed Central

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

Ermakov, Oleg A.; Simonov, Evgeniy; Surin, Vadim L.; Titov, Sergey V.; Brandler, Oleg V.; Ivanova, Natalia V.; Borisenko, Alex V.

2015-01-01

367

Sound localization in a predatory rodent, the northern grasshopper mouse (Onychomys leucogaster).  

PubMed

A comparison of the ability of mammals to localize sound revealed that among the animals examined to date, none of the rodents have been able to localize as accurately as the carnivores. Because all of these rodents are prey animals, the question arises as to whether their poor localization acuity is a phyletic trait of Rodentia or whether it is a trait common to prey species that may be under less selective pressure than predators to localize sound accurately. To answer this question, sound localization acuity was determined in a species that is both predatory and a rodent, the northern grasshopper mouse. Localization thresholds for a single 100-ms noise burst were determined for three grasshopper mice using a conditioned avoidance procedure. Their 50% discrimination threshold of 19 degrees is larger than that of any of the previously tested carnivores and well within the range of other rodents. However, calculations of the binaural sound localization cues available to rodents (based on their head size) suggest that the grasshopper mouse may make more efficient use of the available locus cues than other rodents. Thus, although the grasshopper mouse cannot localize as accurately as carnivores, it appears to be more accurate than predicted for a nonpredatory rodent of its size. PMID:3365945

Heffner, R S; Heffner, H E

1988-03-01

368

Comparison of the ITS1 and ITS2 rDNA in Eimeria callospermophili (Apicomplexa:Eimeriidae) from sciurid rodents.  

PubMed

The taxonomy of the coccidia has historically been morphologically based. The purpose of this study was to establish if conspecificity of isolates of Eimeria callospermophili from 4 ground-dwelling squirrel hosts (Rodentia: Sciuridae) is supported by comparison of rDNA sequence data and to examine how this species relates to eimerian species from other sciurid hosts. Eimeria callospermophili was isolated from 4 wild-caught hosts, i.e., Urocitellus elegans, Cynomys leucurus, Marmota flaviventris , and Cynomys ludovicianus . The ITS1 and ITS2 genomic rDNA sequences were PCR generated, sequenced, and analyzed. The highest intraspecific pairwise distance values of 6.0% in ITS1 and 7.1% in ITS2 were observed in C. leucurus. Interspecific pairwise distance values > 5% do not support E. callospermophili conspecificity. Generated E. callospermophili sequences were compared to Eimeria lancasterensis from Sciurus niger and Sciurus niger cinereus and to Eimeria ontarioensis from S. niger. A single, well-supported clade was formed by E. callospermophili amplicons in neighbor joining and maximum parsimony analyses. However, within the clade, there was little evidence of host or geographic structuring of the species. PMID:21506777

Motriuk-Smith, Dagmara; Seville, R Scott; Quealy, Leah; Oliver, Clinton E

2011-04-01

369

Energetics of hibernating yellow-bellied marmots (Marmota flaviventris).  

PubMed

Yellow-bellied marmots (Rodentia: Sciuridae) typically hibernate for eight months. This study explored energetic costs of hibernation in young and adults at 10 and 6 degrees C. Age significantly affected the percent time torpid, total and mass-specific VO(2), use of energy during torpor, and daily mass loss at 6 degrees C. Thus young had a higher mass-specific VO(2) during a torpor bout, which was attributed to higher metabolism during deep torpor. Total VO(2) during a bout was higher in young and there were significant temperature/age interactions; young had a higher VO(2) during torpor and deep torpor at 6 degrees C than at 10 degrees C. VO(2) increased at T(E)s below 6 degrees C. Young had a higher daily mass loss than adults at 6 degrees C. Euthermy increased energetic costs 19.3 times over those of torpor and 23.5 times over those of deep torpor. Energy costs are minimized by spending 88.6% of the hibernation period in torpor, by the rapid decline of VO(2) from euthermy to torpor and by allowing T(B) to decline at low T(E). Torpidity results in average energy savings during winter of 83.3% of the costs of maintaining euthermy. Energy savings are greater than those reported for Marmota marmota and M. monax. PMID:12507613

Armitage, Kenneth B; Blumstein, Daniel T; Woods, Brett C

2003-01-01

370

Comparison of the ITS1 and ITS2 rDNA in Emeria callospermophili (Apicomplexa: Eimeriidae) from Sciurid Rodents  

PubMed Central

The taxonomy of the coccidia has historically been morphologically based. The purpose of this study was to establish if conspecificity of isolates of Eimeria callospermophili from 4 ground-dwelling squirrel hosts (Rodentia: Sciuridae) is supported by comparison of rDNA sequence data and to examine how this species relates to eimerian species from other sciurid hosts. Eimeria callospermophili was isolated from 4 wild caught hosts, i.e., Urocitellus elegans, Cynomys leucurus, Marmota flaviventris, and Cynomys ludovicianus. The ITS1 and ITS2 genomic rDNA sequences were PCR generated, sequenced, and analyzed. The highest intraspecific pairwise distance values of 6.0% in ITS1 and 7.1% in ITS2 were observed in C. leucurus. Interspecific pairwise distance values greater than 5% do not support E. callospermophili conspecificity. Generated E. callospermophili sequences were compared to Eimeria lancasterensis from Sciuris niger and Sciurus niger cinereus, and Eimeria ontarioensis from S. niger. A single well-supported clade was formed by E. callospermophili amplicons in Neighbor Joining and Maximum Parsimony analyses. However, within the clade there was little evidence of host or geographic structuring of the species. PMID:21506777

Motriuk-Smith, Dagmara; Seville, R Scott; Quealy, Leah; Oliver, Clinton E.

2011-01-01

371

Evolution of hantaviruses: co-speciation with reservoir hosts for more than 100 MYR.  

PubMed

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. PMID:24463501

Plyusnin, Alexander; Sironen, Tarja

2014-07-17

372

Chlamydiaceae and Chlamydia-like organisms in free-living small mammals in Europe and Afghanistan.  

PubMed

Few data are available on the occurrence of chlamydial infections in wild small mammals. We investigated the significance of free-living small mammals as reservoirs or transmission hosts for microorganisms of the phylum/class Chlamydiae. We obtained 3,664 tissue samples from 911 animals in Switzerland, Germany, Austria, the Czech Republic, and Afghanistan. Samples included internal organs (n = 3,652) and feces (n = 12) from 679 rodents (order Rodentia) and 232 insectivores (order Soricomorpha) and were tested by three TaqMan® real-time PCRs specific for members of the family Chlamydiaceae and selected Chlamydia-like organisms such as Parachlamydia spp. and Waddlia spp. Only one of 911 (0.11%) animals exhibited a questionable positive result by Chlamydiaceae-specific real-time PCR. Five of 911 animals were positive by specific real-time PCR for Parachlamydia spp. but could not be confirmed by quantitative PCR targeting the Parachlamydia acanthamoebae secY gene (secY qPCR). One of 746 animals (0.13%) was positive by real-time PCR for Waddlia chondrophila. This result was confirmed by Waddlia secY qPCR. This is the first detection of Chlamydia-like organisms in small wildlife in Switzerland. Considering previous negative results for Chlamydiaceae in wild ruminant species from Switzerland, these data suggest that wild small mammals are unlikely to be important carriers or transport hosts for Chamydiaceae and Chlamydia-like organisms. PMID:24484495

Stephan, Sarah; Guerra, Diogo; Pospischil, Andreas; Hilbe, Monika; Weissenböck, Herbert; Novotný, Ladislav; Greub, Gilbert; Croxatto, Antony; Teifke, Jens Peter; Ulrich, Rainer G; Schlegel, Mathias; Ruhl, Silke; Schotte, Ulrich; Binder, Alfred; Sauer, Sabine; Borel, Nicole

2014-04-01

373

The ecology of the Trypanosoma cruzi transmission cycle: Dispersion of zymodeme 3 (Z3) in wild hosts from Brazilian biomes.  

