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A crocodile newt, Echinotriton raffaellii, recently described from the Amami islands in the Ryukyu archipelago, western Japan has been regarded as Amami lineage of E. andersoni from the Okinawa islands, to which it is morphologically very similar, but genetically divergent. In the original description of E. raffaellii, only two specimens, including one born in captivity, were examined and only limited morphological comparisons with E. andersoni were made. Here we examined the morphological characteristics of E. raffaellii with an ample set of specimens, compared them with those of E. andersoni, and clarified their independent specific statuses.

Previous phylogenetic studies based on mitochondrial DNA data have consistently suggested that Hynobius tokyoensis consists of two major clades, clade A (northern clade) and clade B (southern clade). In this study, we newly estimated their population genetic structure and phylogenetic relationships by nuclear SNPs, and the results suggested heterospecific relationships of the two mitochondrial clades, without present hybridization in between. They were also recognized as morphologically different. The type locality of H. tokyoensis is in Tokyo Prefecture, and therefore clade B corresponds to H. tokyoensis sensu stricto, leaving clade A without available scientific name. We, thus, describe the clade A from northeastern Kanto to southern Tohoku as a new species Hynobius sengokui. The new species is distinguished from H. tokyoensis by its relatively longer axilla-groin distance, shorter trunk, and deeper vomerine teeth series, and is estimated to have diverged from it during the late Pliocene.

Herein, we provided a morphological description combined with a phylogenetic analysis of the northernmost Thai Tylototriton population, which was found in Doi Pha Hom Pok National Park (DPHPNP), Chiang Mai Province, northern Thailand. Three adult males were collected from a small breeding pond during our survey in July 2020. Based on molecular (two specimens) and morphological (three specimens) evidence, all three specimens from DPHPNP were identified as Tylototriton verrucosus Anderson, 1871, and were characterized by having a blackish background, orange to light orange-brown color markings, segmented vertebral ridge, prominent rib nodules ranging from 13–15 warts, and a rough skin with granules. Hence, this second record of T. verrucosus populations in Thailand confirms a range extension of this species in northern Indochina. Additionally, the morphological variation and conservation status are discussed for the populations from Thailand.

The development of lotic-breeding Bufo torrenticola is described from zygote to completion of metamorphosis in captivity at 13±1°C. We delimit 56 developmental stages based on external features. We describe developmental stages so as to be comparable to common stages that are widely used for anurans. We also compare the larval development between B. torrenticola in lotic water and lentic water, and with lentic-breeding B. japonicus formosus in lentic water. Our results suggest tadpole mouth size in B. torrenticola is determined by genetic factors, but the tail muscle volume is determined by both genetic and environmental factors., 流⽔産卵性ナガレヒキガエルと⽌⽔産卵性アズマヒキガエルの個体発⽣比較 --渓流適応したヒキガエルの発生の実態に迫る--. 京都大学プレスリリース. 2022-03-01.

We describe a new species of the newt genus Tylototriton from Umphang Wildlife Sanctuary, Tak Province, western Thailand based on molecular and morphological evidence and named here as Tylototriton umphangensissp. nov. The new species is assigned to the subgenus Tylototriton and differs from other species in having dark-brown to blackish-brown body and limbs, truncate snout, prominent antero-medial ends of the expansion of the dentary bones, laterally protruding quadrate regions, indistinct and small rib nodules, a well-segmented vertebral ridge, and rough dorsolateral bony ridges, which are steeper anterior, and curved medially at the posterior ends. The molecular data show that Tylototriton umphangensissp. nov. differs from T. uyenoi sensu stricto by a 5% genetic sequence divergence of the mitochondrial NADH dehydrogenase subunit 2 region gene. The new species and T. uyenoi are both endemic to Thailand, distributed along the Northwest Thai (Dawna) Uplands of Indochina. To clarify the species boundary between Tylototriton umphangensissp. nov. and T. uyenoi, additional field research is needed in adjacent areas. Tylototriton umphangensissp. nov. is restricted to evergreen hill forests in Umphang Wildlife Sanctuary. We suggest that the new species should be classified as Endangered (EN) in the IUCN Red List.

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.

