Wednesday, February 6, 2013

Asian Wolf Snakes - A Molecular Revision

Lycodon aulicus, Bannerghatta, India. Photo credit: Saleem Hameed

Asian wolf snakes of the genus Lycodon are one of many poorly understood radiations of advanced snakes in the superfamily Colubroidea. Only three of species (of about 37)  have been previously  represented in higher-level phylogenetic analyses, and nothing is known of the relationships among the species in this unique, moderately diverse, group. The genus occurs widely from central to Southeast Asia, and contains both widespread forms and some that are endemic to small islands. One-third of the diversity is found in the Philippine archipelago. Both morphological similarity and highly variable diagnostic characters have contributed to confusion over species-level diversity. Additionally, the placement of the genus in the subfamily Colubrinae remains uncertain, although previous studies have supported a close relationship with the genus Dinodon (contains another eight species). In a forthcoming paper in Zoological Scripta Siler et al. provide the first estimate of phylogenetic relationships within the genus Lycodon using a new multi-locus data set. They provide statistical tests of monophyly based on biogeographic, morphological and taxonomic hypotheses. With few exceptions, we are able to reject many of these hypotheses, indicating a need for taxonomic revisions and a reconsideration of the group's biogeography. Mapping of color patterns on their preferred phylogenetic tree suggests that banded and blotched types have evolved on multiple occasions in the history of the genus, whereas the solid-color (and possibly speckled) morphotype color patterns evolved only once. Their results suggest that the colubrid genus Dinodon is nested within Lycodon—a clear finding that necessitates the placement of Dinodon within Lycodon.

Citation
Siler, C. D., Oliveros, C. H., Santanen, A., Brown, R. M. (2013). Multilocus phylogeny reveals unexpected diversification patterns in Asian wolf snakes (genus Lycodon). Zoologica Scripta,doi:10.1111/zsc.12007

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