KHUNNUCHELYS GEN-NOV, A NEW TRIONYCHID (TESTUDINES, TRIONYCHIDAE) FROM THE LATE CRETACEOUS OF INNER-MONGOLIA AND UZBEKISTAN

A new trionychid, Khunnuchelys gen.nov., represented by two new specie s, Khunnuchelys erinhotensis sp.nov. and Khunnuchelys kizylkumensis sp .nov. is described. Khunnuchelys erinhotensis is based on a large, wel l-preserved skull from the Iren Dabasu Formation in Inner Mongolia, an d K. kizylkumensis is based on a series of partial skulls and isolated skull elements from the Dzhyrakuduk locality, Bissekty Formation, Uzb ekistan. The occurrence of this trionychid in these two localities rei nforces the suggestion of faunal similarity between the Iren Dabasu an d Bissekty formations. Khunnuchelys is distinctive in the extensive de velopment of the triturating surface, proportions of the skull, and fe atures of the braincase. Conchochelys from the Paleocene of North Amer ica shares with Khunnuchelys derived features of the palate and brainc ase, and the two genera may be members of a monophyletic clade of trio nychids. Autapomorphies of the triturating surface and associated feat ures in Khunnuchelys are interpreted as durophagous specializations.