Revision of the poorly known Dorsetochelys typocardium, a relatively abundant pleurosternid turtle (Paracryptodira) in the Early Cretaceous of Europe

Abstract

Pleurosternidae is one of two clades of freshwater turtles recorded both in the European Late Jurassic and Early Cretaceous records. Pleurosternon bullockii is the only well-known Early Cretaceous representative of this clade. “Pleurosternon” typocardium, from England, was defined in the 19th century. However, available information on it is very limited as it has never been thoroughly revised. In fact, all attributions of elements to its plastron have already been considered doubtful. In addition, many carapace regions were poorly understood and some characters have been wrongly interpreted in several papers. More than ten specimens are here attributed to this taxon, until now only known by the shell. Many of these specimens have never been described or figured. Therefore, its shell is characterized in detail herein. This analysis paves the way to refuting the validity of several taxa, supporting the recently proposed new combination of Dorsetochelys typocardium. This study also extends the palaeobiogeographic range of distribution of this species, so far recognized only from records from England. As a result, the known post-Jurassic record of Pleurosternidae is identified as exclusively composed of two taxa: Pleurosternon bullockii and Dorsetochelys typocardium.