New materials on turtles of the family Nanhsiungchelyidae from the Cretaceous of Uzbekistan and Mongolia, with a review of the nanhsiungchelyid record in Asia

Abstract

This paper presents a review of all known records of turtles of the family Nanhsiungchelyidae in Asia, including data from 37 localities. Among new materials described herein are remains of nanhsiungchelyids (Hanbogdemys sp. 1 and 2 and Nanhsiungchelyidae indet. 1–10) from 12 Early and Late Cretaceous localities of Mongolia and Uzbekistan. Nanhsiungchelyidae from the Early Cretaceous (Aptian–Albian) of Mongolia are reported for the first time. Reassessment of the published data on Asian nanhsiungchelyids allows us to change taxonomic status of many previous findings from Basilemys sp. or Zangerlia sp. to Nanhsiungchelyidae indet. In addition, we refer Bulganemys jaganchobili to Hanbogdemys. The latter genus thus has the widest temporal distribution (from Cenomanian to Campanian) among nanhsiungchelyids in Asia. Our analysis of the nanhsiungchelyid record in Asia shows that the record is richest in the Cenomanian–Campanian of Mongolia, whereas the Maastrichtian record from Mongolia should be considered questionable. These facts emphasize the particular importance of the Mongolian record of nanhsiungchelyids for understanding the diversification and evolution of this group.