A new species of Cnemaspis Strauch (Squamata: Gekkonidae) of the C. siamensis group from Tenasserim Mountains, Thailand

An integrative taxonomic analysis recovered the new species Cnemaspis selenolagus sp. nov. of the C. siamensis group as the sister species to C. punctatonuchalis. The new species was discovered in mountain evergreen tropical forests of in Suan Phueng District of Ratchaburi Province, western Thailand. Additionally, the analysis recovered a deep genetic divergence between northern and southern clades within the C. siamensis group that occur on opposite sides of the Isthmus of Kra—a well-known biogeographic region of cladogenic turnover. The description of C. selenolagus sp. nov. brings the total number of species of Cnemaspis in Thailand to 16, 11 of which compose the C. siamensis group—a lineage endemic to the Thai-Malay Peninsula. This underscores the physiographic complexity of this narrow peninsula in that it can support a large number of closely related species in only the northern two-thirds of its length.

A new skink of the genus Subdoluseps (Hardwicke & Gray, 1828) from Peninsular Malaysia

An integrative taxonomic analysis of Subdoluseps herberti from southern Thailand and Peninsular Malaysia and S. samajaya from Sarawak, East Malaysia (Borneo) recovers the former as paraphyletic with respect to the latter. The analyses recover the three southernmost populations of S. herberti in Peninsular Malaysia as conspecific and the sister lineage of S. samajaya, whereas S. herberti from Thailand and northern Peninsular Malaysia constitute the sister species to S. samajaya plus the southern three Peninsular Malaysian populations. As such, the southern populations are described herein as S. malayana sp. nov. and all three species are referred to as the S. herberti group. Clade boundaries and breaks within this group on the Thai-Malay Peninsula occurring at the Isthmus of Kra, across the Kangar-Pattani line, and between the Thai-Malay Peninsula and Borneo are consistent with phylogeographic patterns of other Sundaic taxa. The discovery of S. malayana sp. nov. continues to underscore the fact that, despite the well-studied nature of the lizard fauna of Peninsular Malaysia, much of it still remains unrealized and for conservation efforts to move forward, field research followed by expeditiously revised taxonomies must continue.

Two new and potentially highly threatened Megophrys Horned frogs (Amphibia: Megophryidae) from Indochina’s highest mountains

Megophrys are a group of morphologically conserved, primarily forest-dependent frogs known to harbour cryptic species diversity. In this study, we examined populations of small-sized Megophrys from mid- and high elevation locations in the Hoang Lien Range, northern Vietnam. On the basis of morphological, molecular and bioacoustic data, individuals of these populations differed from all species of Megophrys known from mainland Southeast Asia north of the Isthmus of Kra and from neighbouring provinces in China. Further, the newly collected specimens formed two distinct species-level groups. We herein describe two new species, Megophrys fansipanensis sp. nov. and Megophrys hoanglienensis sp. nov. Both new species are range restricted and likely to be highly threatened by habitat degradation. These discoveries highlight the importance of the Hoang Lien Range for Vietnam’s amphibian diversity.

First record of the Malaysian Bridle Snake, Dryocalamus subannulatus (Duméril, Bibron & Duméril, 1854), in Myanmar (Reptilia, Serpentes, Colubridae)

Dryocalamus subannulatus is reported for the first time from Myanmar. A single individual was found on the Thayawthadangyi Island Group in the Myeik Archipelago, Tanintharyi Region. Morphological features and a maximum likelihood analysis of the 16S mitochondrial gene confirm its identity. This specimen represents the first record of D. subannulatus north of the Isthmus of Kra.

Phylogenetic relationships and genetic diversity of thePolypedates leucomystaxcomplex in Thailand

Taxonomic uncertainty of the Asian tree frogPolypedates leucomystaxcomplex presents the challenging task of inferring its biogeographical history. Here, we describe its dispersion and the genetic relationships among different populations in Thailand, where we connect the population of theP. leucomystaxcomplex of the Sunda Islands to the Indochina (mainland) population based on analyses of 266 sequences of the mitochondrial cytochrome c oxidase subunit I (COI) gene. Our maternal genealogy implies that there are four well-supported lineages in Thailand, consisting of Northern A (clade A:Polypedatessp.), Nan (clade B:P.cf.impresus), Southern (clade C:P. cf.leucomystax) and Northern D (clade D:P.cf.megacephalus), with Bayesian posterior probability >0.9. Phylogeny and haplotype networks indicate that clades A, B and D are sympatric. In contrast, clade C (P. cf.leucomystax) and clade D (P.cf.megacephalus) are genetically divergent due to the geographical barrier of the Isthmus of Kra, resulting in an allopatric distribution. Climatic conditions, in particular differences in rainfall on each side of the Isthmus of Kra, may play an important role in limiting the immigration of both clades. For the within-populations of either clades C or D, there was no significant correlation between geographic and genetic distance by the isolation-by-distance test, indicating intraspecific-dispersal of each clade. Population expansion occurred in clade C, whereas clade D showed a constant population. Taken together, theP. leucomystaxcomplex in South East Asia may have diversified under climatic pressure, leading to allopatric and/or sympatric speciation.

