The taxonomic status of two populations of stream toads of the genus Ansonia from Thailand, previously suspected to be specifically distinct on the basis of molecular data, are assessed using morphological and additional genetic data. In mtDNA phylogeny, each of the two Thai lineages, one from Pilok Subdistrict, Kanchanaburi, and another from Phuket Island, are separated from other congenerics from the Thai-Malay Peninsula by large genetic distances, comparable with those observed between other species in the genus. Although each of the two lineages is superficially similar to other species morphologically, they are distinguishable in several morphological traits and are considered to represent valid, independently evolving species. We therefore describe them as A. pilokensis sp. nov. and A. phuketensis sp. nov.
Keywords: Ansonia phuketensis; Ansonia pilokensis; Thailand; biogeography; mtDNA phylogeny.