PubMed

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. PMID:19643545

Lisboa, Cristiane Varella; Xavier, Samanta Cristina das Chagas; Herrera, Heitor Miraglia; Jansen, Ana Maria

2009-10-28

374

A comparative survey of the mast cells of the mammalian brain.  

PubMed Central

A search for mast cells has been made in the brains of 18 mammalian species in 13 families in the orders Insectivora, Primates, Rodentia and Carnivora. In the larger animals, only the diencephalon and olfactory bulbs were examined. Mast cells were identified by virtue of their heparin-containing granules, which are stained by Alcian blue 8GX and, metachromatically, by toluidine blue 0. Within the cerebral parenchyma, mast cells were confined to the dorsal diencephalon of Erinaceus europaeus (hedgehog), Tupaia glis (tree-shrew) and Nycticebus coucang (slow loris). Some cells were next to capillaries; others were not. Mast cells were sometimes found, though rarely, in the intracerebral perivascular connective tissue leptomeninges and choroid plexuses of some of the other species examined. It is concluded that pericapillary cells (pericytes), which have been called mast cells by some investigators, are not in fact mast cells since there is no evidence for the presence of heparin. The functions of mast cells in the brain are unknown. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 PMID:819404

Kiernan, J A

1976-01-01

375

Seed predation and fruit damage of Solanum lycocarpum (Solanaceae) by rodents in the cerrado of central Brazil  

NASA Astrophysics Data System (ADS)

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.

Briani and, Denis C., Jr.; Guimarães, Paulo R.

2007-01-01

376

Shared Ancestry between a Newfound Mole-Borne Hantavirus and Hantaviruses Harbored by Cricetid Rodents ?†  

PubMed Central

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. PMID:21632770

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

2011-01-01

377

Ectoparasites of the Pallas squirrel, Callosciurus erythraeus, introduced to Japan.  

PubMed

The squirrel Callosciurus erythraeus (Pallas) (Rodentia: Sciuridae) was intentionally introduced to Japan in 1935 and has become established throughout much of the country. Although they live mainly in forests, Pallas squirrels come into gardens and are frequently fed by people or kept as pets, so their ectoparasites could be of potential medical as well as veterinary importance. During 2001-2003 we conducted the first ectoparasite survey of Pallas squirrels in Japan. From 105 C. erythraeus captured in Kamakura District of Kanagawa Prefecture on Honshu Island, three types of ectoparasite were found: 52 specimens of the sucking louse Neohaematopinus callosciuri Johnson (Anoplura: Haematopinidae), 26 fleas Ceratophyllus (Monopsyllus) anisus Rothschild (Siphonaptera: Ceratophyllidae) and four nymphs of the tick Haemaphysalis flava Neumann (Acari: Ixodidae) on 22, 13 and one squirrels, respectively. Evidently in Japan C. erythraeus carries relatively few ectoparasite species; this may be a contributory factor to their invasive success. Further investigations are needed to assess risks of zoonotic transmission of plague or murine typhus by C. anisus, of louse-borne typhus by N. callosciuri and of tularaemia and especially Japanese spotted fever (Rickettsia japonica) by H. flava. PMID:15009447

Shinozaki, Y; Shiibashi, T; Yoshizawa, K; Murata, K; Kimura, J; Maruyama, S; Hayama, Y; Yoshida, H; Nogami, S

2004-03-01

378

Identification of potential hosts and vectors of scrub typhus and tick-borne spotted fever group rickettsiae in eastern Taiwan.  

PubMed

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. PMID:21223345

Kuo, C C; Huang, C L; Wang, H C

2011-06-01

379

Faster Speciation and Reduced Extinction in the Tropics Contribute to the Mammalian Latitudinal Diversity Gradient  

PubMed Central

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

Rolland, Jonathan; Condamine, Fabien L.; Jiguet, Frederic; Morlon, Hélène

2014-01-01

380

Evolution of C, D and S-Type Cystatins in Mammals: An Extensive Gene Duplication in Primates  

PubMed Central

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. PMID:25329717

de Sousa-Pereira, Patrícia; Abrantes, Joana; Pinheiro, Ana; Colaço, Bruno; Vitorino, Rui; Esteves, Pedro J.

2014-01-01

381

Deterioration of the G?o Vomeronasal Pathway in Sexually Dimorphic Mammals  

PubMed Central

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 G?i2 protein project to the rostral portion of the AOB and respond mostly to small volatile molecules, whereas neurons expressing G?o project to the caudal AOB and respond mostly to large non-volatile molecules. However, the G?o-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 G?o pathway belong to Laurasiatheria and Primates lineages, both clades with ubiquitous sexual dimorphisms across species. To assess whether similar events of G?o 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 G?i2-protein throughout AOB glomeruli, while G?o expression is restricted to main olfactory glomeruli only. Our results suggest that the degeneration of the G?o-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

Suárez, Rodrigo; Fernández-Aburto, Pedro; Manger, Paul R.; Mpodozis, Jorge

2011-01-01

382

Characterization and phylogenetic utility of the mammalian protamine p1 gene.  

PubMed

We sequenced the protamine P1 gene (ca. 450 bp) from 20 bats (order Chiroptera) and the flying lemur (order Dermoptera). We compared these sequences with published sequences from 19 other mammals representing seven orders (Artiodactyla, Carnivora, Cetacea, Perissodactyla, Primates, Proboscidea, and Rodentia) to assess structure, base compositional bias, and phylogenetic utility. Approximately 80% of second codon positions were guanine, resulting in protamine proteins containing a high frequency of arginine residues. Our data indicate that codon usage for arginine differs among higher mammalian taxa. Parsimony analysis of 40 species representing nine orders produced a well-resolved tree in which most nodes were supported strongly, except at the lowest taxonomic levels (e.g., within Artiodactyla and Vespertilionidae). These data support monophyly of several taxa proposed by morphologic and molecular studies (all nine orders: Laurasiatheria, Cetartiodactytla, Yangochiroptera, Noctilionoidea, Rhinolophoidea, Vespertilionoidea, Phyllostomidae, Natalidae, and Vespertilionidae) and, in agreement with recent molecular studies, reject monophyly of Archonta, Volitantia, and Microchiroptera. Bats were sister to a clade containing Perissodactyla, Carnivora, and Cetartiodactyla, and, although not unequivocally, rhinolophoid bats (traditional microchiropterans) were sister to megachiropterans. Sequences of the protamine P1 gene are useful for resolving relationships at and above the familial level in bats, and generally within and among mammalian orders, but with some drawbacks. The coding and intervening sequences are small, producing few phylogenetically informative characters, and aligning the intron is difficult, even among closely related families. Given these caveats, the protamine P1 gene may be important to future systematic studies because its functional and evolutionary constraints differ from other genes currently used in systematic studies. PMID:11884158

Van Den Bussche, Ronald A; Hoofer, Steven R; Hansen, Eric W

2002-03-01

383

Next-Generation Sequencing for Rodent Barcoding: Species Identification from Fresh, Degraded and Environmental Samples  

PubMed Central

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. PMID:23144869

Galan, Maxime; Pagès, Marie; Cosson, Jean-François

2012-01-01

384

Coypu insulin. Primary structure, conformation and biological properties of a hystricomorph rodent insulin.  

