Postglacial species displacement in Triturus newts deduced from asymmetrically introgressed mitochondrial DNA and ecological niche models.

PubMed

Wielstra, Ben; Arntzen, Jan W

2012-08-30

If the geographical displacement of one species by another is accompanied by hybridization, mitochondrial DNA can introgress asymmetrically, from the outcompeted species into the invading species, over a large area. We explore this phenomenon using the two parapatric crested newt species, Triturus macedonicus and T. karelinii, distributed on the Balkan Peninsula in south-eastern Europe, as a model. We first delimit a ca. 54,000 km(2) area in which T. macedonicus contains T. karelinii mitochondrial DNA. This introgression zone bisects the range of T. karelinii, cutting off a T. karelinii enclave. The high similarity of introgressed mitochondrial DNA haplotypes with those found in T. karelinii suggests a recent transfer across the species boundary. We then use ecological niche modeling to explore habitat suitability of the location of the present day introgression zone under current, mid-Holocene and Last Glacial Maximum conditions. This area was inhospitable during the Last Glacial Maximum for both species, but would have been habitable at the mid-Holocene. Since the mid-Holocene, habitat suitability generally increased for T. macedonicus, whereas it decreased for T. karelinii. The presence of a T. karelinii enclave suggests that T. karelinii was the first to colonize the area where the present day introgression zone is positioned after the Last Glacial Maximum. Subsequently, we propose T. karelinii was outcompeted by T. macedonicus, which captured T. karelinii mitochondrial DNA via introgressive hybridization in the process. Ecological niche modeling suggests that this replacement was likely facilitated by a shift in climate since the mid-Holocene. We suggest that the northwestern part of the current introgression zone was probably never inhabited by T. karelinii itself, and that T. karelinii mitochondrial DNA spread there through T. macedonicus exclusively. Considering the spatial distribution of the introgressed mitochondrial DNA and the signal derived from ecological niche modeling, we do not favor the hypothesis that foreign mitochondrial DNA was pulled into the T. macedonicus range by natural selection.

Isolation and Characterization of Viruses from the Kidneys of Rana pipiens with Renal Adenocarcinoma Before and After Passage in the Red Eft (Triturus viridescens)

PubMed Central

Clark, H. Fred; Brennan, James C.; Zeigel, Robert F.; Karzon, David T.

1968-01-01

Viruses were isolated from kidneys of normal and renal tumor-bearing Vermont Rana pipiens after subinoculation into red eft newts (Triturus viridescens). Organs of efts inoculated with viable cell suspensions from four of seven tumor-bearing kidneys yielded virus (LT-1, -2, -3, -4) when inoculated into TH-1 (Terrapene heart) cell culture. One tumor-bearing kidney also yielded virus (L-4) by direct inoculation into TH-1 cells. An additional isolate (L-5) was obtained from 1 of 52 normal Vermont frog kidneys inoculated directly into TH-1 cells. LT-1 was propagated with cytopathic effect (CPE) in each of 38 cell types tested, of fish, amphibian, reptilian, avian, and mammalian origin, at 23 or 30 C. LT-1 through LT-4, L-4 and L-5, and FV-1 through FV-3 each induced similar CPE in all cells tested. LT-2, however, induced CPE that progressed at a slower rate than that caused by the other isolates and produced smaller plaques (<0.8 mm) under starch gel overlay. Each of the viruses replicated to high titer in embryonated eggs incubated at 30 C. The viruses also grew in efts and adult newts, but not in bullfrog (Rana catesbeiana) tadpoles or adult leopard frogs. Tumor induction in adult leopard frogs inoculated with LT-1 was not demonstrated. Electron microscopic observations of LT-1 and LT-2 viruses revealed cytoplasmic particles, hexagonal in cross section, approximately 120 to 140 mμ in diameter, containing a dense nucleoid. LT-1 and LT-2 viruses were indistinguishable from FV-1 and Tipula iridescent virus. LT-1 was presumed to be a deoxyribonucleic acid virus on the basis of 5-bromodeoxyuridine inhibition. The isolates were ether-sensitive. On the basis of biological, physicochemical, and antigenic similarities, LT-1 through LT-4, L-4, L-5, FV-1 through FV-3, and isolates recently recovered from the bullfrog and the newt may represent strains of the same amphibian cytoplasmic virus. Images PMID:4972302

Amphibian recovery after a decrease in acidic precipitation.

