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Masafumi Matsui - One of the best experts on this subject based on the ideXlab platform.
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a revision of hynobius stejnegeri a lotic breeding salamander from western japan with a description of three new species amphibia caudata Hynobiidae
Zootaxa, 2019Co-Authors: Atsushi Tominaga, Masafumi Matsui, Shingo Tanabe, Kanto NishikawaAbstract:A lotic-breeding salamander Hynobius stejnegeri, formerly called H. yatsui, from western Japan is revised based on genetic and morphological evidence, and three species are described: H. guttatus sp. nov. from Chubu-Kinki districts of Honshu Island, H. tsurugiensis sp. nov. from east highland of Shikoku Island, and H. kuishiensis sp. nov. from other parts of Shikoku Island. Thus, H. stejnegeri sensu stricto is restricted to Kyushu Island. Of these four species, H. kuishiensis sp. nov. contains two distinct mitochondrial lineages, but this split is not reflected in differentiation of allozyme (nuclear genome) markers. These species are morphologically similar to each other but can be differentiated by several characteristics, especially in combination of dorsal coloration, the number of vomerine, upper, and lower jaw teeth, and depth of vomerine teeth series. In coloration, H. guttatus sp. nov. is brown or dark brown mostly with tiny white to brownish white marking, while H. tsurugiensis sp. nov. is dark brown with bright yellow continuous markings. Hynobius kuishiensis sp. nov. is reddish purple or dark brown with small to continuous brownish white markings, in contrast to reddish purple or dark brown with small to large brownish white markings in H. stejnegeri.
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systematics of the widely distributed japanese clouded salamander hynobius nebulosus amphibia caudata Hynobiidae and its closest relatives
Current Herpetology, 2019Co-Authors: Masafumi Matsui, Kanto Nishikawa, Natsuhiko Yoshikawa, Gen Aoki, Shingo Tanabe, Yasuchika Misawa, Hiroshi Okawa, Koshiro Eto, Atsushi TominagaAbstract:The abundant clouded salamander from western Japan, Hynobius nebulosus, has long been considered a single widespread species, although some authors have suggested the inclusion of several cryptic species. This led to a molecular and morphological analysis of populations from all parts of the known range. Phylogenetic relationships were inferred from complete sequences of the mitochondrial cytochrome b gene, and nuclear genome differentiations were estimated by multiplexed inter simple sequence repeat genotyping by sequencing (MIG-seq). The results suggest that H. nebulosus hitherto recognized consists of at least nine species. We applied existing names to two of them, H. nebulosus (Temminck et Schlegel) and H. vandenburghi Dunn, and described seven others as new species.
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two new species of lotic breeding salamanders amphibia caudata Hynobiidae from western japan
Zootaxa, 2019Co-Authors: Atsushi Tominaga, Masafumi Matsui, Kanto NishikawaAbstract:Two new species of lotic-breeding salamanders, Hynobius sematonotos and H. oyamai, are described from Chugoku district and northeastern Kyushu district, respectively, western Japan. They are members of the so-called H. naevius group and are phylogenetically close to H. naevius, H. katoi, and H. hirosei but divergent from them with large genetic distances. These new species have been treated as Chugoku and northeastern Kyushu lineages, respectively, of H. naevius to which they are morphologically very similar. However, these new species can be differentiated from H. naevius by several morphological traits. Hynobius sematonotos is characterized and discriminated from other species by combination of small body size, a shallow vomerine teeth series with small number of vomerine teeth, small number of upper and lower jaw teeth, relatively long head and snout, and large upper eyelid, relatively short axilla-groin, reddish purple ground color with grayish brown marking on the dorsum, and reddish to bluish gray ventral ground color with relatively large markings varying from pale-white to white. Hynobius oyamai is characterized and discriminated from other species by large body size, moderately deep vomerine teeth series with a medium number of vomerine teeth, large number of upper and lower jaw teeth, relatively wide internarial and long fifth toe, bluish purple ground color sometimes with pale white marking on dorsum. Hynobius sematonotos occurs in Honshu, disjunct from H. naevius and H. oyamai that occur allopatrically in Kyushu.