PubMed

Insulin from a hystricomorph rodent, coypu (Myocaster coypus), was isolated and purified to near homogeneity. Like the other insulins that have been characterized in this Suborder of Rodentia, coypu insulin also exhibits a very low (3%) biological potency, relative to pig insulin, on lipogenesis in isolated rat fat-cells. The receptor-binding affinity is significantly higher (5-8%) in rat fat-cells, in rat liver plasma membranes and in pig liver cells, indicating that the efficacy of coypu insulin on receptors is about 2-fold lower than that of pig insulin. The primary structures of the oxidized A- and B-chains were determined, and our sequence analysis confirms a previous report [Smith (1972) Diabetes 21, Suppl. 2, 457-460] that the C-terminus of the A-chain is extended by a single residue (i.e. aspartate-A22), in contrast with most other insulin sequences, which terminate at residue A21. In spite of a large number of amino acid substitutions (relative to mammalian insulins), computer-graphics model-building studies suggest a similar spatial arrangement for coypu insulin to that for pig insulin. The substitution of the zinc-co-ordinating site (B10-His----Gln) along with various substitutions on the intermolecular surfaces involved in the formation of higher aggregates are consistent with the observation that this insulin is predominantly 'monomeric' in nature. The c.d. spectrum of coypu insulin is relatively similar to those of casiragua insulin and of bovine insulin at low concentration. PMID:3541911

Bajaj, M; Blundell, T L; Horuk, R; Pitts, J E; Wood, S P; Gowan, L K; Schwabe, C; Wollmer, A; Gliemann, J; Gammeltoft, S

1986-09-01

385

Threat Diversity Will Erode Mammalian Phylogenetic Diversity in the Near Future  

PubMed Central

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 significant impact on future mammalian phylogeny. PMID:23029443

Jono, Clémentine M. A.; Pavoine, Sandrine

2012-01-01

386

Light Perception in Two Strictly Subterranean Rodents: Life in the Dark or Blue?  

PubMed Central

Background The African mole-rats (Bathyergidae, Rodentia) are strictly subterranean, congenitally microphthalmic rodents that are hardly ever exposed to environmental light. Because of the lack of an overt behavioural reaction to light, they have long been considered to be blind. However, recent anatomical studies have suggested retention of basic visual capabilities. In this study, we employed behavioural tests to find out if two mole-rat species are able to discriminate between light and dark, if they are able to discriminate colours and, finally, if the presence of light in burrows provokes plugging behaviour, which is assumed to have a primarily anti-predatory function. Methodology/Principal Finding We used a binary choice test to show that the silvery mole-rat Heliophobius argenteocinereus and the giant mole-rat Fukomys mechowii exhibit a clear photoavoidance response to full-spectrum (“white”), blue and green-yellow light, but no significant reaction to ultraviolet or red light during nest building. The mole-rats thus retain dark/light discrimination capabilities and a capacity to perceive short to medium-wavelength light in the photopic range of intensities. These findings further suggest that the mole-rat S opsin has its absorption maximum in the violet/blue part of the spectrum. The assay did not yield conclusive evidence regarding colour discrimination. To test the putative role of vision in bathyergid anti-predatory behaviour, we examined the reaction of mole-rats to the incidence of light in an artificial burrow system. The presence of light in the burrow effectively induced plugging of the illuminated tunnel. Conclusion/Significance Our findings suggest that the photopic vision is conserved and that low acuity residual vision plays an important role in predator avoidance and tunnel maintenance in the African mole-rats. PMID:20676369

Kott, Ond?ej; Šumbera, Radim; N?mec, Pavel

2010-01-01

387

Evidence for rodent-common and species-typical limb and digit use in eating, derived from a comparative analysis of ten rodent species.  

PubMed

Order Rodentia comprises a vast portion of mammalian species (1814 species), which occupy extremely diverse habitats requiring very distinct motor specializations (e.g. burrowing, hopping, climbing, flying and swimming). Although early classification of paw use ability suggests rodents are impoverished relative to primates and make little use of their paws, there have been no systematic investigations of paw use in rodents. The present study was undertaken to describe limb/paw movements in a variety of common rodents. The movements used for handling sunflower seeds and other foods were videorecorded and analyzed in the guinea pig (Cavia porcellus), Mongolian gerbil (Meriones unguiculatus), Syrian hamster (Mesocricetus auratus), laboratory mouse (Mus musculus), laboratory rat (Rattus norvegicus), gray squirrel (Sciurus carolinensis), red squirrel (Tamiasciurus hudsonicus), Richardson's ground squirrel (Spermophilus richardsonni), prairie dog (Cynomus parvidens), and Canadian beaver (Castor americanus). The results suggested five order-common movements of food handling: (1) locating food by sniffing, (2) grasping food by mouth, (3) sitting back on the haunches to eat, (4) grasping the food using an elbow-in movement, and (5) manipulate the food with the digits. Different species displayed species-typical specializations including (1) bilateral grasping with the paws (gerbil), (2) unilateral grasping with a paw (beaver), (3) unilateral holding (ground squirrels), (4) various grip and digit postures (all species), (5) unilateral object removal from the mouth (gerbil), (6) bilateral thumb holding (squirrels), and (7) simultaneous holding/manipulation of two objects (squirrels). Only the guinea pig did not handle food with its paws, suggesting its behavior is regressive. The existence of a core pattern of paw and digit use in rodents suggests that skilled limb and paw movements originate at least with the common ancestors of the rodent, and likely the common ancestor to rodent and primate lineages, while species-typical movements suggest specialization/regression of limb use has occurred in a number of mammalian orders. PMID:9821545

Whishaw, I Q; Sarna, J R; Pellis, S M

1998-11-01

388

Small mammal survival and trapability in mark-recapture monitoring programs for hantavirus.  

PubMed

Following the 1993 hantavirus pulmonary syndrome (HPS) epidemic in the south-western United States, mammalogists and epidemiologists instituted long-term studies to monitor population density and prevalence of infection in rodents which constitute the reservoir for Sin Nombre virus (SNV). In this study, field techniques used in sampling small mammals for SNV infection were evaluated to determine if trapping and handling protocols were having significant effects on future trapability or mortality of animals. We compared rodent mark-recapture control plots, on which all rodents were simply measured, marked, and released on site, with experimental plots on which all animals were anesthetized with methoxyflurane, sampled for blood and saliva, measured, marked, and released. Blood samples were obtained from anesthetized animals on the experimental plots via a retro-orbital sinus puncture using a heparinized capillary tube. Dacron tipped oral swabs were used to collect buccal cells and saliva from the rodent's oral cavity. Field data were collected monthly from August 1994 to August 1996 at two sites in New Mexico (USA). Analyses were based on 3,661 captures of 1,513 individuals representing 21 species from three rodent families (Rodentia: Muridae, Heteromyidae, Sciuridae) and two species of rabbits (Lagomorpha: Leporidae). Overall, for most murid rodents (including five Peromyscus spp., Neotoma albigula, and Onychomys leucogaster) and one rabbit species (Sylvilagus floridanus), the handling/bleeding procedures had no significant effects on recapture rates or mortality. In contrast, several species of heteromyids (Dipodomys ordii and Perognathus flavus), one murid (Reithrodontomys megalotis) and one leporid (S. auduboni) suffered higher mortality rates, and heteromyid kangaroo rats (D. ordii and D. merriami) exhibited lower trapability as a result of the anesthesia and sampling procedures. In view of the overall non-significant influence of the sampling procedures on murid rodents, the anesthesia and blood/saliva sampling protocols described herein appear to be appropriate for hantavirus research, and may serve as a model for environmental monitoring of other zoonotic agents and their reservoirs. PMID:9476220

