Skeletal anatomy of the early Permian parareptile Delorhynchus with new information provided by neutron tomography

Dylan C T Rowe; Joseph J Bevitt; Robert R Reisz

doi:10.7717/peerj.15935

Skeletal anatomy of the early Permian parareptile Delorhynchus with new information provided by neutron tomography

PeerJ. 2023 Aug 22:11:e15935. doi: 10.7717/peerj.15935. eCollection 2023.

Authors

Dylan C T Rowe^{1

2}, Joseph J Bevitt³, Robert R Reisz^{1

2}

Affiliations

¹ Department of Biology, University of Toronto, Mississauga, Mississauga, Ontario, Canada.
² Dinosaur Evolution Research Center, Jilin University, Changchun, China.
³ Australian Centre for Neutron Scanning, Australian Nuclear Science and Technology Organization, Sydney, New South Wales, Australia.

Abstract

Detailed description of the holotype skeleton of Delorhynchus cifellii, made possible through the use of neutron tomography, has yielded important new information about the cranial and postcranial anatomy of this early Permian acleistorhinid parareptile. Hitherto unknown features of the skull include a sphenethmoid, paired epipterygoids and a complete neurocranium. In addition, the stapes has been exposed in three dimensions for the first time in an early parareptile. Postcranial material found in articulation with the skull in this holotype allows for the first detailed description of vertebrae, ribs, shoulder girdle and humerus of an acleistorhinid parareptile, allowing for a reevaluation of the phylogenetic relationships of this taxon with other acleistorhinids, and more broadly among parareptiles. Results show that Delorhynchus is recovered as the sister taxon of Colobomycter, and 'acleistorhinids' now include Lanthanosuchus.

Keywords: Anatomy; Early amniote; Morphology; Neutron computed tomography; Paleontology; Parareptilia; Phylogenetics.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Head*
Neutrons
Phylogeny
Skull* / diagnostic imaging
Stapes

Grants and funding

This study was made possible by funding from the University of Toronto, Jilin University and a Natural Sciences and Engineering Research Council Discovery Grant (RGPIN-2020-04959) to Robert R. Reisz. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.