Cranial Anatomy and Palaeoneurology of the Archosaur Riojasuchus tenuisceps from the Los Colorados Formation, La Rioja, Argentina

• Published in: PloS one Vol. 11; no. 2; p. e0148575
• Main Authors: von Baczko, Maria Belen, Desojo, Julia Brenda
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 05.02.2016; Public Library of Science (PLoS)
• Subjects: Anatomy; Animals; Archosauria; Argentina; Biology and Life Sciences; Brain - anatomy & histology; Computed tomography; Cranial Nerves - anatomy & histology; Diapsida; Dinosaurs - anatomy & histology; Earth Sciences; Evolution; Feature recognition; Fossils; Geology; Imaging, Three-Dimensional; Maxilla; Maxilla - anatomy & histology; Medicine and Health Sciences; Morphology; Natural history; Ornithosuchidae; Phylogenetics; Reptilia; Research and Analysis Methods; Skull; Skull - anatomy & histology; Taxa; Tomography, X-Ray Computed; Tooth - anatomy & histology; Triassic; Argentina; Scotland
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0148575

Riojasuchus tenuisceps Bonaparte 1967 is currently known from four specimens, including two complete skulls, collected in the late 1960s from the upper levels of the Los Colorados Formation (Late Triassic), La Rioja, Argentina. Computed tomography (CT) scans of the skulls of the holotype and a referred specimen of Riojasuchus tenuisceps and the repreparation of the latter allows recognition of new features for a detailed analysis of its cranial anatomy and its comparison with a wide variety of other archosauriform taxa. The diagnosis of Riojasuchus tenuisceps is emended and two autapomorphies are identified on the skull: (1) a deep antorbital fossa with its anterior and ventral edges almost coinciding with the same edges of the maxilla itself and (2) a suborbital fenestra equal in size to the palatine-pterygoid fenestra. Also, the first digital 3D reconstruction of the encephalon of Riojasuchus tenuisceps was carried out to study its neuroanatomy, showing a shape and cranial nerve disposition consistent to that of other pseudosuchians.