PubMed

Dolmen, Dag; Finstad, Anders Gravbrøt; Skei, Jon Kristian

2018-04-01

We here report the first sign of amphibian recovery after a strong decline due to acidic precipitation over many decades and peaking around 1980-90. In 2010, the pH level of ponds and small lakes in two heavily acidified areas in southwestern Scandinavia (Aust-Agder and Østfold in Norway) had risen significantly at an (arithmetic) average of 0.14 since 1988-89. Parallel with the general rise in pH, amphibians (Rana temporaria, R. arvalis, Bufo bufo, Lissotriton vulgaris, and Triturus cristatus) had become significantly more common: the frequency of amphibian localities rose from 33% to 49% (n = 115), and the average number of amphibian species per locality had risen from 0.51 to 0.88. In two other (reference) areas, one with better buffering capacity (Telemark, n = 21) and the other with much less input of acidic precipitation (Nord-Trøndelag, n = 106), there were no significant changes in pH or amphibians.

Exploring the effect of asymmetric mitochondrial DNA introgression on estimating niche divergence in morphologically cryptic species.

PubMed

Wielstra, Ben; Arntzen, Jan W

2014-01-01

If potential morphologically cryptic species, identified based on differentiated mitochondrial DNA, express ecological divergence, this increases support for their treatment as distinct species. However, mitochondrial DNA introgression hampers the correct estimation of ecological divergence. We test the hypothesis that estimated niche divergence differs when considering nuclear DNA composition or mitochondrial DNA type as representing the true species range. We use empirical data of two crested newt species (Amphibia: Triturus) which possess introgressed mitochondrial DNA from a third species in part of their ranges. We analyze the data in environmental space by determining Fisher distances in a principal component analysis and in geographical space by determining geographical overlap of species distribution models. We find that under mtDNA guidance in one of the two study cases niche divergence is overestimated, whereas in the other it is underestimated. In the light of our results we discuss the role of estimated niche divergence in species delineation.

The ontogenetic origins of skull shape disparity in the Triturus cristatus group.

PubMed

Cvijanović, Milena; Ivanović, Ana; Kalezić, Miloš L; Zelditch, Miriam L

2014-09-01

Comparative studies of ontogenies of closely related species provide insights into the mechanisms responsible for morphological diversification. Using geometric morphometrics, we investigated the ontogenetic dynamics of postlarval skull shape and disparity in three closely related crested newt species. The skull shapes of juveniles just after metamorphosis (hereafter metamorphs) and adult individuals were sampled by landmark configurations that describe the shape of the dorsal and ventral side of the newt skull, and analyzed separately. The three species differ in skull size and shape in metamorphs and adults. The ontogenies of dorsal and ventral skull differ in the orientation but not lengths of the ontogenetic trajectories. The disparity of dorsal skull shape increases over ontogeny, but that of ventral skull shape does not. Thus, modifications of ontogenetic trajectories can, but need not, increase the disparity of shape. In species with biphasic life-cycles, when ontogenetic trajectories for one stage can be decoupled from those of another, increases and decreases in disparity are feasible, but our results show that they need not occur. © 2014 Wiley Periodicals, Inc.

Seasonal variation in environmental DNA in relation to population size and environmental factors

PubMed Central

Buxton, Andrew S.; Groombridge, Jim J.; Zakaria, Nurulhuda B.; Griffiths, Richard A.

2017-01-01

Analysing DNA that organisms release into the environment (environmental DNA, or eDNA) has enormous potential for assessing rare and cryptic species. At present the method is only reliably used to assess the presence-absence of species in natural environments, as seasonal influences on eDNA in relation to presence, abundance, life stages and seasonal behaviours are poorly understood. A naturally colonised, replicated pond system was used to show how seasonal changes in eDNA were influenced by abundance of adults and larvae of great crested newts (Triturus cristatus). Peaks in eDNA were observed in early June when adult breeding was coming to an end, and between mid-July and mid-August corresponding to a peak in newt larval abundance. Changes in adult body condition associated with reproduction also influenced eDNA concentrations, as did temperature (but not rainfall or UV). eDNA concentration fell rapidly as larvae metamorphosed and left the ponds. eDNA concentration may therefore reflect relative abundance in different ponds, although environmental factors can affect the concentrations observed. Nevertheless, eDNA surveys may still represent an improvement over unadjusted counts which are widely used in population assessments but have unreliable relationships with population size. PMID:28393885

Species identification by conservation practitioners using online images: accuracy and agreement between experts.

