Estimating the endocranial volume and body mass of Anteosaurus, Jonkeria, and Moschops (Dinocephalia, Therapsida) using 3D sculpting

Abstract

Dinocephalians represent a highly successful early radiation of mid-Permian the-rapsids. Despite the abundance of their fossils, data on their paleoneurology is chal-lenging to acquire and remain scarce. The current study proposes to overcome these challenges by using digital 3D sculpting. Based on previous works, realistic digital models of brain endocasts and live reconstructions of three taxa sampling the major families of Dinocephalia (Anteosauridae, Titanosuchidae, and Tapinocephalidae) were generated, their volumes measured, and endocranial volume and body mass were estimated. Encephalization quotients were calculated. The results suggest that the dinocephalians evolved a surprisingly high degree of encephalization for such early tet-rapods. Some dinocephalians are hypothesized to have practiced head-butting, a com-plex social behavior, which would have favored the enlargement of the brain. Alternatively, the enlarged endocast may have been filled mostly by protective tissue to protect the central nervous system when the head was used as a weapon. This is sup-ported by the apparent absence of direct imprints of the soft tissue of the brain on the endocast.