Assessing the palaeobiology of Vespersaurus paranaensis (Theropoda, Noasauridae), Cretaceous, Bauru Basin – Brazil, using Finite Element Analysis

Abstract

Noasauridae is a group of theropod dinosaurs mostly present in Gondwanan deposits of Jurassic and Cretaceous age. Vespersaurus paranaensis from the Bauru Basin (Caiuá Group, Cretaceous) was the first Brazilian taxon assigned to the clade. This work applied Finite Element Analysis (FEA) to investigate the functional morphology of some skeletal elements assigned to Ves. paranaensis (one tooth and two pedal ungual phalanges). The tooth was modeled and tested in six different scenarios to infer the performance of its crown in different putative feeding conditions. Three different extrinsic scenarios were tested on the ungual phalanges to simulate potential habits in which these structures were involved (piercing, scratch-digging, and hook-and-pull). The scenarios tested on the tooth suggest an ideal bite angle of 45°, with higher von Mises stress/element in the other angles. This indicates that the dentition of this noasaurid was not adapted for struggling prey, nor for harder food items. The FEA results of the ungual phalanges of Ves. paranaensis suggest a similar performance in the three tested scenarios, therefore not specifically adapted for any of those specific functions. Additionally, these phalanges are similar in shape to those of living mammals with scansorial, fossorial, and terrestrial habits. Collectively, this information suggests that, Ves. paranaensis had a generalist diet, seeking to hunt small vertebrates, invertebrates, or immobile prey, such as carcass, and did not feed on larger animals.