Phylogenetic Relationships of the Scincella modesta Group (Squamata: Scincidae) in East Asia

The taxonomy of East Asian Scincella has been confused. Although the taxonomic status of some East Asian species was once synonymized Chinese S. modesta by Ouboter, this revision is no longer supported on the basis of morphological characteristics. However, molecular studies have not been conducted well, and the phylogenetic relationships of these East Asian species are not well understood. In this study, we tentatively labeled the nine species once synonymized with S. modesta as the “S. modesta group,” and used nuclear and mitochondrial DNA data from six of these species to reconstruct phylogenetic relationships. Within the S. modesta group, each species showed distinct lineages and four subclades were recognized in our study: (I) S. vandenburghi in Korea to Tsushima Island, Japan and S. modesta from central China, near the Changjiang River; (II) Scincella species of southern Ryukyus and Taiwan, S. boettgeri, and S. formosensis, etc.; (III) S. modesta from Ningbo (= Ningpo), Zhejiang, and Hong Kong; and (IV) Southwest Chinese Scincella, S. potanini, S. monticola, etc. This phylogenetic analysis revealed that S. modesta contained two distinct lineages at the species level. The estimated divergence dates imply that speciation of the S. modesta group began around the Early Miocene, with subclade IV diverging first, followed by III, and I and II diverged around the Late Miocene. Then, it is considered that this group diversified during the Pliocene. In addition, we propose a taxonomic suggestion for subspecies of S. modesta.