Taxonomic status of the legless lizard Ophisaurus (Squamata: Anguidae) in Taiwan: Molecular data, morphology, and literature review

The legless lizard genus Ophisaurus is in the family Anguidae. Two species are currently recognized in Taiwan: O. harti with blue dorsal markings, and O. formosensis with uniform dorsal coloration. However, due to the secretive life history and extremely few records, the taxonomic status of O. formosensis remains problematic. In order to resolve this controversy, molecular and morphology data were obtained from 14 Ophisaurus individuals with blue dorsal markings (O. harti) and 5 without markings (O. formosensis). Complete 12S rRNA and partial cytochrome b sequences revealed no genetic differentiation between these 2 color morphs, in addition, some of their haplotypes ace shared. We reviewed the related literature and evaluated 8 different morphological characters that were once mentioned or still apply for species recognition, but none of them provided a diagnostic distinction between these 2 color morphs in our samples. Furthermore, some characters of O. formosensis proposed by recent herpetologists are incongruent with the description of the holotype in the original paper. Based on their sympatric distribution, we conclude that there is only 1 Ophisaurus species in Taiwan, and O. formosensis should be a synonym of O. harti.