New information on the anatomy and histology of Gracilisuchus stipanicicorum (Archosauria: Pseudosuchia) from the Chañares Formation (early Carnian), Argentina
LECUONA, A.; DESOJO, J.B.; CERDA, I.A.
COMPTES RENDUS PALEVOL
ELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER
Lugar: Paris; Año: 2020 vol. 19 p. 40 - 62
Gracilisuchus stipanicicorum is a basal suchian from the Late Triassic ChañaresFormation (Argentina), nested in the recently erected Gracilisuchidae, alongwith Turfanosuchus dabanensis and Yonghesuchus sangbiensis from China. Thesix known specimens of Gracilisuchuspreserve most of the skeleton, lacking only most of the shoulder girdle andforelimb. Our latest fieldwork has recovered two specimens that preserve previouslyunknown elements, including the humerus, radius, and ulna, as well as the femur,presacral vertebrae, and paramedian osteoderms. The femur and osteoderms were histologicallysectioned, which has never been done for Gracilisuchidae. The anatomicalanalysis revealed characters in the new elements that improve our understandingof the anatomy of Gracilisuchus. Bonehistology revealed that the specimen CRILAR PV 490 died before reaching somaticmaturity and that growth was relatively slow compared to other pseudosuchians. Thisstudy increases the knowledge of the anatomy of Gracilisuchus and represents a new step towards a broader understandingof Gracilisuchidae and basal suchian clades.