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Madelaine Böhme - One of the best experts on this subject based on the ideXlab platform.
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Neogene amphibians and reptiles (Caudata, Anura, Gekkota, Lacertilia, and Testudines) from the south of Western Siberia, Russia, and Northeastern Kazakhstan.
PeerJ, 2017Co-Authors: Davit Vasilyan, Vladimir Zazhigin, Madelaine BöhmeAbstract:BACKGROUND The present-day amphibian and reptile fauna of Western Siberia are the least diverse of the Palaearctic Realm, as a consequence of the unfavourable climatic conditions that predominate in this region. The origin and emergence of these herpetofaunal groups are poorly understood. Aside from the better-explored European Neogene localities yielding amphibian and reptile fossil remains, the Neogene herpetofauna of Western Asia is understudied. The few available data need critical reviews and new interpretations, taking into account the more recent records of the European herpetofauna. The comparison of this previous data with that of European fossil records would provide data on palaeobiogeographic affiliations of the region as well as on the origin and emergence of the present-day fauna of Western Siberia. An overview of the earliest occurrences of certain amphibian lineages is still needed. In addition, studies that address such knowledge gaps can be useful for molecular biologists in their calibration of molecular clocks. METHODS AND RESULTS In this study, we considered critically reviewed available data from amphibian and reptile fauna from over 40 Western Siberian, Russian and Northeastern Kazakhstan localities, ranging from the Middle Miocene to Early Pleistocene. Herein, we provided new interpretations that arose from our assessment of the previously published and new data. More than 50 amphibians and reptile taxa were identified belonging to families Hynobiidae, Cryptobranchidae, Salamandridae, Palaeobatrachidae, Bombinatoridae, Pelobatidae, Hylidae, Bufonidae, Ranidae, Gekkonidae, Lacertidae, and Emydidae. Palaeobiogeographic analyses were performed for these groups and palaeoprecipitation values were estimated for 12 localities, using the bioclimatic analysis of herpetofaunal assemblages. CONCLUSION The Neogene assemblage of Western Siberia was found to be dominated by groups of European affinities, such as Palaeobatrachidae, Bombina, Hyla, Bufo bufo, and a small part of this assemblage included Eastern Palaearctic taxa (e.g. Salamandrella, Tylototriton, Bufotes viridis). For several taxa (e.g. Mioproteus, Hyla, Bombina, Rana temporaria), the Western Siberian occurrences represented their most eastern Eurasian records. The most diverse collection of fossil remains was found in the Middle Miocene. Less diversity has been registered towards the Early Pleistocene, potentially due to the progressive cooling of the climate in the Northern Hemisphere. The results of our study showed higher-amplitude changes of precipitation development in Western Siberia from the Early Miocene to the Pliocene, than previously assumed.
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Ontogenetic diversity within Cryptobranchidae.
2013Co-Authors: Davit Vasilyan, Madelaine BöhmeAbstract:Ontogenetic diversity within Cryptobranchidae.
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pronounced peramorphosis in lissamphibians aviturus exsecratus urodela Cryptobranchidae from the paleocene eocene thermal maximum of mongolia
PLOS ONE, 2012Co-Authors: Davit Vasilyan, Madelaine BöhmeAbstract:Background The oldest and largest member of giant salamanders (Cryptobranchidae) Aviturus exsecratus appears in the latest Paleocene (near the Paleocene–Eocene Thermal Maximum) of Mongolia. Based on femoral and vertebral morphology and metrics, a terrestrial adaptation has been supposed for this species. Methodology/Principal Findings A detailed morphological reinvestigation of published as well as unpublished material reveals that this salamander shows a vomerine dentition that is posteriorly shifted and arranged in a zigzag pattern, a strongly developed olfactory region within the cranial cavity, and the highest bone ossification and relatively longest femur among all fossil and recent cryptobranchids. Conclusions/Significance The presence of these characteristics indicates a peramorphic developmental pattern for Aviturus exsecratus. Our results from Av. exsecratus indicate for the first time pronounced peramorphosis within a crown-group lissamphibian. Av. exsecratus represents a new developmental trajectory within both fossil and recent lissamphibian clades characterized by extended ontogeny and large body size, resembling the pattern known from late Paleozoic eryopines. Moreover, Av. exsecratus is not only a cryptobranchid with distinctive peramorphic characters, but also the first giant salamander with partially terrestrial (amphibious) lifestyle. The morphology of the vomers and dentaries suggests the ability of both underwater and terrestrial feeding.
