Wednesday, June 29, 2011

[Herpetology • 2008] Ghatixalus • new endemic Genus from the Western Ghats of India

Abstract: Since its original description, the Indian treefrog species Polypedates variabilis Jerdon, 1853 has been assigned variously to one of the widespread genera Polypedates Tschudi, 1832, Rhacophorus Kuhl & van Hasselt, 1822, and Philautus (Kirtixalus) Dubois, 1987. Here we present phylogenetic analyses based on 1.4 kb of mitochondrial DNA showing that P. variabilis and a previously undescribed relative are not nested within any of those genera, but stem from a lineage that originated relatively early in the rhacophorid radiation. We propose the name Ghatixalus gen. n. for this lineage, whose known members are restricted to high altitudes in the Western Ghats of India. The sister species of G. variabilis (Jerdon), comb. n. is described as Ghatixalus asterops sp. n. The morphological and ecological features of both species are discussed.

Keywords: Biodiversity; India; Molecular phylogenetics; New genus; New species; Old world treefrogs

Fig. 2. Ghatixalus gen. n. (A–C) G. variabilis: (A) brown colour variation, (B) green colour variation, (C) close-up of eye showing unicoloured golden iris. (D and E) G. asterops sp. n.: (D) brown colouration of adult frogs, (E) close-up of eye showing golden starlike pattern in iris.

Fig. 3. Ghatixalus gen. n. (A–D) G. variabilis: (A) dorsal view, (B) lateral view of head, (C) ventral view of left hand. (D) ventral view of left foot. (E–H) G. asterops sp. n.: (E) dorsal view, (F) lateral view of head, (G) ventral view of left hand, (H) ventral view of left foot. Scale bars ¼ 10 mm

Ghatixalus asterops Biju, Roelants & Bossuyt, 2008

Fig. 1. Phylogenetic relationships among rhacophorid genera, as supported by the maximum-likelihood tree. Type species names labelled ‘‘(T)’’. Branches in bold highlight phylogenetic position of Ghatixalus gen. n., proposed here for Polypedates variabilis Jerdon and a newly discovered species. Numbers above and below branches represent non-parametric bootstrap values under MP, and Bayesian posterior probabilities, respectively.

Fig. 4. Distribution map for Ghatixalus gen. n., showing disjunct distribution of its two known species, G. variabilis (circles) and G. asterops sp. n. (triangles).

Biju, Roelants & Bossuyt, 2008. Phylogenetic position of the montane treefrog Polypedates variabilis Jerdon, 1853 (Anura: Rhacophoridae), and description of a related species. Organisms Diversity & Evolution. 8:4, 267-276: