BITE FORCE OF THE BAURUSUCHIDAE (CROCODYLIFORMES, NOTOSUCHIA) USING FINITE ELEMENT ANALYSIS

Members of Baurusuchidae are typically found among the crocodyliform-dominated communities from the Bauru Group (Late Cretaceous, Brazil). The anatomical traits observed in baurusuchids (e.g. ziphodonty), and direct evidence (i.e. fossilized gut contents), points to a terrestrial predatory habit for the group. Yet, the assumed palaeobiology of baurusuchids is primarily derived from broad generalizations, whereas quantitative analyses are lacking. Our goal was to determine the bite force of one baurusuchid specimen using finite element analysis (FEA). The specimen used is an almost complete skeleton from the Adamantina Formation (skull length = 33 cm; estimated body length = 200 cm). The skull and lower jaws were CT scanned and a series of digital tools were applied to transform the CT data into a tetrahedral mesh, simulate forces, and finally solve the model with FEA. The muscles of the adductor chamber of the baurusuchid were reconstructed based on the osteological correlates mapped in extant crocodylians. Likewise, the forces generated by each muscle, the direction of the force vectors applied in the digital models, and the properties of bones and teeth were based on extant crocodylians. The bite force estimated for this specimen was approximately 600 N, which is lower than empirical data from extant crocodylians of comparable sizes. The baurusuchid bite force is also only a fraction of the bite forces calculated for adult theropod dinosaurs, which could potentially exceed 50,000 N. The association of a weak bite force and predatory habit is uncommon among tetrapods. However, this combination is observed in Komodo dragons, which were measured as having a maximum bite force of approximately 150 N. Komodo Dragons increase prey injuries and maximize prey take down by other means, such as the ziphodonty and biting and pulling behaviour. Our results suggest that baurusuchids and coeval theropods did not rely on the same strategies for taking down prey, and, if they hunted similar prey, baurusuchids most likely relied on additional mechanisms to maximize prey injury. [Rutherford Fund Strategic Partner Grants]