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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 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 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.

We investigated the phylogenetic relationships and estimated the history of species diversification and character evolution in two ichthyophiid genera: Caudacaecilia and Ichthyophis. We estimated the phylogenetic relationships of 67 samples from 33 localities in Southeast Asia from 3840-bp sequences of the mitochondrial 12S rRNA, 16S rRNA, and cyt b genes using Bayesian inference, maximum likelihood, and maximum parsimony methods. The Southeast Asian samples formed a well-supported clade differentiated from a South Asian sample. The Southeast Asian clade was divided into two subclades, one containing samples from South China, Indochina, Malay Peninsula, and Java. The other consisted of samples from Borneo and the Philippines. Neither Caudacaecilia nor Ichthyophis was monophyletic, nor did samples with or without light stripes lateral to the body form clades. We found several distinct sympatric lineages and undescribed species, especially from Sundaland.

We estimated the genealogical relationships and assessed systematic relationships among 45 out of 89 named species and four unnamed taxa from 11 of 14 genera of the Oriental microhylids from 1767 bp sequences of the mitochondrial DNA genes 12S rRNA and 16S rRNA using maximum parsimony, maximum likelihood, and Bayesian inference methods. Monophyly was rejected for the subfamily Microhylinae, and our data reveal four well-supported clades whose relationships to each other are unresolved: (A) Microhyla, Calluella, and Glyphoglossus, (B) Chaperina, (C) Kaloula, Phrynella, and Metaphrynella, and (D) Micryletta. They were genetically as divergent from each other as from another Oriental subfamily Kalophryninae, and could be recognized as distinct subfamilies. Within Clade A, our data reveal three well-supported subclades whose relationships to each other are unresolved: (AI) Microhyla-I, (AII) Calluella and Glyphoglossus, and (AIII) Microhyla-II. Of the two enigmatic Malaysian genera, whose subfamilial placement has been undetermined, Phrynella was found to be the sister species of Metaphrynella in Clade C, whereas Gastrophrynoides was grouped in the Papua-Australian subfamily Asterophryinae. Currently recognized subgenera and species groups within Microhyla based on morphology were not supported phylogenetically, and require thorough reassessments.

A survey of genetic variation of lotic breeding salamander Hynobius naevius by starch gel electrophoresis using 26 populations from southwestern Japan revealed the presence of two genetically distinct groups (GROUP-A and B) which overlap distributional ranges in some parts of Kyushu. Degree of genetic differentiation between the two groups was larger in Kyushu, including sympatric area, than in allopatric areas. We surmise that the two groups first differentiated allopatrically and overlapped their distributions secondarily. The first genetic differentiation is considered to have occurred in the Pliocene as a result of isolation between northern (GROUP-A) and southern (GROUP-B) ancestral populations by the formation of the Seto Inland Sea, largely separating the present distributions of the two groups. Genetic diversities within the GROUP-A seem to have become complicated by isolations, disappearances of local populations, and subsequent range expansion of distributions in Chugoku and northern half of Kyushu regions. Within the GROUP-B, diversities first formed by isolation by distance have been retained and accelerated secondarily by the formations of the Kii and Bungo straits. Sympatric populations of the two groups in northern half of Kyushu seem to have overlapped their ranges by niche segregation.

Taxonomic status of a salamander now identified as Hynobius tokyoensis from Aichi Prefecture, Japan, was assessed by allozymic comparisons with its relatives. All three populations of H. tokyoensis from Aichi formed a monophyletic group with populations of H. nebulosus; this group is substantially diverged from a conspecific population from Kanagawa that formed another group with H. lichenatus. In the former group, the population of H. nebulosus from near the type locality was more divergent from the other conspecific populations than were three populations of H. tokyoensis from Aichi. It is quite clear that the salamander from Aichi now identified as H. tokyoensis is genetically much closer to H. nebulosus than to H. tokyoensis from Kanagawa, which is closest geographically to its type locality. This result conforms well to reported results of morphological and genetic studies, and the salamander from Aichi, now called H. tokyoensis, should be identified as H. nebulosus, which is sufficiently diverged from H. tokyoensis to be considered a distinct species.