BIOMECHANICAL SKULL ANALYSIS OF AN AETOSAUR NEOAETOSAUROIDES ENGAEUS USING FINITE ELEMENT ANALYSIS

Abstract

Aetosaurs are an archosaur group with a worldwide distribution during the Late Triassic. They were quadrupedal amniotes, had small heads relative to their body size, and had a long tail. Characterized by a dorsal and ventral carapace formed by ornamented and articulated osteoderms, aetosaur feeding ecology is poorly understood. Although aetosaurs are historically considered as the only herbivore among early pseudosuchian archosaurs, some authors have proposed omnivorous and/or scavengers habits for this group. Neoaetosauroides engaeus Bonaparte, 1969, an aetosaur from Late Triassic known from three relatively well preserved skulls (from the Los Colorados Formation, La Rioja, Argentina), is an excellent taxon to make biomechanics models of feeding to decipher the feeding ecology of this clade. We applied the Finite Element Method (FEM) for estimating the bite force and evaluated the structural response of the skull at different positions during the food processing. Our results show that the skull of N. engaeus generated a bite force of 3.6kN (magnitude comparable with the measurement made in Alligator mississippiensis) and could resist lateral and longitudinal forces during feeding. This indicates that these animals were capable of hunting of small living prey with their jaws (e.g. cynodonts), and/or drag carcasses of larger sizes (e.g. dicynodont). These results support possible zoophagy or omnivory for N. engaeus, and thus expanding the potential ecological roles of aetosaurs.