Species identification using molecular techniques has recently become common for various taxa. Loop-mediated isothermal amplification (LAMP) is one of the easiest and least expensive molecular identification methods. Although few studies have developed LAMP assays for amphibians, we believe that LAMP is also useful for identifying endangered amphibians. Hynobius tokyoensis and H. lichenatus occur in Honshu, Japan, and have parapatric distributions. They are similar morphologically, especially at early developmental stages, including eggs and larvae. Hynobius tokyoensis has been listed as a national endangered species in Japan since 2020, and unambiguous identification of these species is therefore important for their conservation and management. In this study, we developed a LAMP primer set for the mitochondrial cytochrome b region to detect H. tokyoensis, and we evaluated the LAMP assay using total genomic DNA from four H. tokyoensis and three H. lichenatus individuals from across most of their ranges. Our LAMP primer set could distinguish these two species. This study should help to establish LAMP assays for other endangered species and morphologically similar species., 希少種のサンショウウオの簡易DNA判別が可能に --違法売買防止への大きな一手--. 京都大学プレスリリース. 2021-11-15.

The genus Kalophrynus is represented by tiny to medium terrestrial or subfossorial frogs and is widely distributed in Southeast Asia. The diversity centre of this genus is Borneo, where almost half of all nominal species are distributed and all of these are endemic to this and the peripheral islands. Kalophrynus nubicola is the smallest species within this genus; it is found only at high elevations in Gunung Mulu National Park, northeastern Sarawak, Malaysian Borneo. Three groups of populations were preliminary reported, but taxonomic decision on the groups was not yet given. In this study, we investigated the morphological, acoustic, and genetic differences among these three populations to reassess their taxonomic status. Morphological analyses confirmed differences in body size and colouration, molecular analyses indicated that each group was monophyletic, and differences in the acoustic characteristics of each group were also diagnostic. Therefore, herein, we describe them as distinct taxa. Phylogenetic analyses revealed that the K. nubicola group forms a highly divergent clade from other species within the genus. Our findings reveal that seven Kalophrynus species occur in Gunung Mulu National Park, with non-overlapping distributions according to elevation or forest type. We further discuss the biogeography and evolutionary history of this species group.

The new nematode species, Falcaustra hanzaki n. sp. and Urodelnema takanoensis n. sp. (Cosmocercoidea: Kathlaniidae), were found from the intestine of giant salamanders in Kyoto Prefecture, Japan. The first species is featured by the number and arrangement of caudal papillae (3 pairs of precloacal papillae, 8 pairs of postcloacal papillae and a single ventral precloacal papilla), the presence of a single pseudosucker, spicules equal in size (520-638 μm long), and V-shaped gubernaculum in males; vulva situated about 3/5 of a body in females. The second species is characterized by the number and arrangement of caudal papillae (5 pairs of precloacal papillae, 6 pairs of postcloacal papillae and a single ventral precloacal papilla), spicules equal in size (403-593 μm long), V-shaped gubernaculum in males; vulva situated about 3/5 of a body in females. The molecular phylogenetic analysis was performed using the partial 18S and 28S ribosomal DNA and the internal transcribed spacers 1 region in the nuclear DNA. This phylogenetic study raised a question about the validity of Family Kathlaniidae and related families of Cosmocercoidea.

Viviparous reproduction has evolved independently more than 100 times in the evolutionary history of Squamata (lizards and snakes). Adaptation to cold climates is the dominant hypothesis explaining...

The jaws of vertebrates display a striking diversity in form and function, but they typically open and close like a trapdoor rather than sliding like a saw. Here, we report unique feeding behaviour in the blunt-headed snail-eating snake, Aplopeltura boa (family Pareidae), where the snake cuts off and circumvents the indigestible part (the operculum) of its prey in the mouth using long sliding excursions of one side of the mandible, while the upper jaws and the mandible on the other side maintain a stable grasp on the prey. This behaviour, which we call ‘mandibular sawing’, is made possible by extraordinarily independent movements of the jaw elements and is a surprising departure from usual feeding behaviour in vertebrates., ヘビが顎をノコギリのように使うことを発見 --ボルネオ島での爬虫両生類の生態調査で--. 京都大学プレスリリース. 2020-07-31.

