Genome-based phylogeography of the red bamboo ratsnake Oreocryptophis porphyraceus (Serpentes: Colubridae)

Speciation is often considered as a prolonged, continuous and complex process shaped by interactions among multiple evolutionary forces, including both biotic and abiotic factors. Robust species delimitation is fundamental for understanding the basic biology and ecology of organisms and of course the implementation of effective conservation policies. The red bamboo ratsnake (Oreocryptophis porphyraceus) is a polytypic species in the family Colubridae widely distributed across Asia with a subspecific taxonomy has long been complex and controversial. Here, we integrated double-digest restriction-site associated DNA sequencing (ddRAD-Seq) with mitochondrial DNA (mtDNA) data to re-evaluate the subspecific taxonomy of this species primarily using samples from China and Vietnam. Phylogenetic relationships, population structure, tests of gene flow and species delimitation analyses consistently revealed that the species comprises at least four highly divergent, geographically structured lineages (five in the mtDNA phylogeny). Notably, these distinct evolutionary lineages are inconsistent with current taxonomic classifications. We propose a revised taxonomy that integrates genomic evidence with morphological data, and we discuss the distribution boundaries for each delineated species.