Objective
Numerous vertebrate fossils,dominated by the Mammuthus-Coelodonta fauna,have been found from many Late Pleistocene fossil sites in Heilongjiang,northeast China(Jin and Kawamura,1996).However,fossil turtles have not yet been reported.Recently,two soft-shelled turtle(trionychid)costal plates have been discovered together with other typical Mammuthus-Coelodonta fauna fossils.
Soft-shelled turtle fossil remains are scarce in northeast China.To date,only three taxa(Khunnuchelys erinhotenisis,Perochelys lamadongensis,"Trionyx"jixiensis)have been reported from Cretaceous deposits(Li and Tong,2017).Cenozoic soft-shelled turtle fossils are extremely rare and have not received any formal description.The specimens we describe in this study fill a noticeable gap in the soft-shelled turtle fossil record of the Cenozoic of northeast China,which provides new fossil data for studying the diversity and stratigraphic distribution of the group.