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historical demography of an endangered salamander ranodon sibiricus amphibia urodela Hynobiidae a reassessment
Zoological Science, 2017Co-Authors: Kanto Nishikawa, Tatjana Dujsebayeva, Natsuhiko Yoshikawa, Masafumi Matsui, Atsushi TominagaAbstract:Chinese populations of the endangered Siberian salamander Ranodon sibiricus are reported to have diverged only about 120 years ago, and to have the lowest genetic diversity of any amphibian. However, these conclusions require verification, as the main range of the species is in Kazakhstan. Moreover, the generation time used for estimating divergence time has a weak ground. In order to clarify these problems, we investigated the molecular phylogenetic relationship and historical demography of the species covering its whole distribution range using the mitochondrial DNA region reported for Chinese population (1072 bp sequences of the control region), while conducting skeletochronological analysis to estimate accurate generation time. As a result, the range expansion was estimated at 88,000–50,000 YA, based on the generation time of 6–10 years. Degree of intraspecific genetic differentiation is actually very small, but, as a single species, is not so small as had been reported for Chinese population alone.
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two new salamanders of the genus onychodactylus from eastern honshu japan amphibia caudata Hynobiidae
Zootaxa, 2014Co-Authors: Natsuhiko Yoshikawa, Masafumi MatsuiAbstract:We describe two new species of hynobiid salamanders in the genus Onychodactylus from eastern Honshu, Japan, based on the morphological and genetic evidence. Onychodactylus intermedius sp. nov. is distributed in southern part of Tohoku District and northern Ibaraki and Niigata Prefectures, and was previously reported as S-Tohoku group. Onychodactylus intermedius belongs to the O. japonicus species complex, and differs from the other congeners in having relatively long tail, narrow head, short snout, 18 presacral vertebrae, and distinctly curved vomerine tooth series without gap. Onychodactylus fuscus sp. nov. is known from only four localities in Fukushima and Niigata Prefectures of Tohoku and Hokuriku Districts. It also belongs to the O. japonicus complex, but lacks the dorsal stripe, which is a diagnostic character of the species complex. In other characteristics, O. fuscus differs from the other congeners in having comparatively long tail, wide head and internarial space, shallowly curved vomerine tooth series with gap, and relatively few vomerine teeth. Both species described here breed in winter. Phylogenetically, the two new species are closely related to each other, forming a well-supported clade with O. tsukubaensis as their sister species. Onychodactylus intermedius sp. nov. is known to be parapatric with O. japonicus and O. nipponoborealis without hybridization, whereas O. fuscus sp. nov. is sympatric with O. japonicus at least in a single known locality, and analysis of microsatellite loci indicates they are reproductively isolated.
Kanto Nishikawa - One of the best experts on this subject based on the ideXlab platform.
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osteological characteristics of the setouchi salamander hynobius setouchi urodela Hynobiidae
Anatomical Record-advances in Integrative Anatomy and Evolutionary Biology, 2021Co-Authors: Sotaro Hara, Kanto NishikawaAbstract:This study described the detailed osteological features of the Setouchi salamander Hynobius setouchi. H. setouchi, which is endemic to central Japan, was recently delineated from the wide range of H. nebulosus species based on molecular and external morphological characteristics. However, the osteological features of the species belonging to the genus Hynobius have not been examined, which has hindered the detailed understanding of morphological diversity in the genus. To address this problem, this study elucidated the osteological features of the salamander using micro-computed tomography scanning and whole-mount double staining methods. The articular, a part of the hypobranchial I, a part of coracoid, pubis, carpus, and tarsus were cartilaginous in small-sized individuals and were partially or completely ossified in large-sized individuals. The degree of ossification varied in the operculum, basibranchial II, and ascending process of the palatoquadrate. However, ossification was not associated with body size. The lacrimal, ossified manus, and ossified pes exhibited varying degrees of articulation or fusion irrespective of body size. Moreover, the cranium and tarsus of H. setouchi exhibited several unique characteristics. These osteological characteristics will aid in revising the taxonomy and phylogeny of the Hynobius species.
