A multi-method approach to deciphering the paleobiology of a mosasaur from South Africa

This is the authors' abstract. We don't add key points for this paper.

This study presents the first paleobiological investigation of a cf. Prognathodon mosasaur (CGP/1/2265) from South Africa. It focuses on a fragmentary tooth extracted from the matrix around the muzzle unit, which was of low taxonomic value but offered an opportunity to perform a multi-method analysis including strontium dating, micro-CT scanning, tooth histology, SEM, EDS, and oxygen isotope analysis. Application of these multiple techniques yielded much insight into the paleobiology of this individual. The strontium isotope analysis on the tooth enamel has been reported in another earlier publication and provided a date of the specimen around 67 Ma. Micro-CT scanning and histology revealed enamel wear on the apical regions of the tooth, a small pulp cavity, no calcified periodontal ligament, and Howship's lacunae, suggesting it was a shed tooth that was likely still “superficially” attached to the gum tissue at the time of death. SEM revealed prismless enamel and small spherical structures comprised mostly of CaCO3, likely ooids, on the dentine and within the dentine tubules. Other possible classifications of these spheres are explored. Oxygen isotope composition (δ18O) of the tooth enamel was used to estimate the cf. Prognathodon specimen body temperature by comparing it with the δ18O value of a closely associated Squalicorax shark tooth. The results suggest that this cf. Prognathodon maintained a body temperature warmer than that of the shark and likely warmer than the surrounding seawater. Acknowledging the limitations from data obtained from one specimen, this study demonstrates how a single fragmentary tooth has increased our understanding of this specific cf. Prognathodon from Pondoland in South Africa, and mosasaurs in general.