Phylogeny of the Eurasian freshwater turtles of the genus Mauremys Gray 1869 (Testudines), with special reference to a close affinity of Mauremys japonica with Chinemys reevesii

Phylogenetic relationships of the freshwater turtles of the genus Mauremys and representatives of several other batagurid genera were inferred from variations in 863 base positions of mitochondrial 12S and 16S rRNA genes. Results strongly suggested the non-monophyly of Mauremys by indicating the closest affinity of Mauremys japonica with Chinemys reevesii, the type species of the genus Chinemys. Recent morphological analyses of the batagurid genera suggested that Mauremys is a basal stock of the subfamily Geoemydinae, whereas Chinemys is a member of the subfamily Batagurinae as supported by several putative synapomorphs with other batagurine genera. It is thus probable that the morphological character states used to define Mauremys actually represent symplesiomorphy, and that morphological character states shared between Chinemys and other batagurine genera have resulted from convergence. Also, our results did not support a sister-group relationship between Mauremys annamensis and Mauremys mutica, which has been implicitly or explicitly assumed by a number of previous authors on the basis of morphological data. Instead, M. annamensis was indicated to be closest to Mauremys iversoni, a species assumed to be most divergent among the East Asian Mauremys by previous authors.