PubMed

Austen, Gail E; Bindemann, Markus; Griffiths, Richard A; Roberts, David L

2018-01-01

Emerging technologies have led to an increase in species observations being recorded via digital images. Such visual records are easily shared, and are often uploaded to online communities when help is required to identify or validate species. Although this is common practice, little is known about the accuracy of species identification from such images. Using online images of newts that are native and non-native to the UK, this study asked holders of great crested newt ( Triturus cristatus ) licences (issued by UK authorities to permit surveying for this species) to sort these images into groups, and to assign species names to those groups. All of these experts identified the native species, but agreement among these participants was low, with some being cautious in committing to definitive identifications. Individuals' accuracy was also independent of both their experience and self-assessed ability. Furthermore, mean accuracy was not uniform across species (69-96%). These findings demonstrate the difficulty of accurate identification of newts from a single image, and that expert judgements are variable, even within the same knowledgeable community. We suggest that identification decisions should be made on multiple images and verified by more than one expert, which could improve the reliability of species data.

‘Monster… -omics’: on segmentation, re-segmentation, and vertebrae formation in amphibians and other vertebrates

PubMed Central

2013-01-01

Background The axial skeleton is one of the defining evolutionary landmarks of vertebrates. How this structure develops and how it has evolved in the different vertebrate lineages is, however, a matter of debate. Vertebrae and vertebral structures are derived from the embryonic somites, although the mechanisms of development are different between lineages. Discussion Using the anecdotal description of a teratological newt (Triturus dobrogicus) with an unusual malformation in its axial skeleton, we review, compare, and discuss the development of vertebral structures and, in particular, the development of centra from somitic cellular domains in different vertebrate groups. Vertebrae development through re-segmentation of the somitic sclerotomal cells is considered the general mechanism among vertebrates, which has been generalized from studies in amniotic model organisms. The prevalence of this mechanism among anamniotes is, however, controversial. We propose alternative developmental mechanisms for vertebrae formation that should be experimentally tested. Summary Research in model organisms, especially amniotes, is laying the foundations for a thorough understanding of the mechanisms of development of the axial skeleton in vertebrates, foundations that should expand the extent of future comparative studies. Although immersed in the ‘-omics’ era, we emphasize the need for an integrative and organismal approach in evolutionary developmental biology for a better understanding of the causal role of development in the evolution of morphological diversity in nature. PMID:23577917

Fossil amphibians and reptiles from Tegelen (Province of Limburg) and the early Pleistocene palaeoclimate of The Netherlands

NASA Astrophysics Data System (ADS)

Villa, Andrea; Blain, Hugues-Alexandre; van den Hoek Ostende, Lars W.; Delfino, Massimo

2018-05-01

Few Quaternary herpetofaunas have been recovered from The Netherlands. Among these, the one coming from the early Pleistocene site of the Russel-Tiglia-Egypte pit near Tegelen is of particular interest, because it is the type locality of the recently described, last western European palaeobatrachid anuran, Palaeobatrachus eurydices. The large number of fossil remains of amphibians and reptiles found in the pit are representative of a very diverse fauna, including at least 17 taxa: Triturus gr. T. cristatus, Lissotriton sp., Pelobates fuscus, Bufo bufo, Bombina sp., Pelophylax sp., Rana sp., Hyla gr. H. arborea, Pelodytes sp., Mauremys sp., Lacerta sp., Lacertidae indet., Anguis gr. A. fragilis, cf. Pseudopus sp., "colubrines" indet., Natrix natrix and Vipera sp. Emys orbicularis, previously reported from a different Tegelen pit, is not present in this assemblage. Palaeoclimatic conditions reconstructed based on the herpetofaunistic association indicate a humid subtropical climate (Cfa according to the Köppen-Geiger classification of climates) for Tegelen during the TC5 section of the Tiglian, with low, but fairly regular rainfalls during the year. Mean annual temperature was 13.4 ± 0.3 °C and mean annual precipitation was 542 ± 50 mm. Moreover, three dry months were present during summer and early autumn, resulting in a much drier climate than the one present at Tegelen today. Nevertheless, the occurrence of the water-dwelling P. eurydices suggests the persistence of suitable permanent water bodies during the whole year, and the survival of this taxon in this part of Europe might have been allowed by the generally humid climate.