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habitat tracking range dynamics and palaeoclimatic significance of eurasian giant salamanders Cryptobranchidae indications for elevated central asian humidity during cenozoic global warm periods
Palaeogeography Palaeoclimatology Palaeoecology, 2012Co-Authors: Madelaine Böhme, Davit Vasilyan, Michael WinklhoferAbstract:article i nfo Environmental fluctuations are a driving force in vertebrate evolution, but cryptobranchids (giant salamanders) show little morphologic change since the Jurassic. Here we analyze their fossil distribution in the Cenozoic of Eurasia and show that morphologic stasis is also maintained by stable environments, making giant salamanders an ideal proxy-group for environmental and palaeoclimatic studies. The climate space of recent and fossil cryptobranchids is best characterized by high humidity with mean annual precipitation values over 900 mm. The recorded patchiness of their fossil record can be explained by habitat tracking and/or range expansion from higher altitudes into lowland settings during humid periods with increased basinal relief. In Central Asia cryptobranchids are recorded from five intervals, four of them are global warm periods: Paleocene-Eocene Thermal Maximum, Late Oligocene warming, Miocene Climate Optimum, and Mio-Pliocene transition. This distribution suggests that during global warmth the Asian cold high pressure zone during winter months may be weak or absent, thus moist westerly winds penetrate far into the continent. The presence of cryptobranchids also indicates that the aridification across the Eocene- Oligocene boundary as reported from Mongolia and northwestern China, does not occur in the Zaysan Basin, probably due to increased upslope precipitation in the rising Altai Mountains.
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The palaeoclimatic significance of Eurasian Giant Salamanders (Cryptobranchidae: Zaissanurus, Andrias) - indications for elevated humidity in Central Asia during global warm periods (Eocene, late Oligocene warming, Miocene Climate Optimum)
2010Co-Authors: Davit Vasilyan, Madelaine Böhme, Michael WinklhoferAbstract:Cryptobranchids represent a group of large sized (up to 1.8 m) tailed amphibians known since the Middle Jurassic (Gao & Shubin 2003). Two species are living today in eastern Eurasia: Andrias davidianus (China) and A. japonicus (Japan). Cenozoic Eurasian fossil giant salamanders are known with two genera and two or three species from over 30 localities, ranging from the Late Eocene to the Early Pliocene (Bohme & Ilg 2003). The Late Eocene species Zaissanurus beliajevae is restricted to the Central Asian Zaissan Basin (SE-Kazakhstan, 50°N, 85°E), whereas the Late Oligocene to Early Pliocene species Andrias scheuchzeri is distributed from Central Europe to the Zaissan Basin. In the latter basin the species occur during two periods; the latest Oligocene and the late Early to early Middle Miocene (Chkhikvadse 1982). Andrias scheuchzeri is osteological indistinguishable from both recent species, indicating a similar ecology (Westfahl 1958). To investigate the palaeoclimatic significance of giant salamanders we analyzed the climate within the present-day distribution area and at selected fossil localities with independent palaeoclimate record. Our results indicate that fossil and recent Andrias species occur in humid areas where the mean annual precipitation reach over 900 mm (900 – 1.300 mm). As a working hypothesis (assuming a similar ecology of Andrias and Zaissanurus) we interpret occurrences of both fossil Eurasian giant salamanders as indicative for humid palaeoclimatic conditions. Based on this assumption the Late Eocene, the latest Oligocene (late Oligocene warming) and the late Early to early Middle Miocene (Miocene Climatic Optimum) of Central Asia (Zaissan Basin) are periods of elevated humidity, suggesting a direct (positive) relationship between global climate and Central Asian humidity evolution.
Davit Vasilyan - One of the best experts on this subject based on the ideXlab platform.
