Biomechanical analysis of the cranio-mandibular complex of Araripesuchus gomesii (Notosuchia, Uruguaysuchidae)

FEDERICO JAVIER DEGRANGE; CASEY M. HOLLIDAY; KALEB C. SELLERS; MAURO NICOLAS NIETO; DIEGO POL

Virtual

Congreso; 1ra. Reunión Virtual de Comunicaciones de la Asociación Paleontológica Argentina (RVCAPA); 2020

Notosuchia is a clade of crocodyliforms highly successful and diverse in the Cretaceous of Gondwana. Araripesuchus gomesii is a small early notosuchian from the Lower Cretaceous of Brazil in which a finite element analysis (FEA) was performed in this study. The skull and jaw of A. gomesii was reconstructed from CT scans. The FE analysis was performed using published bone properties for crocodiles (Young´s modulus: 8,8 GPa; Poisson ratio: 0,4; Bone density: 1,0x10-6 kg/mm3). The adductor musculature and their respective attachment areas were reconstructed based on Extant Phylogenetic Bracket (EPB). Different functional scenarios were tested applying an estimated 158 N bite force: unilateral bite, bilateral bite, pullback, head-shake and head-twist. In the different simulations, the cranio-mandibular complex of Araripesuchus suffers more stress in the head-shake movement, followed by the several unilateral bites where the most affected regions were the quadrate, the ventral region of the infratemporal bar and preorbital region (anterior jugal, posterior maxillae, lacrimals, nasal, prefrontals and anterior frontal). On the other hand, the head-twist and the pullback movements are the one with the less stress values. Araripesuchus is considered at least omnivorous and due to its small size and relatively weak bite force, it probably fed on small prey that it could catch with the entirety of its mouth, such as insects and small invertebrates, corpses that it fortunately found and possibly fruits and seeds. It is possible that for the attack on larger prey it generated various movements of its body as observed in other extant tetrapods.