Females of some Asian salamanders of the genus Hynobius deposit in streams their eggs embedded in a translucent envelope called an 'egg sac'. The edges of the envelope exhibit a spectacular blue-to-yellow iridescent glow, which instantaneously disappears when the sac is removed from water. First, our scanning electron microscopy analyses reveal that the inner surface of the 100 μm-thick envelope displays striations (length scale of about 3 μm), which are themselves covered by much smaller (190 ± 30 nm) and quasi-periodic corrugations. The latter could constitute a surface diffraction grating generating iridescence by light interference. Second, our transmission electron microscopy and focused-ion-beam scanning electron microscopy analyses show that the bulk of the egg sac wall is composed of meandering fibres with a quasi-periodic modulation of 190 ± 60 nm along the thickness of the envelope, generating a photonic crystal. Third, Fourier power analyses of 450 electron microscopy images with varying incident angles indicate that changing the surrounding medium from water to air shifts most of the backscattered power spectrum to the ultraviolet range, hence, explaining that the egg sac loses visible iridescence when removed out of the water. Fourth, the results of our photography and optical spectroscopy experiments of submerged and emerged egg sacs rule out the possibility that the iridescence is due to a thin film or a multilayer, whereas the observed non-specular response is compatible with the backscattering expected from surface diffraction gratings and volumetric photonic crystals with spatial 1D modulation. Finally, although we mention several potential biological functions of the egg sac structural colours and iridescence, we emphasise that these optical properties might be the by-products of the envelope material internal structure selected during evolution for its mechanical properties.

Competition within and among species can play a key role in structuring the assemblages of anuran tadpoles. Previous studies have reported that tadpoles of the invasive cane toad (Rhinella marina) are more strongly disadvantaged by the presence of native frog tadpoles than by the same number of conspecific toad tadpoles. That effect might arise from a lack of coevolution of the invasive toad with its competitors; and/or from a generalized superiority of frog tadpoles over toad tadpoles. To clarify those possibilities, we conducted experimental trials using the larvae of a native rather than invasive toad (Bufo japonicus formosus in Japan) exposed to larvae of native anurans (the sympatric frogs Rana japonica and Rana ornativentris and the parapatric toad Bufo japonicus japonicus). In intraspecific competition trials, higher densities of B. j. formosus prolonged the larval period and reduced size at metamorphosis, but did not affect survival. In interspecific competition trials, the effects of the other anuran species on B. j. formosus were similar to the effects of the same number of conspecific larvae. This similarity in impact of interspecific versus intraspecific competition argues against any overall competitive superiority of frog larvae over toad larvae. Instead, the vulnerability of larval cane toads to frog tadpoles may result from a lack of coevolutionary history.

The genus Rhabdias StilesHassall, 1905 comprises lung parasites of amphibians and reptiles worldwide. In Japan, 9 species have been recorded, including Rhabdias incerta Wilkie, 1930 which has been reported only in Bufo species. In this study, to assess the diversity of R. incerta, we performed molecular analyses of Rhabdias species sampled from three species/subspecies of Japanese toads namely Bufo japonicus, B. japonicus formosus, and B. torrenticola, collected in various regions of Honshu, Shikoku, and Kyushu, Japan. DNA sequence divergence was compared using mtDNA (COI) and nuclear DNA (28S) to identify possible cryptic species. Morphological analysis was performed through light microscopy and scanning electron microscopy (SEM). The results revealed that Bufo spp. serve as hosts for at least three Rhabdias species. Morphologically, most samples were identified as R. incerta but with a longer body and larger buccal cavity than originally described. Rhabdias incerta appears to be specific to the genus Bufo and is further subdivided into two or three phylogroups based on subspecies divisions and biogeography of their host. Some Rhabdias specimens collected in this study resemble R. tokyoensis Wilkie, 1930, parasitic in hosts from the order Caudata, which suggests host switching. Both molecular and morphological analyses suggested the presence of undescribed and cryptic Rhabdias species within toads collected in Japan. This study was the first to molecularly characterize Rhabdias species in Japan, including novel sequences of R. incerta and two undescribed species.