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intraspecific variation in the external and skeletal morphology of hynobius setouchi matsui okawa tanabe et misawa 2019 amphibia urodela Hynobiidae
Zoological Science, 2020Co-Authors: Sotaro Hara, Kanto NishikawaAbstract:The hynobiid salamander genus Hynobius is a basal taxon in the urodeles that plays a key role in understanding the evolution of sexual dimorphism in urodeles. We examined the age (juveniles vs. adults) and sexual differences in the external and skeletal morphology of a Japanese lentic breeding salamander, Hynobius setouchi. We found that juveniles had larger heads than those of adults, and most characters were larger in adult males than in females, except for trunk size. This was also observed in skeletal morphology, although some tail characters differed only in the skeleton. We suggest that intra- and interspecific comparisons of the external and skeletal characters of salamanders should consider age, sexual, and seasonal differences.
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a revision of hynobius stejnegeri a lotic breeding salamander from western japan with a description of three new species amphibia caudata Hynobiidae
Zootaxa, 2019Co-Authors: Atsushi Tominaga, Masafumi Matsui, Shingo Tanabe, Kanto NishikawaAbstract:A lotic-breeding salamander Hynobius stejnegeri, formerly called H. yatsui, from western Japan is revised based on genetic and morphological evidence, and three species are described: H. guttatus sp. nov. from Chubu-Kinki districts of Honshu Island, H. tsurugiensis sp. nov. from east highland of Shikoku Island, and H. kuishiensis sp. nov. from other parts of Shikoku Island. Thus, H. stejnegeri sensu stricto is restricted to Kyushu Island. Of these four species, H. kuishiensis sp. nov. contains two distinct mitochondrial lineages, but this split is not reflected in differentiation of allozyme (nuclear genome) markers. These species are morphologically similar to each other but can be differentiated by several characteristics, especially in combination of dorsal coloration, the number of vomerine, upper, and lower jaw teeth, and depth of vomerine teeth series. In coloration, H. guttatus sp. nov. is brown or dark brown mostly with tiny white to brownish white marking, while H. tsurugiensis sp. nov. is dark brown with bright yellow continuous markings. Hynobius kuishiensis sp. nov. is reddish purple or dark brown with small to continuous brownish white markings, in contrast to reddish purple or dark brown with small to large brownish white markings in H. stejnegeri.
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systematics of the widely distributed japanese clouded salamander hynobius nebulosus amphibia caudata Hynobiidae and its closest relatives
Current Herpetology, 2019Co-Authors: Masafumi Matsui, Kanto Nishikawa, Natsuhiko Yoshikawa, Gen Aoki, Shingo Tanabe, Yasuchika Misawa, Hiroshi Okawa, Koshiro Eto, Atsushi TominagaAbstract:The abundant clouded salamander from western Japan, Hynobius nebulosus, has long been considered a single widespread species, although some authors have suggested the inclusion of several cryptic species. This led to a molecular and morphological analysis of populations from all parts of the known range. Phylogenetic relationships were inferred from complete sequences of the mitochondrial cytochrome b gene, and nuclear genome differentiations were estimated by multiplexed inter simple sequence repeat genotyping by sequencing (MIG-seq). The results suggest that H. nebulosus hitherto recognized consists of at least nine species. We applied existing names to two of them, H. nebulosus (Temminck et Schlegel) and H. vandenburghi Dunn, and described seven others as new species.
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two new species of lotic breeding salamanders amphibia caudata Hynobiidae from western japan
Zootaxa, 2019Co-Authors: Atsushi Tominaga, Masafumi Matsui, Kanto NishikawaAbstract:Two new species of lotic-breeding salamanders, Hynobius sematonotos and H. oyamai, are described from Chugoku district and northeastern Kyushu district, respectively, western Japan. They are members of the so-called H. naevius group and are phylogenetically close to H. naevius, H. katoi, and H. hirosei but divergent from them with large genetic distances. These new species have been treated as Chugoku and northeastern Kyushu lineages, respectively, of H. naevius to which they are morphologically very similar. However, these new species can be differentiated from H. naevius by several morphological traits. Hynobius sematonotos is characterized and discriminated from other species by combination of small body size, a shallow vomerine teeth series with small number of vomerine teeth, small number of upper and lower jaw teeth, relatively long head and snout, and large upper eyelid, relatively short axilla-groin, reddish purple ground color with grayish brown marking on the dorsum, and reddish to bluish gray ventral ground color with relatively large markings varying from pale-white to white. Hynobius oyamai is characterized and discriminated from other species by large body size, moderately deep vomerine teeth series with a medium number of vomerine teeth, large number of upper and lower jaw teeth, relatively wide internarial and long fifth toe, bluish purple ground color sometimes with pale white marking on dorsum. Hynobius sematonotos occurs in Honshu, disjunct from H. naevius and H. oyamai that occur allopatrically in Kyushu.
