A unique predator in a unique environment
By the end of the age of dinosaurs, the southwestern region of Brazil was dominated by a distinct kind of archosaur. Baurusuchids, a group of Late Cretaceous (90-65 million years) crocodyliforms were the apex predators in those ecosystems where dinosaur remains are scarce. They didn't resemble much extant crocodyles; with a more erect position, baurusuchids had a disproportionate large and high skull, with a short tooth roll bearing large caniniform teeth and a gap between their snout bones. In order to test how those peculiarities related to their ecological role as hypercarnivore predators, we digitally reconstructed their skulls using computed tomography (CT-scan) and conducted a type of analysis, called Finite Element Analysis, used by engineers to assess strengthnesses and weaknesses of a structure.
The image on the left shows digital models of (top to bottom) Baurusuchus, Allosaurus and Alligator
When we compared its bite force to other hypercarnivores it didn't really looked like an apex predator: Baurusuchus' bite was 2/3 that of a modern crocodyle and almost 100x weaker than that of a theropod dinosaur! So, it likely on hunting strategies that didn't depend much on strong bites. We then simulated alternative scenarios, such as head shake or head roll biting, and showed that Baurusuchus most likely used a bite and pull-back hunting style to capture its preys.
The figure above shows the stress distribution during bite movements on each model simulated in this study.
Check out this cool animation our coauthor, Dr. Stephan Lautenschlager, made:
This study was published today in Journal of Anatomy and you can see it here.
Source: Montefeltro FC, Lautenschlager S, Godoy PL, Ferreira GS, Butler RJ. 2020. A unique predator in a unique ecosystem: modelling the apex predator within a Late Cretaceous crocodyliform-dominated fauna from Brazil. Journal of Anatomy, doi: 10.1111/joa.13192.