Evolution, morphological diversity and dietary signal in the carnassial teeth of Pan-Carnivorans

Abstract

Mammalian dental morphology is remarkably diverse and complex, providing key insights into various aspects of their biology, including diet, phylogeny, and ontogeny. Within this considerable diversity, some species exhibit morphologies that are strongly derived toward increased sectorial efficiency; these teeth are known as carnassial teeth. This master thesis focuses on the morphology of carnassial teeth of Pan-carnivorans and (1) aim to quantify their morphological diversity and (2) the evolution of this diversity trough time as well as (3) to assess the dietary signals they contain. To achieve this, we used high-density landmarking methods on 3D models of carnassial teeth from 250 species of extant and fossil animals. Surface scans of more than 100 specimens were realised exclusively for this thesis, while the remaining models were shared with us by institutions from all over the world. Our results show that carnassial teeth carry significant dietary information, although the precision of possible dietary inferences is clade-specific. We also describe how the 'Grande Coupure' and associated Oligocene migration events caused remarkable perturbations in the dental phenotypes of large predators, leaving lasting effects that are still visible in modern ecosystems with the dominance of canids and felids in hypercarnivores guilds. Furthermore, we demonstrate that highly derived dental morphology associated with hypercarnivory – so called ‘hypercarnassialised’ teeth - has been a consistent feature of mammalian diversity since the Eocene, evolving independently in multiple lineages with no discernible temporal gaps. This study advances our understanding of the evolutionary dynamics of Pan-carnivorans and provides valuable insights into the paleoecology and predator-prey dynamics throughout the Cenozoic era.