CONICET | Buscador de Institutos y Recursos Humanos

Non-crocodylomorph loricatans, traditionally known as rauisuchians, are considered as the top predators of the Triassic continental faunas that reigned before the emergence of the well-known theropod dinosaurs. In particular, Saurosuchus galilei is a large quadrupedal prestosuchid loricatan found in the Ischigualasto Formation from northwestern Argentina. Here we reevaluated the braincase of Saurosuchus galilei and present the first paleoneurological study based on the partial natural casts of the holotype and the digital cranial endocast of the referred specimen PVSJ 32. The braincase of Saurosuchus galilei was here reinterpreted identifying the sutures of the supraoccipital, otoccipital, basioccipital, parabasisphenoid, prootic, and laterosphenoid. A unique feature identified in the braincase of Saurosuchus galilei is the presence of deep paracondylar recesses associated with pharyngotympanic pneumaticity, which has not been identified in any other rauisuchians so far. Most of the structures of the encephalon were recognized in the cranial endocast and natural casts including cranial nerves V-XII, olfactory bulbs, main blood vessels and sinuses, and inner ear. These structures allowed us to quantify some of its sensorial capacities and recognize that Saurosuchus galilei had an enhanced olfactory acuity, with coefficients higher than those expected for its body size, a condition previously observed in living crocodilians and tyrannosaurid dinosaurs. An improved sense of smell might have allowed Saurosuchus to track its prey from long distances and compensate for the poorer development of other senses like its vision and balance.

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