Abstract
Pareatidae are a group of mollusc‐eating snakes widely distributed in S outh‐eastern A sia. Due to their dietary specialization, the asymmetric dentition of pareatids has recently become an interesting issue in evolutionary biology. However, phylogenetic relationships and species diversity of pareatids are still poorly studied. A total of three P areas species, P . formosanus ( V an D enburgh 1909), P . compressus ( O shima 1910) and P . komaii ( M aki 1931), have been reported for T aiwan. However, only P . formosanus is currently regarded as a valid species. Using mitochondrial sequence phylogeny, nuclear c‐mos haplotype network, as well as multivariate morphometrics, we re‐evaluated the taxonomic status of P areas from T aiwan, the R yukyus and adjacent regions. These lines of evidence showed congruent results for the coexistence of three P areas species in T aiwan, with prominent genetic and morphological differentiation and differing level of dentition asymmetry. The currently used name P . formosanus should be applied only to the snakes with red iris, comparatively short lower jaw and totally smooth dorsal scales. An examination of the type material indicated that the name P . compressus should be regarded as a junior synonym of P . formosensis sensu stricto . P areas komaii ( O shima 1910) is confirmed as a valid taxon with yellow iris, elongated lower jaw and strongly keeled dorsals. The third clade is characterized by a yellow iris, elongated lower jaw and weakly keeled dorsals. Despite their sympatric occurrence, every examined individual showed consistent grouping from mitochondrial, nuclear and morphological markers, indicating there is no gene flow among these three clades. Here, we describe the third clade as a new specie, P areas atayal sp. nov.