Background The climatic oscillations in the Quaternary period considerably shaped the distribution and population genetic structure of organisms. Studies on the historical dynamics of distribution and demography not only reflect the current geographic distribution but also allow us to understand the adaption and genetic differentiation of species. However, the process and factors affecting the present distribution and genetic structure of many taxa are still poorly understood, especially for endemic organisms to small islands. Methods Here, we integrated population genetic and ecological niche modelling approaches to investigate the historical distribution and demographic dynamics of two co-existing salamanders on Tsushima Island, Japan: the true H. tsuensis (Group A), and Hynobius sp. (Group B). We also examined the hypothesis on the equivalency and similarity of niches of these groups by identity and background tests for ecological niche space. Results Our result showed that Group A is considered to have undergone a recent population expansion after the Last Glacial Maximum while it is unlikely to have occurred in Group B. The highest suitability was predicted for Group A in southern Tsushima Island, whereas the northern part of Tsushima Island was the potential distribution of Group B. The results also suggested a restricted range of both salamanders during the Last Interglacial and Last Glacial Maximum, and recent expansion in Mid-Holocene. The genetic landscape-shape interpolation analysis and historical suitable area of ecological niche modelling were consistent, and suggested refugia used during glacial ages in southern part for Group A, and in northern part of Tsushima Island for Group B. Additionally, we found evidence of nonequivalence for the ecological niche of the two groups of the salamanders, although our test could not show either niche divergence or conservatism based on the background tests. The environmental predictors affecting the potential distribution of each group also showed distinctiveness, leading to differences in selecting suitable areas. Finally, the combination of population genetics and ecological modeling has revealed the differential demographic/historical response between coexisting two salamanders on a small island.

Four new water mite species of the genus Hygrobates, subgenus Lurchibates (Acari, Hydrachnidia, Hygrobatidae) are described. Hygrobates (Lurchibates) macrochela sp. nov. Goldschmidt, Nishikawa & Shimano is described in male and female; Hygrobates (Lurchibates) malosimilis sp. nov. Goldschmidt, Nishikawa & Shimano is described in male, both new water mite species were collected from newts of the species Pachytriton inexpectatus Nishikawa, Jiang, Matsui & Mo, 2011; Hygrobates (Lurchibates) incognitus sp. nov. Goldschmidt, Nishikawa & Shimano is described in female collected from newts of the species Paramesotriton guangxiensis (Huang, Tang and Tang, 1983); Hygrobates (Lurchibates) fragmentarius sp. nov. Goldschmidt, Nishikawa & Shimano is described in a single severely fragmented specimen (sex could not be determined) collected from a newt of the species Paramesotriton yunwuensis Wu, Jiang, and Hanken, 2010. Principal differences between the subgenus Lurchibates and the nominal subgenus Hygrobates s. str. are illustrated and discussed as well as the sexual dimorphism of Lurchibates. Morphometric analyses confirmed the morphological differences of ten out of the eleven so far described species (H. (L.) fragmentarius could not be included in the analysis); two morphological groups became evident mainly based upon the shape of the anterior coxae. These analyses as well provide an idea of possible phylogenetic relationships among the species. A key to all currently known species of the subgenus Lurchibates is given. So far the subgenus is restricted to SE-Asia, a map showing the distribution of all species is presented.

Taxonomic identification of two Taiwanese salamanders, Hynobius sonani (Maki, 1922), and H. formosanus Maki, 1922, was clarified. Based on the descriptions and measurement data in the original description, we confirmed that H. sonani has been treated as H. formosanus and vice versa, which might have been caused by confusion of sampling localities of the two species. Because we could not find the holotypes of the two species and concluded these were lost, we herein assign neotypes for these species for precluding future taxonomic confusion.

We determined the complete mitochondrial genome sequences of two water mites, Hygrobates (Hygrobates) longiporus and H. (Rivobates) taniguchii. The length of the entire mitogenome of these two species is 13,721 bp and 13,770 bp long, respectively. Both of them contain 13 proteins, two rRNAs, and 22 tRNAs for a total of 37 gene products. The gene order of Hygrobates is almost identical to the two species of Unionicola we included in the analysis, with some difference in the position of transfer RNA genes. Phylogenetic analyses highly support these Hygrobates species form a clade with other species of the Hygrobatoidea.