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revision of chunerpeton tianyiense lissamphibia caudata is it a cryptobranchid salamander
Palaeoworld, 2020Co-Authors: Yufen Rong, Davit Vasilyan, Liping Dong, Yuan WangAbstract:Abstract Lacustrine deposits of Juro-Cretaceous age in northeastern China have yielded some of the best-preserved fossils of early crown salamanders. One of those taxa, Chunerpeton tianyiense, has been considered as a crown or stem member of the family Cryptobranchidae, significant for implying a long evolutionary history for cryptobranchids and for calibrating the molecular clock of Caudata evolution. Building on the most recent large-scale phylogenetic analysis of relationships among fossil and recent salamanders and utilizing new specimens of Chunerpeton, we update the osteological description and diagnosis for Chunerpeton and reconsider its phylogenetic relationships. On the basis of recently collected Chunerpeton skeletons from the type locality at Daohugou, Inner Mongolia, China and available literature, we update the taxon-character matrix and run phylogenetic analyses with constraints on the relationships among families using a molecular backbone. We redescribe the osteology of Chunerpeton, revise and identify some new characters including large anterodorsal fenestra bordered by paired premaxillae, nasals, and frontals; nasals separate and wider than frontal; contact between nasal and prefrontal present; lacrimal present; and contact between pterygoid and parasphenoid absent. Osteological comparisons between Chunerpeton and living cryptobranchids reveal a suite of distinct differences in snout shape and in configurations, positions, and contacts of certain skull bones. Our phylogenetic analyses consistently place Chunerpeton as a stem Caudata outside of Cryptobranchidae and crown salamanders. Exclusion of Chunerpeton from Cryptobranchidae will require reconsideration of the origin time for Cryptobranchidae and recalibration of the molecular clock for the whole caudatan tree.
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Neogene amphibians and reptiles (Caudata, Anura, Gekkota, Lacertilia, and Testudines) from the south of Western Siberia, Russia, and Northeastern Kazakhstan.
PeerJ, 2017Co-Authors: Davit Vasilyan, Vladimir Zazhigin, Madelaine BöhmeAbstract:BACKGROUND The present-day amphibian and reptile fauna of Western Siberia are the least diverse of the Palaearctic Realm, as a consequence of the unfavourable climatic conditions that predominate in this region. The origin and emergence of these herpetofaunal groups are poorly understood. Aside from the better-explored European Neogene localities yielding amphibian and reptile fossil remains, the Neogene herpetofauna of Western Asia is understudied. The few available data need critical reviews and new interpretations, taking into account the more recent records of the European herpetofauna. The comparison of this previous data with that of European fossil records would provide data on palaeobiogeographic affiliations of the region as well as on the origin and emergence of the present-day fauna of Western Siberia. An overview of the earliest occurrences of certain amphibian lineages is still needed. In addition, studies that address such knowledge gaps can be useful for molecular biologists in their calibration of molecular clocks. METHODS AND RESULTS In this study, we considered critically reviewed available data from amphibian and reptile fauna from over 40 Western Siberian, Russian and Northeastern Kazakhstan localities, ranging from the Middle Miocene to Early Pleistocene. Herein, we provided new interpretations that arose from our assessment of the previously published and new data. More than 50 amphibians and reptile taxa were identified belonging to families Hynobiidae, Cryptobranchidae, Salamandridae, Palaeobatrachidae, Bombinatoridae, Pelobatidae, Hylidae, Bufonidae, Ranidae, Gekkonidae, Lacertidae, and Emydidae. Palaeobiogeographic analyses were performed for these groups and palaeoprecipitation values were estimated for 12 localities, using the bioclimatic analysis of herpetofaunal assemblages. CONCLUSION The Neogene assemblage of Western Siberia was found to be dominated by groups of European affinities, such as Palaeobatrachidae, Bombina, Hyla, Bufo bufo, and a small part of this assemblage included Eastern Palaearctic taxa (e.g. Salamandrella, Tylototriton, Bufotes viridis). For several taxa (e.g. Mioproteus, Hyla, Bombina, Rana temporaria), the Western Siberian occurrences represented their most eastern Eurasian records. The most diverse collection of fossil remains was found in the Middle Miocene. Less diversity has been registered towards the Early Pleistocene, potentially due to the progressive cooling of the climate in the Northern Hemisphere. The results of our study showed higher-amplitude changes of precipitation development in Western Siberia from the Early Miocene to the Pliocene, than previously assumed.
