The description and phylogenetic position of a new nanhsiungchelyid turtle from the Late Cretaceous of Mongolia

Abstract

This paper describes a new nanhsiungchelyid turtle, Kharakhutulia kalandadzei gen. et sp. nov., based on two partial shells and additional shell fragments from the lower part of the Bainshire Formation (Upper Cretaceous, Cenomanian-lower Turonian) of the Khara Khutul locality of Eastern Mongolia. Our phylogenetic analysis places Kharakhutulia kalandadzei as the most basal member of the Nanhsiungchelyidae and suggests new relationships within this group. Previously reported nanhsiungchelyid specimens from the Khara Khutul are reassigned to Nanhsiungchelyidae indet. and Hanbogdemys sp. indet. Thus the Khara Khutul includes at least two valid taxa of nanhsiungchelyids. Our analysis of the nanhsiungchelyid record in Asia shows that other localities have only a single representative of this clade, making Khara Khutul a unique site. The basal phylogenetic position of Kharakhutulia kalandadzei emphasizes the importance of the study of this and other Cenomanian-Turonian localities of Asia to better understand the basal diversification of the Nanhsiungchelyidae.