Masato Hasumi - One of the best experts on this subject based on the ideXlab platform.
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effects of controlled water temperatures on oviposition in a lotic breeding and externally fertilizing salamander hynobius kimurae
River Research and Applications, 2017Co-Authors: Masaichi Kakegawa, Masato HasumiAbstract:Warm or cool ambient temperatures during winter generate plasticity in the within-year timing of oviposition or breeding phenology shifts through the use of a reaction norm in many riverine ectotherms, but within-year timing of oviposition in Hynobius kimurae (Caudata: Hynobiidae) is predicted to be constant at different water temperatures of a mountain stream. To clarify this difference, by experimentally controlling water temperatures from fall to spring and thus changing durations of aquatic hibernation and dates of oviposition, we determined whether oviposition is more advanced when water temperatures increase earlier than usual or is more delayed when water temperatures increase later than usual. Oviposition was more delayed than usual with earlier exposure to high water temperatures during spring and was earlier than usual with exposing to higher water temperatures during hibernation. Days from submergence to oviposition were responsive to cumulative daily water temperatures from submergence to oviposition within a population. A rate of increase in days from submergence to oviposition was different between populations but was constant within a population even if minimal water temperatures varied each year. When running a program of a Markov chain Monte Carlo generalized linear mixed model for Bayesian computation to interpret confounding effects, neither different treatments nor different years statistically affected days from submergence to oviposition. These results suggest that a biological clock exits for days from submergence to oviposition in H. kimurae, which could allow survival in situations with either warmer or cooler environments.
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Seasonal changes in body shape and mass in a lotic-breeding and externally fertilizing salamander Hynobius kimurae
Zoologischer Anzeiger, 2017Co-Authors: Masaichi Kakegawa, Fujio Kishi, Yuko Saikawa, Masato HasumiAbstract:Physiological condition linked to reproduction-related morphological traits (e.g., body mass, head width, tail height) is a key determinant of ecotypes related to fitness in ecological selection. In migratory salamanders such as the families Ambystomatidae (internal fertilization), Salamandridae (internal), and Hynobiidae (external), such morphological traits change at the transition between terrestrial and aquatic habitats. Unlike many other migratory salamanders, Hynobius kimurae (Hynobiidae) immigrates from land to water for aquatic hibernation during fall, and the immigration is not related to fall breeding. In this context, does fall immigration to water for winter dormancy induce changes in reproduction-related morphological traits? We analyzed changes in body shape and mass concurrent with physiological condition of 244 males and 131 females of H. kimurae with only data on first capture during fall and spring from 1996 to 2016. Although reproduction-related morphological traits in other migratory salamanders change simultaneously when they enter the water and subsequently initiate breeding during either season of fall–spring, such changes occurred both in male and female H. kimurae firstly during fall (shortly after entering the water) and secondly during spring (shortly after awaking from hibernation), except for head width being static throughout seasons. The differences suggest that these two-step changes during a prolonged period from fall to spring would be concentrated in a short period of breeding activity during either season of fall–spring in other migratory salamanders without hibernating in the water. As sexually selected, sexual dimorphism was detected in size and shape, especially shape of the tail, both height and length of which were greater in males than in females regardless of the sexes being terrestrial or aquatic. The male’s larger tail during the terrestrial phase may be a stock for a more developed tailfin (amount of reproductive output) in the aquatic-phase male potentially related to fitness.