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Ontogenetic diversity within Cryptobranchidae.
2013Co-Authors: Davit Vasilyan, Madelaine BöhmeAbstract:Ontogenetic diversity within Cryptobranchidae.
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pronounced peramorphosis in lissamphibians aviturus exsecratus urodela Cryptobranchidae from the paleocene eocene thermal maximum of mongolia
PLOS ONE, 2012Co-Authors: Davit Vasilyan, Madelaine BöhmeAbstract:Background The oldest and largest member of giant salamanders (Cryptobranchidae) Aviturus exsecratus appears in the latest Paleocene (near the Paleocene–Eocene Thermal Maximum) of Mongolia. Based on femoral and vertebral morphology and metrics, a terrestrial adaptation has been supposed for this species. Methodology/Principal Findings A detailed morphological reinvestigation of published as well as unpublished material reveals that this salamander shows a vomerine dentition that is posteriorly shifted and arranged in a zigzag pattern, a strongly developed olfactory region within the cranial cavity, and the highest bone ossification and relatively longest femur among all fossil and recent cryptobranchids. Conclusions/Significance The presence of these characteristics indicates a peramorphic developmental pattern for Aviturus exsecratus. Our results from Av. exsecratus indicate for the first time pronounced peramorphosis within a crown-group lissamphibian. Av. exsecratus represents a new developmental trajectory within both fossil and recent lissamphibian clades characterized by extended ontogeny and large body size, resembling the pattern known from late Paleozoic eryopines. Moreover, Av. exsecratus is not only a cryptobranchid with distinctive peramorphic characters, but also the first giant salamander with partially terrestrial (amphibious) lifestyle. The morphology of the vomers and dentaries suggests the ability of both underwater and terrestrial feeding.
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habitat tracking range dynamics and palaeoclimatic significance of eurasian giant salamanders Cryptobranchidae indications for elevated central asian humidity during cenozoic global warm periods
Palaeogeography Palaeoclimatology Palaeoecology, 2012Co-Authors: Madelaine Böhme, Davit Vasilyan, Michael WinklhoferAbstract:article i nfo Environmental fluctuations are a driving force in vertebrate evolution, but cryptobranchids (giant salamanders) show little morphologic change since the Jurassic. Here we analyze their fossil distribution in the Cenozoic of Eurasia and show that morphologic stasis is also maintained by stable environments, making giant salamanders an ideal proxy-group for environmental and palaeoclimatic studies. The climate space of recent and fossil cryptobranchids is best characterized by high humidity with mean annual precipitation values over 900 mm. The recorded patchiness of their fossil record can be explained by habitat tracking and/or range expansion from higher altitudes into lowland settings during humid periods with increased basinal relief. In Central Asia cryptobranchids are recorded from five intervals, four of them are global warm periods: Paleocene-Eocene Thermal Maximum, Late Oligocene warming, Miocene Climate Optimum, and Mio-Pliocene transition. This distribution suggests that during global warmth the Asian cold high pressure zone during winter months may be weak or absent, thus moist westerly winds penetrate far into the continent. The presence of cryptobranchids also indicates that the aridification across the Eocene- Oligocene boundary as reported from Mongolia and northwestern China, does not occur in the Zaysan Basin, probably due to increased upslope precipitation in the rising Altai Mountains.
HIDEO HASEGAWA - One of the best experts on this subject based on the ideXlab platform.
