New insights into the cranial osteology of the Early Cretaceous paracryptodiran turtle Lakotemys australodakotensis

PeerJ. 2022 Apr 12:10:e13230. doi: 10.7717/peerj.13230. eCollection 2022.

Abstract

Lakotemys australodakotensis is an Early Cretaceous paracryptodire known from two shells and a skull from the Lakota Formation of South Dakota, USA. Along with the Early Cretaceous Arundelemys dardeni and the poorly known Trinitichelys hiatti, Lakotemys australodakotensis is generally retrieved as an early branching baenid, but more insights into the cranial anatomy of these taxa is needed to obtain a better understanding of paracryptodiran diversity and evolution. Here, we describe the skull of Lakotemys australodakotensis using micro-computed tomography to provide the anatomical basis for future phylogenetic analyses that will be needed to investigate more precisely the intrarelationships of Paracryptodira. Preliminary comparisons reveal that the cranial anatomy of Lakotemys australodakotensis is very similar to that of the Aptian-Albian basal baenid Arundelemys dardeni, that both taxa exhibit a remarkable combination of derived characters found in baenodds and characters found in non-baenid paracryptodires, particularly Pleurosternidae, and that Lakotemys australodakotensis is the only known baenid to date to possess a canal for the palatine artery.

Keywords: Anatomy; Baenidae; Paracryptodira; Systematics; Testudinata; Turtles.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Osteology
  • Phylogeny
  • Skull / diagnostic imaging
  • Turtles* / anatomy & histology
  • X-Ray Microtomography

Grants and funding

Yann Rollot, Serjoscha W. Evers, and Walter G. Joyce were supported by the Swiss National Science Foundation (SNF 200021_178780/1). Richard L. Cifelli was supported by the American Chemical Society Petroleum Research Fund (ACS–PRF#38572–AC8) and the U.S. National Science Foundation (FRES–1925896). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.