Chromosomal DNA replication in higher plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van't Hof, J.; Bjerknes, C.A.

1979-01-01

Replicon-size estimations from DNA fiber autoradiograms must always be considered with the limits of resolution in mind. However, data from yeast obtained by autoradiography and electron-microscopy gave similar average sizes in the 20 to 30 ..mu..m range. These sizes are in agreement with those of C. capillaris observed in the present work, with those of Pisum sativum and Helianthus annuus, and with those of four other unrelated plant species. The curious fact that higher plants and yeast have replicons of about the same size raises the question of whether or not all members of the plant kingdom share this commonmore » statistic. Higher plants appear to have a common replicon size, and they also have a slower fork rate than either bacteria or mammalian cells when grown at optimal temperatures. Even at 38/sup 0/ sunflower (Helianthus annuus) root meristem cells have a fork rate a little less than 12 ..mu..m per hour. On the other hand, at about the same temperature, the rate is approximately 800 ..mu..m per hour in bacteria, and in mammalian cells it ranges from 30 to 60 ..mu..m per hour. Current data from higher plants show that they have a range in fork rate from 6 to 12 ..mu..m per hour. The lower rates observed among higher plants are similar to and more often less than those reported for the amphibians Triturus and Xenopus and that of fatheat minnow cells. Therefore, higher plants and cold-blooded animals commonly share the characteristic of a relatively low replication fork rate.« less

Morphological and immunohistochemical reactions of the larval epidermis in the Italian newt (Lissotriton italicus) after exposure to low pH.

PubMed

Brunelli, Elvira

2018-02-01

Mounting evidence suggests that amphibians are globally and currently the most threatened group of vertebrates and different causes might be responsible for this phenomenon. Acidification of water bodies is a global environmental issue that has been proposed as a possible cause for amphibian populations decline. Indeed, it has been widely demonstrated that low pH may exert harmful effects on amphibians, either directly or by increasing the adverse effects of other stressors. Surprisingly only few studies documented the response of amphibian integument to acidic pH conditions and no data are available on the effects of a non-lethal level of pH onto the amphibian larval epidermis. The present study showed that acidic pH (4.5) condition has severe effects on the epidermis of the Italian newt (Lissotriton italicus, formerly Triturus italicus) inducing both morphological and functional alterations. The increase of mucus is the first evident effect of acid injury, followed by the flattening of the epithelium and the appearance of a keratinized shedding layer. The immunolabeling of cytokeratins substantially changes acquiring an adult-like pattern. Also aquaporin 3 and iNOS expression modify their distribution according to a change of the histological features of the epidermis. These results clearly indicate that a short-term exposure to a sub-lethal pH disrupts the epidermis morphology and function in L. italicus larvae. Since the skin exerts a prominent role in both respiration and osmoregulation, the described alterations may adversely affect the overall ionic balance, with a long chain of cascading effects significantly decreasing newts survival probabilities when environmental pH lowering occurs. Copyright © 2018 Elsevier GmbH. All rights reserved.

Life history tactics shape amphibians' demographic responses to the North Atlantic Oscillation.

PubMed

Cayuela, Hugo; Joly, Pierre; Schmidt, Benedikt R; Pichenot, Julian; Bonnaire, Eric; Priol, Pauline; Peyronel, Olivier; Laville, Mathias; Besnard, Aurélien

2017-11-01

Over the last three decades, climate abnormalities have been reported to be involved in biodiversity decline by affecting population dynamics. A growing number of studies have shown that the North Atlantic Oscillation (NAO) influences the demographic parameters of a wide range of plant and animal taxa in different ways. Life history theory could help to understand these different demographic responses to the NAO. Indeed, theory states that the impact of weather variation on a species' demographic traits should depend on its position along the fast-slow continuum. In particular, it is expected that NAO would have a higher impact on recruitment than on adult survival in slow species, while the opposite pattern is expected occur in fast species. To test these predictions, we used long-term capture-recapture datasets (more than 15,000 individuals marked from 1965 to 2015) on different surveyed populations of three amphibian species in Western Europe: Triturus cristatus, Bombina variegata, and Salamandra salamandra. Despite substantial intraspecific variation, our study revealed that these three species differ in their position on a slow-fast gradient of pace of life. Our results also suggest that the differences in life history tactics influence amphibian responses to NAO fluctuations: Adult survival was most affected by the NAO in the species with the fastest pace of life (T. cristatus), whereas recruitment was most impacted in species with a slower pace of life (B. variegata and S. salamandra). In the context of climate change, our findings suggest that the capacity of organisms to deal with future changes in NAO values could be closely linked to their position on the fast-slow continuum. © 2017 John Wiley & Sons Ltd.