Parmenter, C A; Yates, T L; Parmenter, R R; Mills, J N; Childs, J E; Campbell, M L; Dunnum, J L; Milner, J

1998-01-01

389

Coalescent-Based Genome Analyses Resolve the Early Branches of the Euarchontoglires  

PubMed Central

Despite numerous large-scale phylogenomic studies, certain parts of the mammalian tree are extraordinarily difficult to resolve. We used the coding regions from 19 completely sequenced genomes to study the relationships within the super-clade Euarchontoglires (Primates, Rodentia, Lagomorpha, Dermoptera and Scandentia) because the placement of Scandentia within this clade is controversial. The difficulty in resolving this issue is due to the short time spans between the early divergences of Euarchontoglires, which may cause incongruent gene trees. The conflict in the data can be depicted by network analyses and the contentious relationships are best reconstructed by coalescent-based analyses. This method is expected to be superior to analyses of concatenated data in reconstructing a species tree from numerous gene trees. The total concatenated dataset used to study the relationships in this group comprises 5,875 protein-coding genes (9,799,170 nucleotides) from all orders except Dermoptera (flying lemurs). Reconstruction of the species tree from 1,006 gene trees using coalescent models placed Scandentia as sister group to the primates, which is in agreement with maximum likelihood analyses of concatenated nucleotide sequence data. Additionally, both analytical approaches favoured the Tarsier to be sister taxon to Anthropoidea, thus belonging to the Haplorrhine clade. When divergence times are short such as in radiations over periods of a few million years, even genome scale analyses struggle to resolve phylogenetic relationships. On these short branches processes such as incomplete lineage sorting and possibly hybridization occur and make it preferable to base phylogenomic analyses on coalescent methods. PMID:23560065

Kumar, Vikas; Hallström, Björn M.; Janke, Axel

2013-01-01

390

Development of Rapidly Evolving Intron Markers to Estimate Multilocus Species Trees of Rodents  

PubMed Central

One of the major challenges in the analysis of closely related species, speciation and phylogeography is the identification of variable sequence markers that allow the determination of genealogical relationships in multiple genomic regions using coalescent and species tree approaches. Rodent species represent nearly half of the mammalian diversity, but so far no systematic study has been carried out to detect suitable informative markers for this group. Here, we used a bioinformatic pipeline to extract intron sequences from rodent genomes available in databases and applied a series of filters that allowed the identification of 208 introns that adequately fulfilled several criteria for these studies. The main required characteristics of the introns were that they had the maximum possible mutation rates, that they were part of single-copy genes, that they had an appropriate sequence length for amplification, and that they were flanked by exons with suitable regions for primer design. In addition, in order to determine the validity of this approach, we chose ten of these introns for primer design and tested them in a panel of eleven rodent species belonging to different representative families. We show that all these introns can be amplified in the majority of species and that, overall, 79% of the amplifications worked with minimum optimization of the annealing temperature. In addition, we confirmed for a pair of sister species the relatively high level of sequence divergence of these introns. Therefore, we provide here a set of adequate intron markers that can be applied to different species of Rodentia for their use in studies that require significant sequence variability. PMID:24804779

Rodríguez-Prieto, Ana; Igea, Javier; Castresana, Jose

2014-01-01

391

Adaptive evolution of the matrix extracellular phosphoglycoprotein in mammals  

PubMed Central

Background Matrix extracellular phosphoglycoprotein (MEPE) belongs to a family of small integrin-binding ligand N-linked glycoproteins (SIBLINGs) that play a key role in skeleton development, particularly in mineralization, phosphate regulation and osteogenesis. MEPE associated disorders cause various physiological effects, such as loss of bone mass, tumors and disruption of renal function (hypophosphatemia). The study of this developmental gene from an evolutionary perspective could provide valuable insights on the adaptive diversification of morphological phenotypes in vertebrates. Results Here we studied the adaptive evolution of the MEPE gene in 26 Eutherian mammals and three birds. The comparative genomic analyses revealed a high degree of evolutionary conservation of some coding and non-coding regions of the MEPE gene across mammals indicating a possible regulatory or functional role likely related with mineralization and/or phosphate regulation. However, the majority of the coding region had a fast evolutionary rate, particularly within the largest exon (1467 bp). Rodentia and Scandentia had distinct substitution rates with an increased accumulation of both synonymous and non-synonymous mutations compared with other mammalian lineages. Characteristics of the gene (e.g. biochemical, evolutionary rate, and intronic conservation) differed greatly among lineages of the eight mammalian orders. We identified 20 sites with significant positive selection signatures (codon and protein level) outside the main regulatory motifs (dentonin and ASARM) suggestive of an adaptive role. Conversely, we find three sites under selection in the signal peptide and one in the ASARM motif that were supported by at least one selection model. The MEPE protein tends to accumulate amino acids promoting disorder and potential phosphorylation targets. Conclusion MEPE shows a high number of selection signatures, revealing the crucial role of positive selection in the evolution of this SIBLING member. The selection signatures were found mainly outside the functional motifs, reinforcing the idea that other regions outside the dentonin and the ASARM might be crucial for the function of the protein and future studies should be undertaken to understand its importance. PMID:22103247

2011-01-01

392

Updated neuronal scaling rules for the brains of Glires (rodents/lagomorphs).  

PubMed

Brain size scales as different functions of its number of neurons across mammalian orders such as rodents, primates, and insectivores. In rodents, we have previously shown that, across a sample of 6 species, from mouse to capybara, the cerebral cortex, cerebellum and the remaining brain structures increase in size faster than they gain neurons, with an accompanying decrease in neuronal density in these structures [Herculano-Houzel et al.: Proc Natl Acad Sci USA 2006;103:12138-12143]. Important remaining questions are whether such neuronal scaling rules within an order apply equally to all pertaining species, and whether they extend to closely related taxa. Here, we examine whether 4 other species of Rodentia, as well as the closely related rabbit (Lagomorpha), conform to the scaling rules identified previously for rodents. We report the updated neuronal scaling rules obtained for the average values of each species in a way that is directly comparable to the scaling rules that apply to primates [Gabi et al.: Brain Behav Evol 2010;76:32-44], and examine whether the scaling relationships are affected when phylogenetic relatedness in the dataset is accounted for. We have found that the brains of the spiny rat, squirrel, prairie dog and rabbit conform to the neuronal scaling rules that apply to the previous sample of rodents. The conformity to the previous rules of the new set of species, which includes the rabbit, suggests that the cellular scaling rules we have identified apply to rodents in general, and probably to Glires as a whole (rodents/lagomorphs), with one notable exception: the naked mole-rat brain is apparently an outlier, with only about half of the neurons expected from its brain size in its cerebral cortex and cerebellum. PMID:21985803

Herculano-Houzel, Suzana; Ribeiro, Pedro; Campos, Leandro; Valotta da Silva, Alexandre; Torres, Laila B; Catania, Kenneth C; Kaas, Jon H

2011-01-01

393

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

PubMed Central

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 highlights the need for further study to understand what maintains the observed morphological patterns. The work also indicates that mechanisms other than processes linked to local ecological specialization as a driver of diversification may contribute to the high diversity of this tropical region. PMID:23899319

2013-01-01

394

Expensive Brains: “Brainy” Rodents have Higher Metabolic Rate  

PubMed Central

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

Sobrero, Raúl; May-Collado, Laura J.; Agnarsson, Ingi; Hernández, Cristián E.

