New insights into the anatomy and systematic of 'Papoulemys' laurenti, a representative of Neochelys (Chelonii, Podocnemididae) from the early Eocene of the south of France

摘要

Neochelys is a European Eocene genus of turtles well represented by various species. It is one of the few members of Pleurodira identified during the Cenozoic of this continent. However, it has generally been recognized only by shells, and too few skulls are known to provide useful data for comparative diagnosis and relationships. The European Eocene 'Papoulemys' had been proposed as a junior synonym of Neochelys, the species 'P.' laurenti becoming N. laurenti, but this hypothesis was insufficiently justified. A second skull of this species, from its type locality (the French locality of Saint-Papoul), is analysed here together with several unpublished skulls of other Neochelys spp. from various countries and ages, providing new arguments to refute the validity of the characters used to diagnose 'Papoulemys' as a genus distinct from Neochelys. They are exclusively cranial characters since only its holotype (a skull) was known. Several shells from the type locality, on which the reattribution to N. laurenti had been proposed (but only synthetically), are also studied in detail here, as well as other unpublished Neochelys spp. shells. We propose a new diagnosis for ` Papoulemys' laurenti, reallocating the species to Neochelys. We also expand the available information on this genus and on several of its representatives.