Proliferative events experimentally induced by a transient cold shock in the brain of adult terrestrial heterothermic vertebrates: preliminary analysis of PCNA expression in Podarcis sicula.

PubMed

Margotta, Vito

2014-01-01

In past studies on the encephalic regenerative phenomena some authors adopted a pre-surgi- cal stratagem (drastic, sudden, transient thermal stimulus) to adult brain-injured newts to limit death rate upon surgery and with this method, unexpected tissue reparation was obtained. This procedure became a routine technicality also in frog and lizard to stimulate an increase in the neurogenesis, attributable to putative stem cells which appear either in clusters ("matrix areas" or "matrix zones"), mostly at or near the telencephalic ventricular surfaces, or scattered ("matrix cells") within other cerebral districts. On the basis of this literature background, planning an immunocytochemical re-evaluation of the survival of latent proliferative properties in these adult cold shocked organisms, as already studied in Triturus carnifex, the actual investigation was carried out on the brain of Podarcis sicula not subjected to cerebral injury. The immunohistochem- ical expression of the proliferating cell nuclear antigen (PCNA) seemed moderate only in those encephalic portions better provided with cells in stand-by: the olfactory peduncles and the telen- cephalic zonae germinativae ventrales. This scenario appeared rather disappointed and inadequate with respect to the unexpected, widespread restoration of the removed portions observed by previous authors. These findings could be due both to a small effectiveness of a relatively mild thermal stress, depending on the difference between the applied temperature and seasonal one, to the lack of other experimental conditions (surgical trauma, encephalic injury) adopted in the past, and to the interspecific differences in sensitivity, since lacertilian Reptiles are less endowed with proliferative/regenerative power than Amphibians, mainly Urodela, and Teleosts.

An Extremely Peramorphic Newt (Urodela: Salamandridae: Pleurodelini) from the Latest Oligocene of Germany, and a New Phylogenetic Analysis of Extant and Extinct Salamandrids.

PubMed

Marjanović, David; Witzmann, Florian

2015-01-01

We describe an Oligocene newt specimen from western Germany that has gone practically unnoticed in the literature despite having been housed in the Museum für Naturkunde (Berlin) for a century. It is referable to the coeval Chelotriton, but is unusually peramorphic; for many characters it is more peramorphic than all other caudates or even all other lissamphibians. Most noticeable are the position of the jaw joints far caudal to the occiput, the honeycombed sculpture on the maxilla, and the possible presence of a septomaxilla (which would be unique among salamandrids). Referral to a species would require a revision of the genus, but the specimen likely does not belong to the type species. A phylogenetic analysis of nonmolecular characters of Salamandridae, far larger than all predecessors, confirms the referral to Chelotriton. It further loosely associates the Oligocene Archaeotriton and the Miocene Carpathotriton with the extant Lissotriton, though the former may alternatively lie outside Pleurodelinae altogether. The Miocene? I. randeckensis may not belong to the extant Ichthyosaura. The Miocene "Triturus" roehrsi is found neither with the extant Ommatotriton nor with Lissotriton, but inside an Asian/aquatic clade or, when geographic distribution is included as a character, as the sister-group to all other European molgins. The main cause for discrepancies between the results and the molecular consensus is not heterochrony, but adaptations to a life in mountain streams; this is the most likely reason why the Paleocene Koalliella from western Europe forms the sister-group to some or all of the most aquatic extant newts in different analyses. We would like to urge neontologists working on salamandrids to pay renewed attention to the skeleton, not limited to the skull, as a source of diagnostic and phylogenetically informative characters.

Comparing pseudo-absences generation techniques in Boosted Regression Trees models for conservation purposes: A case study on amphibians in a protected area.