2011-01-01

395

Bot fly parasitism (Rogenhofera bonaerensis) (Diptera, Cuterebridae) in the pampean grassland mouse (Akodon azarae), in Argentina.  

PubMed

Seasonality and impact of parasitism by the larvae of Rogenhofera bonaerensis (Diptera: Cuterebridae) in pampean grassland mouse (Akodon azarae, Rodentia, Cricetidae) populations were studied in grasslands and cropfield borders near Diego Gaynor (Buenos Aires Province, Argentina), from November 1985 to December 1986. Trapped mice infections ranged from one larva (77%) to four (4%) per host; larvae occurred on tails (75.7%), backs (17.1%), thighs (5.7%), and abdomen (1.4%). Prevalence of larvae occurred in late spring (November and December) (35%), and in fall (March to June) (20%), with a peak of 25% during April and May. In spring these larvae affected 46% of resident and 19% of transient individuals; however, no differences were found between residents and transients in spring or fall. There was no significant relationship between mouse population density and prevalence of parasitism (r = -0.56). The annual percentage of infected rodents changed with age (body size classes): adults (37%) greater than subadults (25%) greater than juveniles (16%); with no differences between the sexes. Similar results were recorded in the spring, but there were no differences in the fall. Significant differences were not detected between stable (22% infected) and disturbed habitats (14% infected). During winter uninfected mice survived better than those infected during the previous fall. In contrast, the summer survival among spring infected mice and noninfected mice was similar. Parasitism showed no effects on reproductive activity and on home range size. Larvae showed strong host specificity for A. azarae (99%). Only one case was recorded in the long-tailed mouse (Oligoryzomys flavescens), and none in the white paunch mouse (Calomys laucha), both species sympatric with A. azarae.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2406466

Zuleta, G A; Vignau, M L

1990-01-01

396

The evolutionary radiation of Arvicolinae rodents (voles and lemmings): relative contribution of nuclear and mitochondrial DNA phylogenies  

PubMed Central

Background Mitochondrial and nuclear genes have generally been employed for different purposes in molecular systematics, the former to resolve relationships within recently evolved groups and the latter to investigate phylogenies at a deeper level. In the case of rapid and recent evolutionary radiations, mitochondrial genes like cytochrome b (CYB) are often inefficient for resolving phylogenetic relationships. One of the best examples is illustrated by Arvicolinae rodents (Rodentia; Muridae), the most impressive mammalian radiation of the Northern Hemisphere which produced voles, lemmings and muskrats. Here, we compare the relative contribution of a nuclear marker – the exon 10 of the growth hormone receptor (GHR) gene – to the one of the mitochondrial CYB for inferring phylogenetic relationships among the major lineages of arvicoline rodents. Results The analysis of GHR sequences improves the overall resolution of the Arvicolinae phylogeny. Our results show that the Caucasian long-clawed vole (Prometheomys schaposnikowi) is one of the basalmost arvicolines, and confirm that true lemmings (Lemmus) and collared lemmings (Dicrostonyx) are not closely related as suggested by morphology. Red-backed voles (Myodini) are found as the sister-group of a clade encompassing water vole (Arvicola), snow vole (Chionomys), and meadow voles (Microtus and allies). Within the latter, no support is recovered for the generic recognition of Blanfordimys, Lasiopodomys, Neodon, and Phaiomys as suggested by morphology. Comparisons of parameter estimates for branch lengths, base composition, among sites rate heterogeneity, and GTR relative substitution rates indicate that CYB sequences consistently exhibit more heterogeneity among codon positions than GHR. By analyzing the contribution of each codon position to node resolution, we show that the apparent higher efficiency of GHR is due to their third positions. Although we focus on speciation events spanning the last 10 million years (Myr), CYB sequences display highly saturated codon positions contrary to the nuclear exon. Lastly, variable length bootstrap predicts a significant increase in resolution of arvicoline phylogeny through the sequencing of nuclear data in an order of magnitude three to five times greater than the size of GHR exon 10. Conclusion Our survey provides a first resolved gene tree for Arvicolinae. The comparison of CYB and GHR phylogenetic efficiency supports recent assertions that nuclear genes are useful for resolving relationships of recently evolved animals. The superiority of nuclear exons may reside both in (i) less heterogeneity among sites, and (ii) the presence of highly informative sites in third codon positions, that evolve rapidly enough to accumulate synapomorphies, but slow enough to avoid substitutional saturation. PMID:17029633

Galewski, Thomas; Tilak, Marie-ka; Sanchez, Sophie; Chevret, Pascale; Paradis, Emmanuel; Douzery, Emmanuel JP

2006-01-01

397

The diversity of class II transposable elements in mammalian genomes has arisen from ancestral phylogenetic splits during ancient waves of proliferation through the genome.  

PubMed

DNA transposons make up 3% of the human genome, approximately the same percentage as genes. However, because of their inactivity, they are often ignored in favor of the more abundant, active, retroelements. Despite this relative ignominy, there are a number of interesting questions to be asked of these transposon families. One particular question relates to the timing of proliferation and inactivation of elements in a family. Does an ongoing process of turnover occur, or is the process more akin to a life cycle for the family, with elements proliferating rapidly before deactivation at a later date? We answer this question by tracing back to the most recent common ancestor (MRCA) of each modern transposon family, using two different methods. The first method identifies the MRCA of the species in which a family of transposon fossils can still be found, which we assume will have existed soon after the true origin date of the transposon family. The second method uses molecular dating techniques to predict the age of the MRCA element from which all elements found in a modern genome are descended. Independent data from five pairs of species are used in the molecular dating analysis: human-chimpanzee, human-orangutan, dog-panda, dog-cat, and cow-pig. Orthologous pairs of elements from host species pairs are included, and the divergence dates of these species are used to constrain the analysis. We discover that, in general, the times to element common ancestry for a given family are the same for the different species pairs, suggesting that there has been no order-specific process of turnover. Furthermore, for most families, the ages of the common ancestor of the host species and of that of the elements are similar, suggesting a life cycle model for the proliferation of transposons. Where these two ages differ, in families found only in Primates and Rodentia, for example, we find that the host species date is later than that of the common ancestor of the elements, implying that there may be large deletions of elements from host species, examples of which were found in their ancestors. PMID:22923465

Hellen, Elizabeth H B; Brookfield, John F Y

2013-01-01

398

Hantaan Virus Surveillance Targeting Small Mammals at Nightmare Range, a High Elevation Military Training Area, Gyeonggi Province, Republic of Korea  

