Morphological and genetic discordance in two species of Bornean Leptobrachium (Amphibia, Anura, Megophryidae)

Systematics of Calliophis intestinalis with the Resurrection of Calliophis nigrotaeniatus (Elapidae, Serpentes)

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 sumatranus Lidth De Jeude, 1890, Calliophis intestinalis everetti (Boulenger, 1896), and Callophis furcatus var. nigrotaeniatus Peters, 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.

Genetic boundary and gene flow between 2 parapatric subspecies of brown rats

Two parapatric Rattus norvegicus subspecies, R. n. humiliatus (RNH) and R. n. caraco (RNC), are classified according to morphological divergence and are mainly distributed in North and Northeast China. Here, we aimed to explore the population genetic structure, genetic boundary, and gene flow in these rats using 16 microsatellite loci. Structure analysis and principal component analysis revealed 3 ancestral clusters. We found that the intermediate cluster exhibited higher genetic diversity and a lower inbreeding coefficient than the other 2 clusters. The genetic differentiation between the 3 clusters was significant but weak, with a higher F_ST value being observed between the clusters on both sides. The subspecies boundary inferred from microsatellite markers may indicate the existence of an admixture or hybridization area covering Liaoning, Inner Mongolia, and Jilin Provinces, rather than corresponding to the administrative provincial boundaries between Liaoning and Jilin. The RNH and RNC subspecies presented moderate gene exchange and an asymmetric bidirectional gene flow pattern, with higher gene flow from the RNH subspecies to the RNC subspecies, constraining speciation. Such genetic characteristics might be explained by biological processes such as dispersal ability, mate choice, and dynamic lineage boundaries.

Two New Ansonia from Mountains of Borneo (Anura, Bufonidae)

Two lineages of stream toads in the genus Ansonia from Malaysian Borneo have long been suspected to be specifically distinct on the basis of molecular data. We assessed the taxonomic status of these lineages using morphological and additional genetic data. In mtDNA phylogeny, each lineage-one from Bario, Kelabit Highlands of Sarawak, the other from Mt. Mulu of Sarawak and the Crocker Range of Sabah-is separated from other congeners by large genetic distances, comparable with those observed between heterospecific species in the genus. These lineages are also morphologically distinguishable from other species, and are considered to represent valid, independently evolving species. We therefore describe them as A. kelabitensis sp. nov. and A. kanak sp. nov.

Strong genetic subdivision in Leptobrachium hendricksoni (Anura: Megophryidae) in Southeast Asia

Many biodiversity hotspots are located in areas with a complex geological history, like Southeast Asia, where species diversity may still be far underestimated, especially in morphologically conservative groups like amphibians. Recent phylogenetic studies on the frog genusLeptobrachiumfrom Southeast Asia revealed the presence of deeply divergent mitochondrial clades inLeptobrachium hendricksonifrom Malaysia and Sumatra but populations from Thailand have not been studied so far. In this study, we re-evaluate patterns of intraspecific genetic diversity inL. hendricksonibased on the analysis of combined sequences of mitochondrial 12S and 16S genes (1310 base pairs) including for the first time samples from southern Thailand. Thai populations ofL. hendricksoniformed a distinct clade with respect to populations from central and southern Malaysia and Sumatra. High sequence divergence between lineages from Thailand, Malaysia and Sumatra suggests the possible presence of cryptic species inL. hendricksoni. Divergence withinL. hendricksonidates back to the late Miocene, around 6 Mya, when lineages from Thailand, north Malaysia and Sumatra split from a lineage in south Malaysia, at about the same time as rising sea levels isolated the Thai-Malay peninsula. Subsequent splits took place later in the Pliocene, around 4.5 and 2.6 Mya. Our results highlight the role of geological history in promoting population divergence and speciation.