Fossil Record 23(1): 83-93, doi: 10.5194/fr-23-83-2020
An alternative interpretation of Peltochelys duchastelii as a paracryptodire
expand article infoWalter Joyce, Yann Rollot
‡ Departement für Geowissenschaften, Universität Freiburg, Freiburg, 1700, Switzerland
Open Access

Peltochelys duchastelii is an enigmatic turtle from Early Cretaceous (middleBarremian–early Aptian) Sainte-Barbe Formation of Bernissart, Belgium. In more recent literature, there has been strong support for thetrionychian affinities of this taxon, but this interpretation is lessconsistent with external data, in particular biogeography and temporalconsiderations. We provide a reinterpretation here of the lectotype ofPeltochelys duchastelii that differs from more recent ones in key features. Although we agree thatthis turtle lacks mesoplastra, we conclude that it has 11 pairs ofperipherals (not 10), likely had 12 pairs of marginals (not 11),lacks a contact between peripheral 1 and costal 1, and that a midlinecontact of peripherals 1 hinders the nuchal from contributing to the marginof the shell. This unusual set of characters is otherwise known from roughlycoeval taxa from Europe and North America. Phylogenetic analysis yields apreviously unrecognized clade of basal paracryptodiran turtles from the LateJurassic to Paleogene of Euramerica united by a nuchal that is withdrawnfrom the anterior margin of the shell. The name Compsemydidae is referred to this clade. The novel hypothesis suggests that Peltochelys duchastelii did not immigrate from Asiabut instead originated in Europe.