PubMed Central

Rodent-borne disease surveillance was conducted at Nightmare Range (NM-R), near the demilitarized zone in northeast Gyeonggi Province, Republic of Korea, to identify hemorrhagic fever with renal syndrome (HFRS) risks for a mountainous high-elevation (500 m) military training site. Monthly surveys were conducted from January 2008-December 2009. A total of 1,720 small mammals were captured belonging to the Orders Rodentia [Families, Sciuridae (1 species) and Muridae (7 species)] and Soricomorpha [Family, Soricidae (1species)]. Apodemus agrarius, the primary reservoir for Hantaan virus (HTNV), accounted for 89.9% (1,546) of all small mammals captured, followed by Myodes regulus (4.0%), Crocidura lasiura (3.9%), Micromys minutus (1.4%), Mus musculus (0.3%), Microtus fortis (0.2%), Apodemus peninsulae (0.2%), Tamias sibiricus (0.1%), and Rattus norvegicus (<0.1%). Three species were antibody-positive (Ab+) for hantaviruses: A. agrarius (8.2%), M. minutus (4.2%), and C. lasiura (1.5%). HTNV specific RNA was detected in 93/127 Ab+ A. agrarius, while Imjin virus specific RNA was detected in 1/1 Ab+ C. lasiura. Overall, hantavirus Ab+ rates for A. agrarius increased with weight (age) and were significantly higher among males (10.9%) than females (5.1%) (P<0.0001). High A. agrarius gravid rates during the fall (August-September) were associated with peak numbers of HFRS cases in Korea that followed high gravid rates. From 79 RT-PCR positive A. agrarius, 12 HTNV RNA samples were sequenced and compared phylogenetically based on a 320 nt sequence from the GC glycoprotein-encoding M segment. These results demonstrate that the HTNV isolates from NM-R are distinctly separated from HTNV isolated from the People’s Republic of China. These studies provide for improved disease risk assessments that identify military activities, rodent HTNV rates, and other factors associated with the transmission of hantaviruses during field training exercises. PMID:25874643

Klein, Terry A.; Kim, Heung-Chul; Chong, Sung-Tae; Kim, Jeong-Ah; Lee, Sook-Young; Kim, Won-Keun; Nunn, Peter V.; Song, Jin-Won

2015-01-01

399

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

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 rather high. We observed no differences between cortisol concentration in experimental and control animals during the reproductive period in early spring and mid-summer. We tend to interpret the absence of geroprotective effect of SkQ1 on free-breeding dwarf hamsters by its ability to intensify breeding. We previously demonstrated the ability of SkQ1 to increase the lifespan of non-breeding females. PMID:25519070

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

2014-10-01

400

Hantaan virus surveillance targeting small mammals at nightmare range, a high elevation military training area, gyeonggi province, republic of Korea.  

PubMed

Rodent-borne disease surveillance was conducted at Nightmare Range (NM-R), near the demilitarized zone in northeast Gyeonggi Province, Republic of Korea, to identify hemorrhagic fever with renal syndrome (HFRS) risks for a mountainous high-elevation (500 m) military training site. Monthly surveys were conducted from January 2008-December 2009. A total of 1,720 small mammals were captured belonging to the Orders Rodentia [Families, Sciuridae (1 species) and Muridae (7 species)] and Soricomorpha [Family, Soricidae (1species)]. Apodemus agrarius, the primary reservoir for Hantaan virus (HTNV), accounted for 89.9% (1,546) of all small mammals captured, followed by Myodes regulus (4.0%), Crocidura lasiura (3.9%), Micromys minutus (1.4%), Mus musculus (0.3%), Microtus fortis (0.2%), Apodemus peninsulae (0.2%), Tamias sibiricus (0.1%), and Rattus norvegicus (<0.1%). Three species were antibody-positive (Ab+) for hantaviruses: A. agrarius (8.2%), M. minutus (4.2%), and C. lasiura (1.5%). HTNV specific RNA was detected in 93/127 Ab+ A. agrarius, while Imjin virus specific RNA was detected in 1/1 Ab+ C. lasiura. Overall, hantavirus Ab+ rates for A. agrarius increased with weight (age) and were significantly higher among males (10.9%) than females (5.1%) (P<0.0001). High A. agrarius gravid rates during the fall (August-September) were associated with peak numbers of HFRS cases in Korea that followed high gravid rates. From 79 RT-PCR positive A. agrarius, 12 HTNV RNA samples were sequenced and compared phylogenetically based on a 320 nt sequence from the GC glycoprotein-encoding M segment. These results demonstrate that the HTNV isolates from NM-R are distinctly separated from HTNV isolated from the People's Republic of China. These studies provide for improved disease risk assessments that identify military activities, rodent HTNV rates, and other factors associated with the transmission of hantaviruses during field training exercises. PMID:25874643

Klein, Terry A; Kim, Heung-Chul; Chong, Sung-Tae; Kim, Jeong-Ah; Lee, Sook-Young; Kim, Won-Keun; Nunn, Peter V; Song, Jin-Won

2015-01-01

401

Evidence for the use of reflected self-generated seismic waves for spatial orientation in a blind subterranean mammal.  

PubMed

Subterranean mammals like the blind mole-rat (Rodentia: Spalax ehrenbergi) are functionally blind and possess poor auditory sensitivity, limited to low-frequency sounds. Nevertheless, the mole-rat demonstrates extremely efficient ability to orient spatially. A previous field study has revealed that the mole-rat can assess the location, size and density of an underground obstacle, and accordingly excavates the most efficient bypass tunnel to detour around the obstacles. In the present study we used a multidisciplinary approach to examine the possibility that the mole-rat estimates the location and physical properties of underground obstacles using reflected self-generated seismic waves (seismic 'echolocation'). Our field observations revealed that all the monitored mole-rats produced low-frequency seismic waves (250-300 Hz) at intervals of 8+/-5 s (range: 1-13 s) between head drums while digging a bypass to detour an obstacle. Using a computerized simulation model we demonstrated that it is possible for the mole-rat to determine its distance from an obstacle boundary (open ditch or stone) by evaluating the amplitude (intensity) of the seismic wave reflected back to it from the obstacle interface. By evaluating the polarity of the reflected wave the mole-rat could distinguish between air space and solid obstacles. Further, the model showed that the diffracted waves from the obstacle's corners could give the mole-rat precise information on the obstacle size and its relative spatial position. In a behavioural experiment using a special T-maze setup, we tested whether the mole-rat can perceive seismic waves through the somatosensory system and localize the source. The results revealed that the mole-rat is able to detect low frequency seismic waves using only its paws, and in most cases the mole-rats determined accurately the direction of the vibratory source. In a histological examination of the glabrous skin of the mole-rat's paws we identified lamellate corpuscle mechanoreceptors that might be used to detect low frequency seismic waves. The combined findings from these different approaches lead us to suggest that a specialized seismic 'echolocation' system could be used by subterranean mammals to determine the most energy-conserving strategy with which to bypass an obstacle, as well as to estimate their distance from the surface, keeping their tunnels at the optimal depth. PMID:15695757

Kimchi, Tali; Reshef, Moshe; Terkel, Joseph

2005-02-01

402

A New Approach to Testing the Fossorial Rodent Hypothesis of Mima Mound Formation Using Airborne-Based LIDAR and a Diffusive Sediment Transport Model  

NASA Astrophysics Data System (ADS)