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Age and body size of Salamandrella keyserlingii (Caudata: Hynobiidae): a difference in altitudes, latitudes, and temperatures
Organisms Diversity & Evolution, 2012Co-Authors: Masato Hasumi, Leo J. BorkinAbstract:The debate surrounding Bergmann’s rule, in which the body size of animals is predicted to be larger in cooler environments, is still open concerning ectotherms. Our goal was to test this rule in the broadest ranging amphibian species Salamandrella keyserlingii . We determined age and body size in a cooler region (Darhadyn, Mongolia: mean yearly air temperature = –8.31 °C) using skeletochronology, and compared their differences in altitude, latitude, and temperature with those of a warmer area (Kushiro, Japan: 7.98 °C). In Darhadyn, both sexes reached sexual maturity at 5–6 years of age (growth coefficient: male = 0.585, female = 0.266), 2–3 years later than those in Kushiro (male = 1.341, female = 1.129). Mean body size was smaller in Darhadyn (53.08 mm) than in Kushiro (57.63 mm) for males despite their constant metamorphic size around 30 mm. We also analyzed data available from published studies for 27 populations within the geographic range of this species from 43 to 69°N across a 2,900-km long latitudinal gradient. The analysis indicated an intraspecific tendency to decrease body size with increased latitude from 43 to 57°N, to increase size from 57 to 69°N, and to decrease body size with decreased temperature from 8 to –7 °C and increase size from –7 to –15 °C. This pattern does not follow the intraspecific extension of Bergmann’s rule and may follow the converse of Terentjev’s optimum rule—a rule formulated to be an inverted-U shaped curve between increased latitude (or decreased temperature) and increased body size.
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Age, Body Size, and Sexual Dimorphism in Size and Shape in Salamandrella keyserlingii (Caudata: Hynobiidae)
Evolutionary Biology, 2010Co-Authors: Masato HasumiAbstract:In organisms with determinate growth, sexual size dimorphism (SSD) occurs before maturity during the developmental process of growing apart, an ontogenetic perspective on the evolution of SSD. If the direction of SSD (female-larger SSD) is known, patterns of growth can be tested with one-tailed statistical distributions. In indeterminate growing organisms as well, does SSD occur before maturity? If it occurs, whether is females’ larger mean body size caused by a difference in age at maturity, age-specific size, divergent growth prior to maturity, or selection on post-maturational growth? How important is biphasic, sexual shape dimorphism (BSSD) for determinants of SSD? Biphasic characteristics are those that differ between adult aquatic- and terrestrial-phase morphs, and shape is size of a characteristic relative to body size. To address those questions, I determined age and body size based on a careful description of a growth trajectory for each sex in Salamandrella keyserlingii , using 555 independent data points from skeletochronological studies. Females reached maturity at 3–4 years of age, a year later than males that reached maturity at 2–3 years of age (mean body size: males = 57.63 mm, females = 61.70 mm; delayed sexual maturity resulted in SSD). However, SSD was highly detected before maturity (SSD index = 0.097), and females after maturity continued to grow and resulted in larger asymptotic size than males. Traits of BSSD were greater in males than in females. These results suggest that when determining SSD the difference in mean adult-body size results from the difference in age-specific size and the female-larger SSD develops to resolve intersexual ontogenetic conflict by allowing small-sized males to swell their whole body during the aquatic phase as much as large-sized females.
Mi-sook Min - One of the best experts on this subject based on the ideXlab platform.
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driven to the edge species distribution modeling of a clawed salamander Hynobiidae onychodactylus koreanus predicts range shifts and drastic decrease of suitable habitats in response to climate change
Ecology and Evolution, 2021Co-Authors: Mi-sook Min, Yucheol Shin, Amael BorzeeAbstract:Climate change is one of the major threats to global amphibian diversity, and consequently, the species distribution is expected to shift considerably in the future. Therefore, predicting such shifts is important to guide conservation and management plans. Here, we used eight independent environmental variables and four representative concentration pathways (RCPs) to model the current and future habitat suitability of the Korean clawed salamander (Onychodactylus koreanus) and then defined the dispersal limits of the species using cost distance analysis. The current habitat suitability model generated using the maximum entropy algorithm was highly consistent with the known distribution of the species and had good predictive performance. Projections onto years 2050 and 2070 predicted a drastic decrease of habitat suitability across all RCPs, with up to 90.1% decrease of suitable area and 98.0% decrease of optimal area predicted from binary presence grids. The models also predicted a northeastward shift of habitat suitability toward high-elevation areas and a persistence of suitability along the central ridge of the Baekdudaegan Range. This area is likely to become a climatic refugium for the species in the future, and it should be considered as an area of conservation priority. Therefore, we urge further ecological studies and population monitoring to be conducted across the range of O. koreanus. The vulnerability to rapid climate change is also shared by other congeneric species, and assessing the impacts of climate change on these other species is needed to better conserve this unique lineage of salamanders.
