Discovery of an old, archipelago-wide, endemic radiation of Philippine snakes.

The extraordinarily rich land vertebrate biodiversity of the Philippines includes at least 112 species of terrestrial snakes (74% of which are endemic to the archipelago) in 41 genera (12% endemic). Endemic Philippine snake genera include Cyclocorus (two species), Hemibungarus (three species), Hologerrhum (two species), Oxyrhabdium (two species), and Myersophis (monotypic). Although Hemibungarus and Oxyrhabdium have been included in previous species-level phylogenies, the affinities of the other three Philippine endemic genera are completely unknown. We generated novel DNA sequences for six species from four genera and analyzed these in conjunction with data from earlier studies to infer a phylogeny for the group containing Colubridae, Elapoidea (Elapidae + Lamprophiidae), and Homalopsidae. We present a novel phylogenetic result that strongly supports the existence of an entirely endemic Philippine radiation of elapoid snakes that originated 35-25 million years ago. We provide a revised, phylogeny-based classification to accommodate the new clade, transfer Cyclocorus, Hologerrhum, and Myersophis to Lamprophiidae, and provide the first estimate of the evolutionary relationships among these genera and the related Oxyrhabdium, setting the stage for future investigation of this entirely endemic, novel Philippine elapoid radiation.