Mima mounds are nearly circular soil mounds, found in grassland landscapes. In California, Mima mounds are often associated with vernal pools, seasonal wetlands that harbor rare and endemic plants and animals. The processes that form and maintain the mound-pool complexes have not yet been conclusively identified, even though such information is necessary to understand the effects that land use and climate change may have on the resilience and longevity of these landscapes. One hypothesis for the origin and persistence of Mima mound- vernal pool systems (termed the Fossorial Rodent Hypothesis) proposes that burrowing organisms such as pocket gophers (Rodentia: Geomyidae) maintain and possibly create the mounds by preferentially translocating soils towards mound centers as an adaptive response to high water tables. In order to investigate this hypothesis, the topographic characteristics and aboveground gopher activity of one of the largest remaining Mima mound-vernal pool systems in California were studied. Detailed topographic information for the mound-pool systems was obtained via an airborne-based LIDAR (Light Detection and Ranging) survey of a 25km2 region near Merced, CA. An object-oriented classification scheme, which combined different scale, shape, and spectral parameters, was employed in order to characterize the mounds. Based on the initial classification results, roughly 275,000 mounds were identified, indicating a mound density of 11,000km-2. Within the larger study area, gopher sediment transport was monitored on a 3507m2 site by conducting periodic surveys of sediment mounds created by gopher activity using a Global Positioning System and mass measurements. Downslope erosion rates (off Mima mounds) were estimated using a mass balance model which incorporates a diffusive sediment transport law. The median calculated net downslope erosion rate was 15 cm of soil per 1000 years, while the measured rate of aboveground gopher sediment movement was approximately 57cm of soil per 1000 years. Assuming that some portion of the gopher sediment movement is in an upslope direction, these results suggest that gopher soil transport may be large enough to compensate for erosion, and this activity may play a dominant role in maintaining Mima mound-vernal pool systems. The results of this study were used to guide the development of a quantitative model of gopher-driven sediment transport on Mima mound-vernal pool landscapes. This model will be used to infer the origin of the landscapes and the rates of processes critical to their continued functioning and will also help to determine, quantitatively, the role of burrowing animals as a "keystone" species on these landscapes.

Reed, S. E.; Amundson, R.

2007-12-01

403

Evolution of alanine:glyoxylate aminotransferase 1 peroxisomal and mitochondrial targeting. A survey of its subcellular distribution in the livers of various representatives of the classes Mammalia, Aves and Amphibia.  

PubMed

As part of a wider study on the molecular evolution of alanine:glyoxylate aminotransferase 1 (AGT1) intracellular compartmentalization, we have determined the subcellular distribution of immunoreactive AGT1, using postembedding protein A-gold immunoelectron microscopy, in the livers of various members of the classes Mammalia, Aves, and Amphibia. As far as organellar distribution is concerned, three categories could be distinguished. In members of the first category (type I), all, or nearly all, of the immunoreactive AGT1 was concentrated within the peroxisomes. In the second category (type II), AGT1 was found more evenly distributed in both peroxisomes and mitochondria. In the third category (type III), AGT1 was localized mainly within the mitochondria with much lower, but widely variable, amounts in the peroxisomes. Type I animals include the human, two great apes (gorilla, orangutan), two Old World monkeys (anubis baboon, Japanese macaque), a New World monkey (white-faced Saki monkey), a lago, morph (European rabbit), a bat (Seba's short-tailed fruit bat), two caviomorph rodents (guinea pig, orange-rumped agouti), and two Australian marsupials (koala, Bennett's wallaby). Type II animals include two New World monkeys (common marmoset, cotton-top tamarin), three prosimians (brown lemur, fat-tailed dwarf lemur, pygmy slow loris), five rodents (a hybrid crested porcupine, Colombian ground squirrel, laboratory rat, laboratory mouse, golden hamster), an American marsupial (grey short-tailed opossum), and a bird (raven). Type III animals include the large tree shrew, three insectivores (common Eurasian mole, European hedgehog, house shrew), four carnivores (domestic cat, ocelot, domestic dog, polecat ferret), and an amphibian (common frog). In addition to these categories, some animals (e.g. guinea pig, common frog) possessed significant amounts of cytosolic AGT1. Whereas the subcellular distribution of AGT1 in some orders (e.g. Insectivora and Carnivora) did not appear to vary markedly between the different members, in other orders (e.g. Primates, Rodentia and Marsupialia) it fluctuated widely between the different species. Phylogenetic analysis indicates that the subcellular distribution of AGT1 has changed radically on numerous occasions during the evolution of mammals. The new observations presented in this paper are compatible with our previous demonstration of a relationship between AGT1 subcellular distribution and either present or putative ancestral dietary habit, and our previous suggestion that the molecular evolution of the AGT gene has been markedly influenced by dietary selection pressure. PMID:7813517

Danpure, C J; Fryer, P; Jennings, P R; Allsop, J; Griffiths, S; Cunningham, A

1994-08-01

404

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

PubMed Central

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

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

2015-01-01

405

Evolution of spatially coexpressed families of type-2 vomeronasal receptors in rodents.  

PubMed

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

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

2015-01-01

406

Chagas disease: control, elimination and eradication. Is it possible?  

PubMed Central

From an epidemiological point of view, Chagas disease and its reservoirs and vectors can present the following characteristics: (i) enzooty, maintained by wild animals and vectors, with broad occurrence from southern United States of America (USA) to southern Argentina and Chile (42ºN 49ºS), (ii) anthropozoonosis, when man invades the wild ecotope and becomes infected with Trypanosoma cruzi from wild animals or vectors or when the vectors and wild animals, especially marsupials, invade the human domicile and infect man, (iii) zoonosis-amphixenosis and exchanged infection between animals and humans by domestic vectors in endemic areas and (iv) zooanthroponosis, infection that is transmitted from man to animals, by means of domestic vectors, which is the rarest situation in areas endemic for Chagas disease. The characteristics of Chagas disease as an enzooty of wild animals and as an anthropozoonosis are seen most frequently in the Brazilian Amazon and in the Pan-Amazon region as a whole, where there are 33 species of six genera of wild animals: Marsupialia, Chiroptera, Rodentia, Edentata (Xenarthra), Carnivora and Primata and 27 species of triatomines, most of which infected with T. cruzi . These conditions place the resident populations of this area or its visitors - tourists, hunters, fishermen and especially the people whose livelihood involves plant extraction - at risk of being affected by Chagas disease. On the other hand, there has been an exponential increase in the acute cases of Chagas disease in that region through oral transmission of T. cruzi , causing outbreaks of the disease. In four seroepidemiological surveys that were carried out in areas of the microregion of the Negro River, state of Amazonas, in 1991, 1993, 1997 and 2010, we found large numbers of people who were serologically positive for T. cruzi infection. The majority of them and/or their relatives worked in piassava extraction and had come into contact with and were stung by wild triatomines in that area. Finally, a characteristic that is greatly in evidence currently is the migration of people with Chagas disease from endemic areas of Latin America to non-endemic countries. This has created a new dilemma for these countries: the risk of transmission through blood transfusion and the onus of controlling donors and treating migrants with the disease. As an enzooty of wild animals and vectors, and as an anthropozoonosis, Chagas disease cannot be eradicated, but it must be controlled by transmission elimination to man. PMID:24402148

Coura, José Rodrigues

2013-01-01

407

Chagas disease: control, elimination and eradication. Is it possible?  