The Tsushima salamander, Hynobius tsuensis, is a lotic-breeding species endemic to Tsushima Island, Japan. We investigated genetic variation in this species using samples covering all known localities on the island. Phylogenetic analyses based on mitochondrial cytochrome b gene sequences divided H. tsuensis populations into two genetic groups: true H. tsuensis and an unknown species (Hynobius sp.) showing a closer relationship to Hynobius nebulosus than to H. tsuensis. The genetic distance between the two groups was greater than the genetic distances between different species of Hynobius. Both groups were found to breed in mountain streams, sometimes in the same streams syntopically. Population structure analysis based on several nuclear microsatellite loci strongly indicated reproductive isolation between the two groups in the syntopic localities. This is the first report confirming the syntopic occurrence of two lotic salamanders of Hynobius on a small island. We propose that the lotic breeding habits of the two salamanders were independently acquired.

We found a uniquely colored dicroglossid frog of the genus Occidozyga from western Sarawak, East Malaysia. It is divergent from other congeners in morphology and mtDNA sequences. In a molecular phylogeny, this species is the sister lineage to the continental species O. lima and O. martensii with weak support. The species is small with SVL 16–18 mm in males and 18–19 mm in females, without dorsolateral fold but with transverse wrinkles on dorsum, tips of fingers lacking disks but of toes with disks, only first and second toes webbed to disks, and orange-brown dorsum with dark brown band. We thus describe it as a new species.

Gunung Mulu National Park (GMNP) in northwestern Borneo is marked by high species diversity and diverse environments. We present one new amphibian and ten new reptile records from GMNP and its surrounding area. In the records, Asthenodipsas jamilinaisi and Garthius chaseni were newly recorded in the Sarawak State. We also present the first record of Cyrtodactylus muluensis from outside of GMNP and the second record of Opisthotropis typica from the park. Combined with previous information, a total of 108 amphibians and 104 reptiles are known from GMNP, and their preferred habitat types are diverse. Furthermore, observed male-male combat of Dopasia buettikoferi is the first detailed description of the genus. Two color morphs of D. buettikoferi had an identical ND2 haplotype and appeared to be the same species. The present study provides new information about Bornean amphibians and reptiles, and also emphasizes the importance of continuous monitoring.

The red-bellied form of Calliophis intestinalis (Laurenti, 1768) sensu lato was originally reported from Pahang, west Malaysia. To determine the taxonomic status of this form, we examined the type specimens of Elaps sumatranusLidth De Jeude, 1890, Calliophis intestinalis everetti (Boulenger, 1896), and Callophis furcatus var. nigrotaeniatusPeters, 1863. The results indicated that the red-bellied form of C. intestinalis should be named as Calliophis nigrotaeniatus comb. nov., whose valid species status was based on morphological and molecular analyses. We designate a lectotype and redescribe the species, which is genetically close to Calliophis bilineatus (Peters, 1881) from the Philippines, and is clearly distinguishable from other congeners by possessing a pair of gray or dark blue lateral stripes and by being bright red on the ventrum. Elaps sumatranus and C. i. everetti are relegated to subjective junior synonyms of C. nigrotaeniatus.

The Tsushima salamander

We surveyed the genetic structure of Hynobius nigrescens Stejneger, 1907, a lentic breeding salamander widespread throughout montane and lowland regions of northeastern Japan. We performed a mitochondrial DNA analysis to explore intraspecific genetic variation and infer the evolutionary population history of H. nigrescens. Complete 1141 bp sequences of the mitochondrial cytochrome b gene were studied for 134 adult and larval individuals collected from 62 localities, encompassing the known range of the species. Hynobius nigrescens proved to be monophyletic, including two major clades (Clade II from southwestern Hokuriku and Clade I from all other localities). The latter clade comprises four well-supported and geographically structured subclades, which show genetic distances smaller than those seen in the widely sympatric species Hynobius lichenatus. Results of population statistical analyses indicated that Clade II of the westernmost range of H. nigrescens seems to have maintained a constant population size, while Clade I from most of the northeastern species range shows a tendency of recent population expansion, which is evident in Subclades I-A from the northernmost range and I-B from southern Tohoku to northern Kanto and eastern Chubu. In contrast, Subclades I-C from northeastern Chubu and Sado Is. and I-D from northwestern Chubu to Hokuriku seem to have been relatively stable in population size. Hynobius nigrescens differs greatly from other salamander species from northeastern Japan in its much more recent periods of genetic differentiation and its pattern thereof, and is suggested to be a young faunal element in this region.

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