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morphology ultrastructure and molecular characterisation of spiroxys japonica morishita 1926 spirurida gnathostomatidae from pelophylax nigromaculatus hallowell amphibia ranidae
Parasitology Research, 2014Co-Authors: Liang Li, Vicente Roca, Akiko Sato, HIDEO HASEGAWA, Zhen Xu, Luping ZhangAbstract:Gnathostomatid nematodes identified morphologically as Spiroxys japonica Morishita, 1926 were collected from the dark-spotted frog Pelophylax nigromaculatus (Hallowell) (Amphibia: Ranidae) in China. Light and scanning electron microscopy were used to study the morphology of this species in detail. Previously unreported morphological features are revealed and others corrected. In addition, adult nematodes of S. japonica collected from P. nigromaculatus and Spiroxys hanzaki Hasegawa, Miyata & Doi, 1998 collected from Andrias japonicus (Temminck) (Caudata: Cryptobranchidae) in China and Japan, respectively, and the third-stage larva of S. japonica collected from Lithobates catesbeianus (Shaw) (Anura: Ranidae) in Japan, were characterised using molecular methods by sequencing and analysing ribosomal [large ribosomal DNA (18S) and internal transcribed space] and mitochondrial [cytochrome c oxidase subunit 1] target regions, respectively. The new morphological and genetic data contributes to a more accurate diagnosis of this hitherto little known nematode genus.
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liolope copulans trematoda digenea liolopidae parasitic in andrias japonicus amphibia caudata Cryptobranchidae in japan life cycle and systematic position inferred from morphological and molecular evidence
Parasitology International, 2011Co-Authors: Takashi Baba, Takeyoshi Tochimoto, Masatomi Hosoi, Misako Urabe, Takeshi Shimazu, HIDEO HASEGAWAAbstract:The life cycle of Liolope copulans Cohn, 1902 (Trematoda: Digenea: Liolopidae), an intestinal parasite of the Japanese giant salamander Andrias japonicus (Temminck) (Amphibia: Caudata: Cryptobranchidae), was studied in the field and laboratory in Japan. This is the first description of mother sporocyst, daughter sporocyst and cercariae of a liolopid species. Non-oculate longifurcate pharyngeate cercariae were formed in lanceolate-cylindrical daughter sporocysts in Semisulcospira libertina (Gould) (Gastropoda: Sorbeoconcha: Pleuroceridae). They successfully developed to encapsulated metacercariae in cyprinid fishes, Nipponocypris sieboldii (Temminck and Schlegel) and Rhynchocypris lagowskii (Dybowski), by experimental infection. Cercariae had a V-shaped excretory vesicle with two looped arms, as in metacercariae and adults. Developmental stages from mother sporocyst to adult are described and illustrated. DNA sequencing was conducted for 28S and 18S rDNA of mother and daughter sporocysts, cercariae, and an adult. The result of molecular phylogenetic analysis suggests that L. copulans may be one of the basal taxa of the order Diplostomida Olson, Cribb, Tkach, Bray, and Littlewood, 2003, but its systematic position is still unclear because of the topological inconsistence between the 28S and 18S trees. Therefore, we tentatively place the family Liolopidae in the superfamily Diplostomoidea, mainly based on the morphology of sporocysts and cercariae.
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Helminths from the Hellbender, Cryptobranchus alleganiensis (Urodela: Cryptobranchidae), in Missouri, U.S.A.
Comparative Parasitology, 2003Co-Authors: HIDEO HASEGAWA, Yatsukaho IkedaAbstract:Two hellbenders, Cryptobranchus alleganiensis (Urodela: Cryptobranchidae), from Missouri, U.S.A., were examined for helminths. Three nematode species, Falcaustra catesbeianae Walton, 1929, Urodelnema mackini (Walton, 1941), and Kamegainema cingula (Linstow, 1902) and 1 proteocephalid cestode species were found. This is the first record of Fa. catesbeianae from the hellbender. Kamegainema cingula, normally a dermal nematode of cryptobranchids, is reported for the first time infecting the body cavity.
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Parasitic Helminths Collected from the Japanese Giant Salamander, Andrias japonicus (Temminck, 1837) (Amphibia: Cryptobranchidae), in Japan
Comparative Parasitology, 2002Co-Authors: HIDEO HASEGAWA, Toshio Doi, Takeyoshi Tochimoto, Akira MyataAbstract:Helminth parasites collected at postmortem from the alimentary tracts of 5 Japanese giant salamanders, Andrias japonicus (Temminck, 1837), are reported. One trematode, Liolope copulans (Cohn, 1902); and 5 nematodes, Amphibiocapillaria tritonispunctati (Diesing, 1851), Dioctophyme renale (Goeze, 1782) (larva), Spiroxys hanzaki Hasegawa, Miyata et Doi, 1998, Kathlaniidae sp. (larva), and Physalopteroidea sp. (larva) were found. Examination of premolt and molting larvae of S. hanzaki showed that the advanced third-stage larvae molt directly to the adult stage. Strict host specificity of some helminths is surmised to be linked to the piscivorous nature of the giant salamander. This is the first report of A. tritonispunctati and D. renale from A. japonicus. The chromosome number of L. copulans is recorded for the first time.
