Insights into the anatomy and functional morphology of durophagous mosasaurines (Squamata: Mosasauridae) from a new species of Globidens from Morocco

Abstract

Abstract Durophagous mosasaurs are rare members of Late Cretaceous marine faunal assemblages and new fossil discoveries can shed light on their anatomy, functional morphology and evolutionary history. Here we describe a new species in the durophagous genus Globidens from the Maastrichtian phosphate deposits of Morocco, based on a partial disarticulated skull and cervical vertebral series. This new species shares many anatomical similarities with the only other described Maastrichtian species, G. phosphaticus, but differs in several key features, including the absence of pronounced swellings and sulci on the crushing teeth and the absence of cervical zygosphenes and zygantra. Histological thin sections of a rib from the holotype show that this was not a juvenile individual and reveal osteosclerotic-like bone compactness for the first time in a paddle-bearing mosasaurine. We interpret the highly compact ribs, as well as several peculiarities of the temporal arcade and lower jaws, as adaptations to a diet of benthic, hard-bodied prey.