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BackgroundMicrohylidae is a geographically widespread family of anurans. Although several extensive molecular analyses have attempted to elucidate their subfamilial relationships, and correlate these with Mesozoic and Cenozoic continental drifts, consensus has not been reached. Further, generic level relationships have not been well investigated in some microhylid subfamilies, and therefore subfamilial affiliations of some genera are still unclear. To elucidate the phylogenetic positions of two mysterious Asian genera, Gastrophrynoides and Phrynella, and to better understand the trans-continental distributions of microhylid taxa, we performed molecular phylogenetic and dating analyses using the largest molecular dataset applied to these taxa to date.ResultsSix nuclear and two mitochondrial genes (approx. 8 kbp) were sequenced from 22 microhylid frog species representing eight subfamilies. The maximum likelihood and Bayesian analyses could not fully elucidate the subfamilial relationships, suggesting a rapid radiation of these taxa between 85 and 66 million years ago. In contrast, generic relationships of Asian microhylines were generally well resolved.ConclusionOur results clearly showed that one of two problematic Asian genera, Phrynella, was nested in the clade of the Asian subfamily Microhylinae. By contrast, Gastrophrynoides occupied the most basal position of the Australian-New Guinean subfamily Asterophryinae. The estimated divergence of Gastrophrynoides from other asterophryine was unexpectedly around 48 million years ago. Although a colonization scenario via Antarctica to the Australian-New Guinean landmass has been suggested for Asterophryinae, our finding suggested a novel colonization route via Indo-Eurasia.

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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.

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We describe a microhylid frog from Bali, Indonesia as a new species, Microhyla orientalis sp. nov. It belongs to the M. achatina group and is close to M. mantheyi, M. malang, and M. borneensis. It is distinguished from its congeners by a combination of the following characters: small size (adult males about 16-17 mm in SVL); a faint vertebral stripe present; a black lateral stripe from behind eye to half length of trunk; snout rounded in profile; eyelid without supraciliary spines; first finger less than one-fifth of third; tips of three outer fingers weakly dilated, forming weak disks, dorsally with median longitudinal groove; outer palmar tubercle single; tibiotarsal articulation reaching up to center of eye; tips of toes distinctly dilated into disks, dorsally with median longitudinal groove; inner and outer metatarsal tubercles present; four or more phalanges on inner and outer sides of fourth toe, and three phalanges on inner side of fifth toe free of web; and tail of larva with a black marking at middle. The male advertisement call of the new species consists of a series of notes each lasts for 0.01−0.08 s and composed of 3−5 pulses with a dominant frequency of 3.2-3.6 kHz. Uncorrected sequence divergences between M. orientalis and all homologous 16S rRNA sequences available were >6.6%. At present, the new species is known from rice fields between 435-815 m elevation in Wongaya Gede and Batukaru.

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Micryletta inornata (Boulenger 1890), the type species of the genus Micryletta, was originally described from the island of Sumatra in Indonesia. Subsequently, this species has been widely reported from Sundaland (Sumatra and Malay Peninsula), Indo-China, Northeast India and South Andaman, up to southern China and Taiwan. However, since the original description there has been no further report of this species from the type locality or the island. During a herpetofaunal survey in Sumatra, several specimens that are morphologically concordant with the original description and the syntypes of M. inornata were found, and thus the species was rediscovered after 125 years. Here, we provide a redescription of the species based on the freshly collected specimens, along with a detailed morphological and molecular comparison with known congeners. Further, using molecular data from the mitochondrial 16S rRNA gene, our study recovered the Sumatran M. inornata as a phylogenetically distinct lineage from all other populations previously referred to this species. This confirms that all known Micryletta ‘inornata’ populations from regions outside Sumatra constitute several other lineages representing either new species or previously available names currently considered as synonyms, consequently requiring taxonomic validation in the future.