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the complete mitochondrial genome information of hynobius unisacculus amphibia caudata Hynobiidae and the phylogenetic implication
Mitochondrial DNA Part B, 2019Co-Authors: Ho Young Suk, Dongyoung Kim, Sunho Cha, Mi-sook MinAbstract:Hynobius unisacculus is a hynobiid salamander species found only in a limited area at the southernmost part of the Korean Peninsula. Here, we characterized the complete mitochondrial genome of this...
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phylogenetic structure and ancestry of korean clawed salamander onychodactylus koreanus caudata Hynobiidae
Mitochondrial DNA, 2018Co-Authors: Ho Young Suk, Mu-yeong Lee, Hang Lee, Nikolay A Poyarkov, Hangyu Bae, Seojin Stacey Lee, Mi-sook MinAbstract:Onychodactylus koreanus, a hynobiid salamander species endemic to the Korean Peninsula, can be regarded as a strict ecological specialist, probably vulnerable to anthropogenic environmental modifications and climate change. We used mitochondrial cytochrome b gene to analyze the genetic diversity and phylogenetic structure of O. koreanus from 19 populations collected in an attempt to cover its major distribution within South Korea. A total of 76 haplotypes of O. koreanus obtained in our analyses could be subdivided into three phylogenetic clades, KR, NE and SE. Clade KR haplotypes occur in most of the regions throughout the Korean Peninsula with four distinct subclades (KR I-IV). Clade NE and SE haplotypes were only observed in two populations YY and YS, respectively. Haplotype sharing was scarce even among populations in geographical proximity, and most of the populations were represented by a single clade or subclade, indicating the low level of gene flow among populations. O. koreanus likely originated from the historical southward dispersal of its ancestral lineages following divergence from Chinese O. zhaoermii that was recovered as the sister of O. koreanus in our phylogenetic analysis. Our results have critical implications for the taxonomic status of O. koreanus and its long-term management plan.
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a new species of salamander of the genus hynobius amphibia caudata Hynobiidae from south korea
Zootaxa, 2016Co-Authors: Mi-sook Min, Hae-jun Baek, Min Ho Chang, Jaeyoung Song, Nikolay A PoyarkovAbstract:We describe a new species of lentic-breeding Hynobius salamander from the Naro Islands, near the village of Bongrae-myeon, Goheung-gun, Jeollanam-do, South Korea, on the basis of results of morphological, ecological and genetic analyses. Hynobius unisacculus sp. nov. is distinguished from its congeners by a combination of the following morphological attributes: (1) comparatively small size (adult SVL up to 61 mm; range 38.3–60.3 mm in males and 37.5–59.9 mm in females); (2) relatively slender short limbs; tips of fore- and hindlimbs adpressed on body never meeting, but separated by a large gap (gap of -3.0 to -1.5 costal folds in males and -3.5 to -1.5 in females); (3) comparatively short tail (TL/SVL ratio in adult males varying from 0.54–0.98, in adult females from 0.55 to 0.89), tail flattened and with a low dorsal fin extending to the posterior one-third of tail length; (4) usually 11 (occasionally 12) costal grooves; (5) in adults, dark brown dorsum with indistinct bronze or dark copper spots, lighter greyish-white or pinkish belly; (6) well developed fifth toe; (7) comparatively shallow vomerine tooth series with 13–23 vomerine teeth; (8) small, pigmented ova, located in one, occasionally two, strings in a small, curved egg sac with folded envelope, lacking distinct mucous stalks or whiptail-like structures on both ends. The molecular differentiation among Korean Hynobius is high; Hynobius unisacculus sp. nov. is genetically highly divergent from the morphologically similar H. leechii , H. yangi and H. quelpaertensis : pairwise distances are 9.7%, 9.1% and 8.0% of sequence divergence at the COI mtDNA gene respectively, and 10.9%, 10.9% and 9.4% of sequence divergence at the cyt b mtDNA gene, respectively. At present, the new species is known from coastal areas and offshore islands in southeastern part of Jeollanam-do in South Korea. We suggest the species should be considered as Vulnerable (Vu2a) in accordance with IUCN’s Red List categories. Our study supports the presence of undiagnosed taxonomic diversity among Korean Hynobius .