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Spiroxys hanzaki n. sp. (Nematoda: Gnathostomatidae) collected from the giant salamander, Andrias japonicus (Caudata: Cryptobranchidae), in Japan
The Journal of parasitology, 1998Co-Authors: HIDEO HASEGAWA, Akira Miyata, Toshio DoiAbstract:Spiroxys hanzaki n. sp. (Nematoda: Gnathostomatidae) taken from the giant salamander, Andrias japonicus (Temminck, 1836) (Caudata: Cryptobranchidae) from Hyogo Prefecture, Japan, is described. It closely resembles Spiroxys allegheniensis Walton, 1930, from the hellbender, Cryptobranchus alleganiensis (Daudin, 1803) (Cryptobranchidae), of North America, in that it has minute dorsal and ventral lobes of the pseudolabium and a reduced gubernaculum but is readily distinguished by a pseudolabium with 2 apical, 1 dorsal, and 1 ventral tooth on the median lobe.
Song Huang - One of the best experts on this subject based on the ideXlab platform.
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Four complete mitochondrial genomes of living wild-type chinese giant salamander Andrias davidianus (Amphibia: Cryptobranchidae)
Mitochondrial DNA Part B, 2018Co-Authors: Li-fang Peng, Yan-rong Chen, Dian-cheng Yang, Shi-yang Weng, Yong Zhang, Song HuangAbstract:The Chinese giant salamander (CGS), Andrias davidianus (Amphibian, Caudata, Cryptobranchidae), is endemic to China. After overhunting in the 1990’s, it is very difficult to find the CGS in the wild...
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complete mitochondrial genome of a living wild type chinese giant salamander andrias davidianus amphibia Cryptobranchidae in huangshan
Mitochondrial DNA Part B, 2016Co-Authors: Dian-cheng Yang, Yan-rong Chen, Song HuangAbstract:The Chinese giant salamander, Andrias davidianus, is the biggest extant amphibian in the world. The population from Huangshan is distinct from other populations. The complete mitochondrial genome of a living wild-type Chinese giant salamander from Huangshan was sequenced. The total length is 16,565 bp, containing 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes and a D-loop. The phylogenetic tree of A. davidianus and 12 other closely species belonging to the order Caudata was reconstructed.
Tomoko Tanaka-ueno - One of the best experts on this subject based on the ideXlab platform.
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Reduced genetic variation in the Japanese giant salamander, Andrias japonicus (Amphibia: Caudata)
Molecular phylogenetics and evolution, 2008Co-Authors: Masafumi Matsui, Atsushi Tominaga, Wan-zhao Liu, Tomoko Tanaka-uenoAbstract:The phylogenetic relationships among 46 samples from 27 populations of the Japanese giant salamander, Andrias japonicus and its congener, A. davidianus from China was investigated, using 3664 bp sequences of the mitochondrial genes NADH1, NADH3, cyt b and CR, partial NADH6 and intervening genes. In phylogenetic trees constructed by MP, ML, and Bayesian methods, the family Cryptobranchidae and the genus Andrias both form monophyletic groups. Japanese A. japonicus and Chinese A. davidianus are sister taxa and can be regarded as separate species despite a small degree of genetic differentiation. Andrias japonicus is divided into central and western clades, but the phylogenetic relationships within the latter clade are unresolved. As previously reported from allozyme analyses, A. japonicus exhibits little genetic differentiation, in strong contrast to salamanders of the genus Hynobius with which their distributions overlap. This reduced genetic variability in A. japonicus is attributable to a unique mating system of polygyny, delayed sexual maturity, notable longevity, life in a stable aquatic environment, and gigantism, as well as bottleneck effects following habitat fragmentation and extinction of local populations during Quaternary glaciations. The species is thus susceptible to extinction by potential environmental fluctuations, and requires extensive conservation measures.