Inner skull cavities of the basal eusuchian Lohuecosuchus megadontos (Upper Cretaceous, Spain) and neurosensorial implications

Abstract

The Late Cretaceous fossil site of Lo Hueco (Cuenca, Spain) has yielded a large collection of tetrapod remains, in which crocodyliforms are one of the best represented groups. The crocodyliforms from Lo Hueco helped establish Allodaposuchidae as one of the sister-groups of Crocodylia. A complete skull of the holotype of the allodaposuchid Lohuecosuchus megadontos was CT scanned, and all its inner cavities, including those of the brain, nerves, inner ear and blood vessels, as well as the paratympanic sinus system and the paranasal sinuses, were three-dimensionally reconstructed and compared to those of several extant and extinct crocodylians. The endocranial anatomy of Lohuecosuchus megadontos is congruent with its phylogenetic position as a basal eusuchian. Our work suggests that some of the neurosensorial capabilities found in the crown-group Crocodylia such as an acute sense of olfaction and a low frequencies hearing are already present at the base of Eusuchia.