PubMed

Cerasoli, Francesco; Iannella, Mattia; D'Alessandro, Paola; Biondi, Maurizio

2017-01-01

Boosted Regression Trees (BRT) is one of the modelling techniques most recently applied to biodiversity conservation and it can be implemented with presence-only data through the generation of artificial absences (pseudo-absences). In this paper, three pseudo-absences generation techniques are compared, namely the generation of pseudo-absences within target-group background (TGB), testing both the weighted (WTGB) and unweighted (UTGB) scheme, and the generation at random (RDM), evaluating their performance and applicability in distribution modelling and species conservation. The choice of the target group fell on amphibians, because of their rapid decline worldwide and the frequent lack of guidelines for conservation strategies and regional-scale planning, which instead could be provided through an appropriate implementation of SDMs. Bufo bufo, Salamandrina perspicillata and Triturus carnifex were considered as target species, in order to perform our analysis with species having different ecological and distributional characteristics. The study area is the "Gran Sasso-Monti della Laga" National Park, which hosts 15 Natura 2000 sites and represents one of the most important biodiversity hotspots in Europe. Our results show that the model calibration ameliorates when using the target-group based pseudo-absences compared to the random ones, especially when applying the WTGB. Contrarily, model discrimination did not significantly vary in a consistent way among the three approaches with respect to the tree target species. Both WTGB and RDM clearly isolate the highly contributing variables, supplying many relevant indications for species conservation actions. Moreover, the assessment of pairwise variable interactions and their three-dimensional visualization further increase the amount of useful information for protected areas' managers. Finally, we suggest the use of RDM as an admissible alternative when it is not possible to individuate a suitable set of species as a representative target-group from which the pseudo-absences can be generated.

Transient outward currents and changes of their gating properties after cell activation in thrombocytes of the newt.

PubMed Central

Kawa, K

1987-01-01

1. The electrical properties of the cell membrane of thrombocytes in the newt, Triturus pyrrhogaster, were studied using the whole-cell variation of the patch-electrode voltage-clamp technique. 2. In medium containing Ca2+ (1.8 mM), activated thrombocytes became round and then spread on the glass. Activation of thrombocytes was inhibited by the removal of external Ca2+ and addition of 1 w/v% albumin to the external media. 3. For thrombocytes kept in the resting state, depolarizations more positive than -30 mV evoked transient outward currents which decayed completely during the duration of the depolarization (150 ms). The half-decay time of the currents became smaller as the depolarizing pulse strengthened, reaching about 20 ms at +30 mV (20 degrees C). 4. The outward currents are identified as K+ currents, since (1) their reversal potential depended on extracellular K+ concentration and (2) the outward currents were suppressed either by external application of 4-aminopyridine (1 mM) or by internal application of Cs+ (120 mM). The monovalent cation selectivities of the K+ channels were evaluated from the reversal potential as Tl (1.68) greater than K(1.0) greater than Rb (0.89) greater than NH4 (0.13) greater than Na(less than 0.03). 5. When the thrombocytes had been activated, depolarization again evoked K+ currents. The currents, however, showed negligible or small decay during the duration of the depolarization (150 ms). The rate of recovery from preceding depolarization was also reduced to about one-sixth. 6. The sensitivity to 4-aminopyridine and the selectivity of the K+ channels were not changed by cell activation. 7. We conclude that during activation of thrombocytes the inactivation of the K+ channels is almost eliminated. Removal of inactivation of the K+ channels was also induced in resting thrombocytes by intracellular application of 4-bromoacetamide (50 microM). PMID:2443665

Genetic fingerprinting proves cross-correlated automatic photo-identification of individuals as highly efficient in large capture–mark–recapture studies

PubMed Central

Drechsler, Axel; Helling, Tobias; Steinfartz, Sebastian

2015-01-01

Capture–mark–recapture (CMR) approaches are the backbone of many studies in population ecology to gain insight on the life cycle, migration, habitat use, and demography of target species. The reliable and repeatable recognition of an individual throughout its lifetime is the basic requirement of a CMR study. Although invasive techniques are available to mark individuals permanently, noninvasive methods for individual recognition mainly rest on photographic identification of external body markings, which are unique at the individual level. The re-identification of an individual based on comparing shape patterns of photographs by eye is commonly used. Automated processes for photographic re-identification have been recently established, but their performance in large datasets (i.e., > 1000 individuals) has rarely been tested thoroughly. Here, we evaluated the performance of the program AMPHIDENT, an automatic algorithm to identify individuals on the basis of ventral spot patterns in the great crested newt (Triturus cristatus) versus the genotypic fingerprint of individuals based on highly polymorphic microsatellite loci using GENECAP. Between 2008 and 2010, we captured, sampled and photographed adult newts and calculated for 1648 samples/photographs recapture rates for both approaches. Recapture rates differed slightly with 8.34% for GENECAP and 9.83% for AMPHIDENT. With an estimated rate of 2% false rejections (FRR) and 0.00% false acceptances (FAR), AMPHIDENT proved to be a highly reliable algorithm for CMR studies of large datasets. We conclude that the application of automatic recognition software of individual photographs can be a rather powerful and reliable tool in noninvasive CMR studies for a large number of individuals. Because the cross-correlation of standardized shape patterns is generally applicable to any pattern that provides enough information, this algorithm is capable of becoming a single application with broad use in CMR studies for many species. PMID:25628871

