During the Triassic Period, pseudosuchian reptiles diverged and dominated the terrestrial and semi-aquatic ecosystems. A very successful paraphyletic pseudosuchian grade were a group commonly referred to as ‘rauisuchians’. Saurosuchus galilei, first described by Osvaldo Reig over six decades ago, was a hypercarnivorous, quadrupedal rauisuchian that dominated the terrestrial ecosystems in the Late Triassic, about 237 - 208.5 million years ago. Here, the first digital reconstruction of a juvenile, three dimensionally, well-preserved Saurosuchus cranium (PVSJ 32), from the Ischigualasto Formation in Argentina, was carried out. Using finite element analysis (FEA), the morphological function of the Saurosuchus cranium was biomechanically explored, comparing the stress magnitudes and distributions to theropod dinosaurs, including Allosaurus fragilis, in order to assess the functional convergence between Triassic and post-Triassic carnivores. With their large size and morphological similarities to post-Triassic theropods, including dorsoventrally deep skulls and ziphodont (serrated) dentitions, Saurosuchus is suggested to have been a key apex predator and therefore would show analogous stress and bite magnitudes to similarly sized apex theropods. However, this hypothesis disregards functional behaviours that can influence more refined predatory roles. Similar stress magnitudes and distributions between Saurosuchus and Allosaurus were displayed under the same functional simulations, which indicates a somewhat strong skull and functional convergence with theropods to a certain extent. However, higher stresses and a weak bite for its size were also shown (1015–1885 N). This indicates that Saurosuchus potentially consumed softer parts of carcasses, which would mean that it was quite wasteful with its prey, differing to theropods and other pseudosuchians. This analysis increases our knowledge of the functional diversity of pseudosuchians and also highlights the key functional differences between Triassic and post-Triassic apex predators.