Troublesome Trimes: Potential cryptic speciation of the Trimeresurus (Popeia) popeiorum complex (Serpentes: Crotalidae) around the Isthmus of Kra (Myanmar and Thailand)

The taxonomic identity of the Trimeresurus (Popeia) popeiorum complex from the Isthmus of Kra and to the north was investigated. Several studies over the last decade have produced several specimens and associated mtDNA sequence data for a variety of individuals of the T. popeiorum and “T. sabahi” complexes. Here, we combine four mitochondrial genes (12S, 16S, ND4, and CytB) from all available specimens in GenBank with the addition of five new specimens collected from the mainland, Tanintharyi Region of Myanmar. Maximum Likelihood and Bayesian analyses identified that T. popeiorum sensu lato is paraphyletic with two geographically distinct clades: a northern clade representing populations from northern Myanmar, Laos and northern Thailand and a southern clade representing samples from the Tanintharyi Region and adjacent west Thailand. While the two clades have considerable genetic distance, they appear to be morphologically identical, leading to the hypothesis that the southern clade represents a cryptic, undescribed species. Because they appear to be cryptic species and the limitation of only five specimens from the southern lineage, this does not permit us to formally describe the new species. In accordance to past molecular studies, we uncovered paraphyly and lack of genetic support for the validity of taxa within the T. sabahi complex. However, we suggest recognizing these populations as subspecies within T. sabahi.

Phylogenetic relationships and genetic diversity of the Polypedates leucomystax complex in Thailand

Controversy in the taxonomic evaluation of the Asian tree frog Polypedates leucomystax complex presents the challenging task of gaining insight into its biogeographical distribution and diversification. Here, we describe the dispersion and genetic relationship of these species in Thailand where we connect the population of the P. leucomystax complex of the Sunda Islands to the mainland population based on the mitochondrial cytochrome c oxidase subunit I (COI) gene, derived from 266 samples. Our maternal genealogy implies that there are four well-supported lineages in Thailand, consisting of Northern A (clade A: Polypedates sp.), Nan (clade B: P. cf. impresus), Southern (clade C: P. cf. leucomystax) and Northern B (clade D: P. cf. megacephalus), with Bayesian posterior probability >0.9. Phylogeny and haplotype networks indicate that clades A, B and D are sympatric. In contrast, clade C (P. cf. leucomystax) and clade D (P. cf. megacephalus) are genetically divergent due to the geographical barrier of the Isthmus of Kra, resulting in allopatric distribution. Climatic conditions, in particular rainfall, that differ on each side of the Isthmus of Kra may play an important role in limiting the immigration of both clades. For the within-populations of either clades C or D, there was no significant correlation between geographic and genetic distance by the isolation-by-distance test, indicating intraspecific gene flow of each clade. Population expansion occurred in clade C, whereas clade D showed a constant population. Taken together, the P. leucomystax complex in Southeast Asia may be diversified by climatic oscillation, leading to allopatric and/or sympatric speciation.

Phylogenetic relationships and genetic diversity of the Polypedates leucomystax complex in Thailand

Controversy in the taxonomic evaluation of the Asian tree frog Polypedates leucomystax complex presents the challenging task of gaining insight into its biogeographical distribution and diversification. Here, we describe the dispersion and genetic relationship of these species in Thailand where we connect the population of the P. leucomystax complex of the Sunda Islands to the mainland population based on the mitochondrial cytochrome c oxidase subunit I (COI) gene, derived from 266 samples. Our maternal genealogy implies that there are four well-supported lineages in Thailand, consisting of Northern A (clade A: Polypedates sp.), Nan (clade B: P. cf. impresus), Southern (clade C: P. cf. leucomystax) and Northern B (clade D: P. cf. megacephalus), with Bayesian posterior probability >0.9. Phylogeny and haplotype networks indicate that clades A, B and D are sympatric. In contrast, clade C (P. cf. leucomystax) and clade D (P. cf. megacephalus) are genetically divergent due to the geographical barrier of the Isthmus of Kra, resulting in allopatric distribution. Climatic conditions, in particular rainfall, that differ on each side of the Isthmus of Kra may play an important role in limiting the immigration of both clades. For the within-populations of either clades C or D, there was no significant correlation between geographic and genetic distance by the isolation-by-distance test, indicating intraspecific gene flow of each clade. Population expansion occurred in clade C, whereas clade D showed a constant population. Taken together, the P. leucomystax complex in Southeast Asia may be diversified by climatic oscillation, leading to allopatric and/or sympatric speciation.