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review of the systematics morphology and distribution of asian clawed salamanders genus onychodactylus amphibia caudata Hynobiidae with the description of four new species
Zootaxa, 2012Co-Authors: Nikolay A Poyarkov, Koji Iizuka, Mi-sook Min, Masaki Kuroo, Jing Che, Fang Yan, David R VieitesAbstract:We describe four new species of Asian Clawed salamanders of the genus Onychodactylus (Caudata: Hynobiidae), basedon fresh material collected during fieldwork in Japan, Korea, the Russian Far East and northeastern China between 2003and 2010, as well as older voucher specimens deposited in several museums. Our analyses comprise all species currentlyrecognized within this genus across its entire distribution range. We follow an integrative taxonomic approach bycombining detailed morphological comparative analyses with molecular phylogenetic analyses. We find significantdifferences among species in this genus, based on morphological and molecular data, which resulted in the recognitionand description of four new species within this genus. The new species have uncorrected molecular divergences of over4.5–7.4% and 1.9–4.1% to their closest relatives in the mitochondrial COI and 16S rRNA genes respectively. In themolecular analyses, we found two very divergent lineages in Korea and Japan that need further investigation, as detailedmorphological data are not available for them. We also discuss our approach to delimit species on salamanders. For thenew species described in this group we evaluate their threat status according to IUCN criteria: O. koreanus sp. nov. Min,Poyarkov & Vieites and O. nipponoborealis sp. nov. Kuro-o, Poyarkov & Vieites are classified as Least Concern, while O. zhaoermii sp. nov. Che, Poyarkov & Yan and O. zhangyapingi sp. nov. Che, Poyarkov, Li & Yan are classified as Vulnerable (Vu2a).
Natsuhiko Yoshikawa - One of the best experts on this subject based on the ideXlab platform.
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systematics of the widely distributed japanese clouded salamander hynobius nebulosus amphibia caudata Hynobiidae and its closest relatives
Current Herpetology, 2019Co-Authors: Masafumi Matsui, Kanto Nishikawa, Natsuhiko Yoshikawa, Gen Aoki, Shingo Tanabe, Yasuchika Misawa, Hiroshi Okawa, Koshiro Eto, Atsushi TominagaAbstract:The abundant clouded salamander from western Japan, Hynobius nebulosus, has long been considered a single widespread species, although some authors have suggested the inclusion of several cryptic species. This led to a molecular and morphological analysis of populations from all parts of the known range. Phylogenetic relationships were inferred from complete sequences of the mitochondrial cytochrome b gene, and nuclear genome differentiations were estimated by multiplexed inter simple sequence repeat genotyping by sequencing (MIG-seq). The results suggest that H. nebulosus hitherto recognized consists of at least nine species. We applied existing names to two of them, H. nebulosus (Temminck et Schlegel) and H. vandenburghi Dunn, and described seven others as new species.
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historical demography of an endangered salamander ranodon sibiricus amphibia urodela Hynobiidae a reassessment
Zoological Science, 2017Co-Authors: Kanto Nishikawa, Tatjana Dujsebayeva, Natsuhiko Yoshikawa, Masafumi Matsui, Atsushi TominagaAbstract:Chinese populations of the endangered Siberian salamander Ranodon sibiricus are reported to have diverged only about 120 years ago, and to have the lowest genetic diversity of any amphibian. However, these conclusions require verification, as the main range of the species is in Kazakhstan. Moreover, the generation time used for estimating divergence time has a weak ground. In order to clarify these problems, we investigated the molecular phylogenetic relationship and historical demography of the species covering its whole distribution range using the mitochondrial DNA region reported for Chinese population (1072 bp sequences of the control region), while conducting skeletochronological analysis to estimate accurate generation time. As a result, the range expansion was estimated at 88,000–50,000 YA, based on the generation time of 6–10 years. Degree of intraspecific genetic differentiation is actually very small, but, as a single species, is not so small as had been reported for Chinese population alone.
