A New, Miniaturized Genus and Species of Snake (Cyclocoridae) from the Philippines

The Philippine archipelago is an exceptionally biodiverse region that includes at least 112 species of land snakes from 41 genera and 12 families. Recently, Cyclocoridae (formerly Lamprophiidae: Cyclocorinae) was proposed as a distinct, Philippine-endemic family, containing four genera: Cyclocorus, Hologerrhum, Myersophis, and Oxyrhabdium. Here, we describe an additional cyclocorid genus and species, Levitonius mirus, new genus and species, from Samar and Leyte Islands, Philippines. Molecular data support Levitonius, new genus, to be most closely related to Myersophis and Oxyrhabdium, and it shares multiple skeletal characteristics with these genera; Levitonius, new genus, differs from all of these taxa in body size, scalation, and other characters. Skeletal and other phenotypic data suggest that Levitonius, new genus, is fossorial and likely has a diet that is specialized on earthworms. Levitonius mirus, new genus and species, has a maximum total length of 172 mm and is at present the smallest known species in Elapoidea. Our results highlight the need for future work on Samar and Leyte Islands, which have received relatively little attention from systematists, in part because of a prevailing biogeographic paradigm that predicted (not necessarily correctly) that these islands would simply have a nested faunal subset of the Mindanao faunal region land vertebrates. The discovery of a strikingly distinct and phylogenetically divergent snake lineage on these landmasses joins numerous related studies calling for a wholesale reconsideration of the Pleistocene Aggregate Island Complex model (the PAIC paradigm of diversification) biogeographic framework.