Nishikawa, K. (2012). Phylogenetic and taxonomic relationships of the Polypedates leucomystax complex (Amphibia). -Zoologica Scripta, 42, 54-70. We investigated the phylogenetic and taxonomic relationships and estimated the history of species diversification and biogeography in the Asian rhacophorid genus Polypedates, focusing on the Polypedates leucomystax complex, whose members are notoriously difficult to classify. We first estimated phylogenetic relationships within the complex using 2005-bp sequences of the mitochondrial 12S rRNA, tRNA val and 16S rRNA genes with maximum parsimony, maximum likelihood (ML) and Bayesian methods of inference. Polypedates exhibits well-supported monophyly, with distinct clades for P. otilophus, P. colletti, P. maculatus and the P. leucomystax complex, consisting of P. macrotis, and the Malay (Polypedates sp. from Malay Peninsula), North China (P. braueri), South China (Polypedates cf. mutus 1), Indochina (P. megacephalus), Sunda (P. leucomystax) and Laos (Polypedates cf. mutus 2) clades. In a subsequent phylogenetic analysis of 4696-bp sequences of the nuclear brain-derived neurotrophic factor (BDNF), sodium ⁄ calcium exchanger 1 (NCX), POMC, Rag-1, Rhod and Tyr genes using Bayesian methods of inference, all of these clades were recovered. Some clades of the P. leucomystax complex occur sympatrically and show high genetic diversity or morphological and acoustic differences. Similar tendencies were observed between some allopatric clades. Therefore, we consider each of these groups to be distinct specifically. We also estimated absolute divergence times within the genus using Bayesian methods. Divergence in Polypedates began with the divergence of a primarily South Asian Clade from the common ancestor of secondarily South-East Asia P. maculatus and South-East Asian members. The divergence between the latter occurred much later. The P. leucomystax complex diverged in the Pliocene, much later than other congeners, and seems to have been greatly affected by human-related dispersal after the Pleistocene.

A fanged frog Limnonectes kuhlii was once thought to be wide-ranging in Southeast Asia, but is now confined to its type locality Java through recent phylogenetic studies, which clarified heterospecific status of non-Javanese populations, and monophyly of Bornean populations. However, large genetic differences among Bornean populations suggest occurrence of cryptic species, which we test using dense geographic sampling. We estimated the phylogenetic relationships among samples of Bornean populations together with their putative relatives from the continental Southeast Asia, using 2517bp sequences of the 12S rRNA, tRNA(val), and 16S rRNA of mitochondrial DNA, and 2367bp sequences of the NCX1, POMC, and RAG1 of nuclear genes. In the mtDNA trees, Bornean L. kuhlii-like frogs formed a monophyletic group split into 18 species lineages including L. hikidai, with the deepest phylogenetic split separating L. cintalubang from the remaining species. Almost all of these lineages co-occur geographically, and two to three lineages were found syntopically in each locality. Co-occurrence of more than one lineage may be maintained by differential morphology and microhabitat selection. These syntopic lineages should be regarded as distinct species. Our results clearly indicate that taxonomic revision is urgent to clarify many evolutionary problems of Bornean L. kuhlii-like frogs.

No abstract

Systematic relationships of fanged frogs usually associated with Limnonectes kuhlii are assessed using 15 samples from Japan, Chinese Mainland and Taiwan, Vietnam, Laos, Thailand, Malaysia (Borneo), and Indonesia. Phylogenetic relationship inferred from the mitochondrial 12S rRNA, tRNA val , and 16S rRNA gene sequences revealed that fanged frogs sampled are not monophyletic with the topotypic L. kuhlii from Java. Samples from Yunnan of southern China (L. bannaensis), northern Laos and central Vietnam, and those from Jiangxi of eastern China (L. fujianensis), Taiwan and Japan (L. namiyei), respectively, form monophyletic groups, and are collectively sister to the Thai sample (L. megastomias). All these samples, L. fragilis from Hainan of southern China, and a group of Bornean samples show unresolved relationships with Javanese L. kuhlii. From the resultant phylogeny and genetic distances found among samples, L. "kuhlii" from Taiwan and L. fujianensis, and L. "kuhlii" from northern Laos and central Vietnam and L. bannaensis, respectively, are surmised to be conspecific. These fanged frogs are morphologically similar to, but phylogenetically distant from, L. kuhlii sensu stricto. Limnonectes namiyei, L. fujianensis, and L. bannaensis are considered to have a common ancestor whose chromosome number was 2n=22, unlike L. fragilis, L. kuhlii and many other frogs with 2n=26 chromosomes.

Phylogenetic relationships inferred from sequences of the mitochondrial 12S rRNA, tRNA val , and 16S rRNA genes and nuclear POMC and RAG-1 genes revealed that fanged frogs from Thailand usually associated with Limnonectes kuhlii are monophyletic and are collectively sister to the clade containing three Chinese and Japanese species. Within the Thai clade, the northern lineage, the southern lineage, and a population originally assigned to L. megastomias show unresolved relationships with each other, but are separated by genetic distances that correspond to values found among species of the Chinese-Japanese clade. Hybridization and past gene introgression are not detected among these three lineages of fanged frogs from Thailand. Adult specimens of the northern and southern lineages are phenotypically similar to each other, but can be separated by the combination of several morphometric characters. From the genetic and morphological evidence, they are considered to represent taxonomically different species. We therefore describe the northern lineage as L. taylori sp. nov. and the southern lineage as L. jarujini sp. nov. Taxonomic identity of the Loei population of L. megastomias requires future morphological investigation. The distribution pattern of fanged frogs within Thailand is discussed and the significance of the Three Pagodas Fault Zone is noted.