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two new salamanders of the genus onychodactylus from eastern honshu japan amphibia caudata Hynobiidae
Zootaxa, 2014Co-Authors: Natsuhiko Yoshikawa, Masafumi MatsuiAbstract:We describe two new species of hynobiid salamanders in the genus Onychodactylus from eastern Honshu, Japan, based on the morphological and genetic evidence. Onychodactylus intermedius sp. nov. is distributed in southern part of Tohoku District and northern Ibaraki and Niigata Prefectures, and was previously reported as S-Tohoku group. Onychodactylus intermedius belongs to the O. japonicus species complex, and differs from the other congeners in having relatively long tail, narrow head, short snout, 18 presacral vertebrae, and distinctly curved vomerine tooth series without gap. Onychodactylus fuscus sp. nov. is known from only four localities in Fukushima and Niigata Prefectures of Tohoku and Hokuriku Districts. It also belongs to the O. japonicus complex, but lacks the dorsal stripe, which is a diagnostic character of the species complex. In other characteristics, O. fuscus differs from the other congeners in having comparatively long tail, wide head and internarial space, shallowly curved vomerine tooth series with gap, and relatively few vomerine teeth. Both species described here breed in winter. Phylogenetically, the two new species are closely related to each other, forming a well-supported clade with O. tsukubaensis as their sister species. Onychodactylus intermedius sp. nov. is known to be parapatric with O. japonicus and O. nipponoborealis without hybridization, whereas O. fuscus sp. nov. is sympatric with O. japonicus at least in a single known locality, and analysis of microsatellite loci indicates they are reproductively isolated.
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genetic structure and cryptic diversity of onychodactylus japonicus amphibia caudata Hynobiidae in northeastern honshu japan as revealed by allozymic analysis
Zoological Science, 2012Co-Authors: Natsuhiko Yoshikawa, Masafumi Matsui, Kanto NishikawaAbstract:We conducted a comprehensive allozymic analysis of 393 specimens of the Japanese clawed salamander, Onychodactylus japonicus, from 33 populations of northeastern Honshu, Japan. As a result, these populations exhibited extensive geographic genetic differentiation, and four major genetic groups (N-Tohoku, S-Tohoku, Tsukuba, and SW-Honshu groups) were consistently recognized. Of these, the Tsukuba group was geographically isolated from all the others, whereas the N- and S-Tohoku groups, and the S-Tohoku and SW-Honshu groups, respectively, were nearly parapatric, without distinct geographic barriers. The magnitude of genetic distances between the four groups, except for between the N- and S-Tohoku groups, was as large as that normally found among different hynobiid species. A structure analysis detected no admixture of the N- and S-Tohoku groups, whereas few hybrids were found between the S-Tohoku and SW-Honshu around their contact zone. However, genetic exchange between these parapatric groups appeared to be infrequent, suggesting the presence of some isolation mechanisms between them. Within each group, only the S-Tohoku group exhibited an extensive level of population genetic structure that roughly distinguishes the eastern, central, and northwestern subgroups, indicating the complexity of the phylogeographic traits of this group. These results strongly suggest that populations of O. japonicus from northeastern Japan encompass several cryptic species.
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invalidity of hynobius yunanicus and molecular phylogeny of hynobius salamander from continental china urodela Hynobiidae
Zootaxa, 2010Co-Authors: Kanto Nishikawa, Atsushi Tominaga, Masafumi Matsui, Jianping Jiang, Jongbum Kim, Xiao Hong Chen, Natsuhiko YoshikawaAbstract:Based on morphological and molecular analyses, Xiong et al . (2007) synonymized Hynobius yunanicus Chen et al . with Pachyhynobius shangchengensis Fei et al ., both from continental China. Their study, however, was not substantial enough in that morphology of types of neither species was compared, only a partial mitochondrial cytochrome b (cyt b) sequence was employed, and data for H. chinensis was lacking. In order to reassess their conclusion, we morphologically examined type specimens of both species, and compared their complete cyt b (1141 bp) sequences, together with all the six recognized continental Hynobius species and some congeners from Japan and South Korea.