The palaeoecologic and biostratigraphic evaluation of Middle Miocene freshwater sediments and microfossils near Denkendorf (Bavaria)

NASA Astrophysics Data System (ADS)

Pirkenseer, C.; Reichenbacher, B.

2009-04-01

Isolated freshwater sediments that partially cover the Jurassic limestones of the Swabian and Franconian Alb represent the northernmost expansion of the Molasse sediments. These sediments represent the analogue to the Brackish Molasse and part of the Upper Freshwater Molasse (Ottnangian to Badenian). Samples of six drillcores from the vicinity of Denkendorf (Franconian Alb, Bavaria) yielded ostracods of the superfamily Cypridoidea, frequent oogonia of charophytes, otoliths of the family Gobiidae, teeth of several taxa of micromammals as well as abundant material of amphibians, reptiles and gastropods. The sediments show a general trend from basal, more clastic influenced deposits to uniformly developed marly sediments with freshwater carbonate intercalations. The acme of microfossil occurrences is associated with the latter section. The palaeoecologic analysis characterises the environment as structured littoral zone (e.g. Pseudocandona steinheimensis, Gyraulus sp., Planorbarius sp., Rana ridibunda, Triturus sp.) of a larger oligo- to mesotrophic (Chara spp., Nitellopsis spp.) low-energy freshwater system under a warm subtropical to tropical climate (Diplocynodon cf. D. styriacus, Channa sp.). The cooccurrence of suboxia- and oligotrophy-tolerant species like Palaeocarassius sp. and Channa sp. may indicate short intervals of regional depletion of oxygene and raise of nutrient content. Mediocypris candonaeformis and Gobius latiformis represent relict species of the preceding Brackwassermolasse. Terrestrial elements include Proboscidea (phalanx), Cervidae (astragalus), land turtles (Testudo sp.) and gastropods (Clausiliidae, Pupillidae, Cepaea sp.). The occurrence of Jurassic xenoclasts and bean iron ore indicate the presence of a tributary system. The faunal and floral assemblages show close affinities to other localities of the Molasse Basin (e.g., Sandelzhausen). In accordance with the depositional history this indicates a palaeogeographic connection with the foreland basin. Furthermore the ostracod assemblage is related to taxa recorded from the Miocene infill of the (isolated) Steinheim meteorite crater (e.g., Pseudocandona steinheimensis). According to the evaluation of the micromammal molars (Megacricetodon cf. M. minor and M. cf. M. bavaricus) the sediments of Denkendorf are attributed to the lower MN5 mammal zone (latest Karpatian to early Badenian) and are thus considered to be younger than the associations found near Hitzhofen and Heitensheim.

THE RESPONSE OF X-IRRADIATED LIMBS OF ADULT URODELES TO NORMAL TISSUE GRAFTS. I. EFFECTS OF AUTOGRAFTS OF SIXTY-DAY FOREARM REGENERATES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stinson, B.D.

