A plastron fragment reveals a previously unrecorded turtle species in the Eocene of Messel Pit, Germany

Abstract

Depending on taxonomic opinion, between four and five turtle species are well attested for the Middle Eocene Messel Pit formation of Germany. Here, we describe specimen SMF ME-3495 from the Messel collection of the Senckenberg Museum in Frankfurt, which unambiguously corresponds to an additional turtle species. The specimen consists of a partial anterior plastral lobe that can be distinguished from other Messel turtle taxa on the basis of the presence of gular tubercles, an extensive epiplastral lip, narrow gulars that lap onto the entoplastron, and a sinuous gulo-humeral sulcus. The fragment is not sufficient to diagnose another contemporary European turtle taxon, but its epiplastral lip morphology is reminiscent of “ptychogasterid” geoemydids (Cryptodira). We also remark on bone corrosion consistent with “shell disease” and distinctive coloration.