The Anatomical Record, Journal Year: 2024, Volume and Issue: 308(2), P. 369 - 393

Published: June 29, 2024

Abstract Riojasuchus tenuisceps was a pseudosuchian archosaur from the Late Triassic period in Argentina. Like other ornithosuchids, it had unusual morphology such as unique “crocodile‐reversed” ankle joint, lesser trochanter dinosaurs and few archosaurs, robust vertebrae, somewhat shortened, gracile forelimbs. Such traits have fuelled controversies about its locomotor function—were limbs erect or “semi‐erect”? Was quadrupedal bipedal, mixture thereof? These seem to persist because analyses been qualitative (functional morphology) correlative (morphometrics) rather than explicitly, quantitatively testing mechanistic hypotheses function. Here, we develop 3D whole‐body model of R. with musculoskeletal apparatus hindlimbs represented detail using new muscle reconstruction. We use this quantify body dimensions hindlimb leverages enigmatic taxon, estimate joint ranges motion functions. Our supports prior arguments that used an posture, parasagittal gait plantigrade pes. However, some our inferences illuminate contradictory nature evidence system —different features support (or are ambiguous regarding) quadrupedalism bipedalism. Deeper biomechanical could move toward consensus regarding ornithosuchid locomotion. Answering these questions would not only help understand palaeobiology bizarre clade, but also more broadly if how) abilities played role survival versus extinction various lineages during end‐Triassic mass event.

Language: Английский