1963-06-01

Results are reported of autoplastic transplantation of parts of nonirradiated, regenerated forelimb to the contralateral x-irradiated forelimb in adult Triturus viridescens. The right forelimbs were exposed to various doses of localized irradiation (1000 to 5000 r) followed by amputation of both left and right forelimbs through the mid forearm. Left limbs regenerated normally, but irradiated right limbs failed to exhibit any significant degree of regenerative activity over a 3-month period. Both forelimbs were reamputated through the distal humerus and observed for an additional two months. Left limbs produced normal regenerates, but irradiated right limbs gave no gross evidence of regenerationmore » at any of the radiation dose levels. Normal left regenerates were reamputated immediately distal to the elbow on the 60th day after the second amputation; the severed forearm was trimmed with scissors along anterior and posterior borders and denuded of skin over its proximal half, leaving an essentially complete forearm region as a normal autograft. This was implanted into the irradiated right upper arm stump, after ablation of the distal half of its humerus, with normal proximodistal polarity in all cases. The irradiated stump was reamputated through the distal portion of the implanted normal autograft two weeks after implantation, and was observed for four months. Periodic gross observations showed that over 90% of irradiated upper arms formed regenerates at a rate which paralleled that of nonirradiated controls. However, regenerates formed on irradiated upper arms exhibited a restriction of morphogenetic capacity, only 60% attaining 3- and 4-digit stages. Most of the morphologically more complex regenerates which developed on the irradiated upper arm stumps manifested left limb asymmetry despite their formation on right irradiated stumps, suggesting a relation between the asymmetry of the normal graft and that of the resulting regenerate. All regenerates which developed on irradiated upper arms showed marked deficiencies in the restoration of a complete proximodistal structural pattern appropriate to the level of amputation through the irradiated stump. However, the actual pattern produced was appropriate to the level of amputation through the implanted normal autograft. These findings support the hypothesis that normal grafts promote the formation of regenerates on irradiated limbs through the autonomous developmental activity of the transected graft. (BBB)« less

Climate and environment of the earliest West European hominins inferred from amphibian and squamate reptile assemblages: Sima del Elefante Lower Red Unit, Atapuerca, Spain

NASA Astrophysics Data System (ADS)

Blain, Hugues-Alexandre; Bailon, Salvador; Cuenca-Bescós, Gloria; Bennàsar, Maria; Rofes, Juan; López-García, Juan Manuel; Huguet, Rosa; Arsuaga, Juan Luis; Bermúdez de Castro, José Maria; Carbonell, Eudald

2010-11-01

The Sima del Elefante cave, in the Sierra de Atapuerca (Burgos, Spain), is famous for the fact that level TE9 of its Lower Red Unit recently delivered the oldest hominin remains of Western Europe, identified as Homo antecessor and dated by biostratigraphy and radiometric methods to ca 1.2 Ma. Given the importance of this discovery, every effort is being made to reconstruct the landscapes where these hominins once thrived. The amphibian and squamate reptile assemblage of the Sima del Elefante Lower Red Unit is here studied for the first time. The faunal list comprises at least 17 species (roughly 12,000 bone fossil remains): Salamandra salamandra, Triturus cf. marmoratus, Alytes obstetricans, Pelobates cultripes, Pelodytes punctatus, Bufo bufo, Bufo calamita, Hyla arborea, Rana sp., cf. Pelophylax sp., Lacerta s.l., small-sized indeterminate lacertids, Anguis fragilis, Natrix cf. natrix, Natrix cf. maura, Coronella cf. girondica and Vipera sp. As the amphibians and squamate reptiles do not differ at species level from the extant herpetofauna of the Iberian Peninsula, they can contribute to the reconstruction of the landscape and climate. In this paper, the mutual climatic range and habitat weighting methods are applied to the amphibian and squamate reptile assemblages in order to estimate quantitative data. The results from the squamate and amphibian study indicate that during the hominin presence the mean annual temperature (MAT = 10-13 °C) was always slightly warmer than at present and the mean annual precipitation (MAP = 800-1000 mm) was greater than today in the Burgos area. The landscape had open habitats in the vicinity of the Atapuerca caves throughout the sequence, with wet points in the surrounding area, and a predominance of humid meadows and open woodlands. These results mainly agree with those for large mammals, small mammals and the pollen analysis. The climate and landscape of TE-LRU are very similar to those reconstructed for the TD6 "Aurora Stratum" level of the Gran Dolina cave (Atapuerca) that has yielded H. antecessor remains at ca 960 ky. When compared with Orce localities of similar age (i.e. Barranco León D and Fuente Nueva 3) that have yielded strong evidence of hominin presence (mainly lithic industries), it appears that they have a fairly similar environmental pattern, having in common a good representation of woodland and water-edge areas, even though dry environments are more developed in Barranco León D and Fuente Nueva 3 than in Sima del Elefante and Gran Dolina. H. antecessor may have thus lived under a warm-humid climate in a patchy landscape mainly composed of humid meadows and riparian woodlands. Such a landscape may have provided favourable conditions for a high diversity of large mammals, as well as for hiding and escaping from large carnivores.