Bolton, Andrew2025-06-202024-08Bolton, Andrew. (2024). Finite Element Analysis of Dinocephalian Skulls to Address Head-Butting Behaviour in Early Therapsids. [Master's dissertation, University of the Witwatersrand, Johannesburg]. WIReDSpace. https://hdl.handle.net/10539/45189https://hdl.handle.net/10539/45189Research project submitted in fulfilment of the Bachelor of Science with Masters in the field of Palaeontology in the Faculty of Science, School of Geoscience, University of the Witwatersrand, Johannesburg, 2024.The origin of complex social behaviour in the mammalian lineage has been a long-standing enigma. Behaviours do not leave a rich fossil record; however, adaptations to highly specialised complex behaviour can be traced back in some lineages, such as the dinocephalians. Dinocephalians dominated carnivorous and herbivorous niches of terrestrial ecosystems in the Middle Permian (~273-259 million years ago). Species within this clade often have skulls with considerable pachyostosis (overly thickened bones) and cranial ornamentation (horns and bosses). This morphology has been interpreted as evidence for head-butting, but the evidence is circumstantial at best. For this project, I used three-dimensional models of the skulls of four dinocephalians and two outgroups to simulate and investigate the capabilities of these skulls to withstand different magnitudes of head-butting and flank-butting impacts with finite element analyses. Palaeopathological analyses vindicated the accuracy of FEA data, which indicates that dinocephalian skulls modelled here arguably reflect biological truth. As head-butting is a complex social behaviour, this would strongly suggest the presence of dominance hierarchies, territoriality, and gregariousness. This represents the earliest robust evidence of complex social behaviour in tetrapods, preceding all known examples of social interactions in dinosaurs and mammals by hundreds of millions of years.en©2024 University of the Witwatersrand, Johannesburg. All rights reserved. The copyright in this work vests in the University of the Witwatersrand, Johannesburg. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of University of the Witwatersrand, Johannesburg.PalaeontologyTherapsidsDinocephaliansFinite element analysisPalaeopathologyUCTDDissertationUniversity of the Witwatersrand, JohannesburgSDG-15: Life on landSDG-4: Quality education