The meiolaniform Patagoniaemys gasparinae from the Upper Cretaceous La Colonia Formation (Chubut, Argentina), Part 1: Postcranial anatomy and paleoecology

Abstract

Patagoniaemys gasparinae is a non-meiolaniid meiolaniform turtle from the Upper Cretaceous La Colonia Formation in Chubut, Argentina. Aside from Meiolania platyceps, no other almost completely preserved meiolaniform turtle has been described in detail to date. This manuscript describes the postcranial anatomy of Pa. gasparinae based on several specimens, including a nearly complete associated skeleton. This makes Pa. gasparinae the most complete Cretaceous meiolaniform known from Gondwana. This detailed description expands the known postcranial anatomy for Pa. gasparinae, originally described in 2011 based on limited remains. Based on the postcranial anatomy, the manuscript explores the paleoecology of this extinct turtle. Analyses of forelimb proportions suggest that Pa. gasparinae would have been terrestrial or amphibious. The amphibious habitat of Pa. gasparinae is also supported by the proportion of stylopodial elements and the plastral morphology. On the other hand, the terrestrial habitat of Pa. gasparinae is supported by the presence of osteoderms. Furthermore, the finding of specimens of different sizes allows for discussing anatomical changes throughout the ontogeny of Pa. gasparinae.