PubMed

From an epidemiological point of view, Chagas disease and its reservoirs and vectors can present the following characteristics: (i) enzooty, maintained by wild animals and vectors, with broad occurrence from southern United States of America (USA) to southern Argentina and Chile (42ºN 49ºS), (ii) anthropozoonosis, when man invades the wild ecotope and becomes infected with Trypanosoma cruzi from wild animals or vectors or when the vectors and wild animals, especially marsupials, invade the human domicile and infect man, (iii) zoonosis-amphixenosis and exchanged infection between animals and humans by domestic vectors in endemic areas and (iv) zooanthroponosis, infection that is transmitted from man to animals, by means of domestic vectors, which is the rarest situation in areas endemic for Chagas disease. The characteristics of Chagas disease as an enzooty of wild animals and as an anthropozoonosis are seen most frequently in the Brazilian Amazon and in the Pan-Amazon region as a whole, where there are 33 species of six genera of wild animals: Marsupialia, Chiroptera, Rodentia, Edentata (Xenarthra), Carnivora and Primata and 27 species of triatomines, most of which infected with T. cruzi . These conditions place the resident populations of this area or its visitors - tourists, hunters, fishermen and especially the people whose livelihood involves plant extraction - at risk of being affected by Chagas disease. On the other hand, there has been an exponential increase in the acute cases of Chagas disease in that region through oral transmission of T. cruzi , causing outbreaks of the disease. In four seroepidemiological surveys that were carried out in areas of the microregion of the Negro River, state of Amazonas, in 1991, 1993, 1997 and 2010, we found large numbers of people who were serologically positive for T. cruzi infection. The majority of them and/or their relatives worked in piassava extraction and had come into contact with and were stung by wild triatomines in that area. Finally, a characteristic that is greatly in evidence currently is the migration of people with Chagas disease from endemic areas of Latin America to non-endemic countries. This has created a new dilemma for these countries: the risk of transmission through blood transfusion and the onus of controlling donors and treating migrants with the disease. As an enzooty of wild animals and vectors, and as an anthropozoonosis, Chagas disease cannot be eradicated, but it must be controlled by transmission elimination to man. PMID:24402148

Coura, José Rodrigues

2013-12-01

408

Highly Diverse Morbillivirus-Related Paramyxoviruses in Wild Fauna of the Southwestern Indian Ocean Islands: Evidence of Exchange between Introduced and Endemic Small Mammals  

PubMed Central

ABSTRACT The Paramyxoviridae form an increasingly diverse viral family, infecting a wide variety of different hosts. In recent years, they have been linked to disease emergence in many different animal populations and in humans. Bats and rodents have been identified as major animal populations capable of harboring paramyxoviruses, and host shifting between these animals is likely to be an important driving factor in the underlying evolutionary processes that eventually lead to disease emergence. Here, we have studied paramyxovirus circulation within populations of endemic and introduced wild small mammals of the southwestern Indian Ocean region and belonging to four taxonomic orders: Rodentia, Afrosoricida, Soricomorpha, and Chiroptera. We report elevated infection levels as well as widespread paramyxovirus dispersal and frequent host exchange of a newly emerging genus of the Paramyxoviridae, currently referred to as the unclassified morbillivirus-related viruses (UMRVs). In contrast to other genera of the Paramyxoviridae, where bats have been shown to be a key host species, we show that rodents (and, in particular, Rattus rattus) are significant spreaders of UMRVs. We predict that the ecological particularities of the southwestern Indian Ocean, where small mammal species often live in densely packed, multispecies communities, in combination with the increasing invasion of R. rattus and perturbations of endemic animal communities by active anthropological development, will have a major influence on the dynamics of UMRV infection. IMPORTANCE Identification of the infectious agents that circulate within wild animal reservoirs is essential for several reasons: (i) infectious disease outbreaks often originate from wild fauna; (ii) anthropological expansion increases the risk of contact between human and animal populations and, as a result, the risk of disease emergence; (iii) evaluation of pathogen reservoirs helps in elaborating preventive measures to limit the risk of disease emergence. Many paramyxoviruses for which bats and rodents serve as major reservoirs have demonstrated their potential to cause disease in humans and animals. In the context of the biodiversity hot spot of southwestern Indian Ocean islands and their rich endemic fauna, we show that highly diverse UMRVs exchange between various endemic animal species, and their dissemination likely is facilitated by the introduced Rattus rattus. Hence, many members of the Paramyxoviridae appear well adapted for the study of the viral phylodynamics that may be associated with disease emergence. PMID:24829336

Mélade, Julien; Dietrich, Muriel; Ramasindrazana, Beza; Soarimalala, Voahangy; Lagadec, Erwan; le Minter, Gildas; Tortosa, Pablo; Heraud, Jean-Michel; de Lamballerie, Xavier; Goodman, Steven M.; Dellagi, Koussay

2014-01-01

409

Morphological peculiarities of the deep infratemporal fossa in advanced age.  

PubMed

The main osseous landmarks of the border area between the infratemporal fossa and the para- and retro pharyngeal space are the sphenoidal spine and the pterygoid and styloid processes, and the styloid vagina. These landmarks, as well as some vascular anomalies, were studied in order to illustrate the variable anatomy, which is encountered in the surgical lateral transzygomatic infratemporal fossa approach. Hundred well-preserved human skull bases were examined. The deep infratemporal fossa was dissected into 54 halves of fixed cadaveric head and neck specimens of both sexes. Dry skull specimens of New and Old World monkeys, skulls of rodents, herbivora and carnivora, and computed tomograms of the head of Macaca fuscata Japonica, were also studied. In 91 of the human skull bases, the sphenoidal spine was prominent and well developed. In three skulls, the spine was absent. In four specimens, however, the spine was not sphenoidal but a part of the temporal bone, occurring in the form of a process, which emanated from the styloid vagina. In two further cases, there was unilaterally a duplicated spine; the anterior part represented a regular sphenoidal spine, while the posterior part constituted a part of the vagina of the styloid process. A complete osseous bar, arch or lamina-connecting the posterior border of the lateral lamina of the pterygoid process and the sphenoidal spine-existed in six of the human dry skulls. In ten of the human skulls examined, the breadth of the lateral lamina of the pterygoid process was greater than 10 mm; thus, the so-called pterygospinous (ps) and the pterygostyloid gates-of significance where surgical approaches are concerned-were less than 10 mm in width. Fibrous or muscular connections were also found in some cadaveric specimens between the posterior border of the lateral lamina of the pterygoid process and the sphenoidal spine: a ps ligament existed in 11 cases (20.4%) and a ps muscle in 5 cases (9.2 %), in 3 of which it inserted into both the medial wall capsule and the articular disc of the temporo-mandibular joint. Among the cadaveric specimens exhibiting ps structures was one in which an osseous ps bar occurred together with a ps muscle; in two cases a strong ps ligament was observed together with a ps muscle. The distribution pattern of the mandibular nerve was affected by the positioning of the ps bar, ligament and muscle when the latter were present. The existence of a wide ps bar was noted in all the skulls of herbivora, rodentia, carnivora, and Old World monkeys that were examined, but never in those of the New World monkeys; it is likely that, in the human, this ps bar represents a phylogenetic remnant. In the human dry skull specimens and cadaveric material, the ps ligament was found to be a reinforcement of the interpterygoid fascia, and the ps muscle to be a third head of the lateral pterygoid muscle. In two cases, the internal carotid artery exhibited a significant elongation and space-consuming tortuosity (so-called coiling behavior) in the depth of the infratemporal fossa. PMID:16470343

von Lüdinghausen, Michael; Kageyama, Ikuo; Miura, Masahiro; Alkhatib, Mohamed

2006-06-01