THE TYPE SERIES OF 'SINEMYS'WUERHOENSIS, A PROBLEMATIC TURTLE FROM THE LOWER CRETACEOUS OF CHINA, INCLUDES AT LEAST THREE TAXA

Abstract:  We re-examine the type series of ' Sinemys ' wuerhoensis Yeh (at least 20 specimens, including several shells and skulls on three slabs of matrix and one isolated skull) from the Early Cretaceous Tugulu Group of China. Our study shows that the type series of ' S. ' wuerhoensis is actually a chimera made up of at least three distinct taxa. The holotype of this taxon should be assigned to the basal eucryptodire genus Xinjiangchelys Yeh. As there are no characters that distinguish ' S. ' wuerhoensis from Xinjiangchelys species, we consider it to be a nomen dubium . This new assignment of ' S. ' wuerhoensis expands the temporal range of Xinjiangchelys from the Late Jurassic into the Early Cretaceous in Asia. The majority of the paratypes of ' S. ' wuerhoensis (several shells in dorsal and ventral aspect and skulls) are referred to the basal eucryptodire genus Ordosemys Brinkman and Peng. We establish a new name for these specimens, Ordosemys brinkmania sp. nov. One additional specimen in the type series of ' S. ' wuerhoensis , a skull, is referred to cf. Pantrionychia Joyce, Parham and Gauthier indet.