THE TOOTH OF THE MATTER: ECOMORPHOLOGY ELUCIDATES COMPLEX EVOLUTIONARY DYNAMICS ACROSS FOSSIL AND LIVING CARNIVORA (Invited Presentation)

The integration of neonotological and palaeontological approaches is acknowledged to be critical for understanding the regulators of biodiversity, so why are there so few examples of studies combining fossil and extant diversity? We explore some of the issues encountered when conducting integrated research illustrated with our work on dietary evolution in mammals. Diet is an important component of the suite traits that ultimately determine how lineages respond to environmental change over evolutionary time. Fossil and modern studies have revealed that carnivorous mammals are more vulnerable to extinction, and risk increases further if they are large and specialize on vertebrate prey (hypercarnivorous). Inspired by these broad-scale patterns, we undertook a detailed investigation of the evolutionary dynamics across fossil and living Carnivora using carnassial tooth morphology. Carnivorans, despite what their name suggests have evolved a wide variety of diets and are well-studied, making them the ideal group to further investigate the macroevolutionary influence of diet. The carnassial teeth are one of the defining features of this order and their shape is expected to reflect diet, as elongate shearing surfaces are more efficient at processing vertebrate flesh, while large crushing basins are more effective at processing plant foods. We quantify morphological differences using geometric morphometric landmarks on the principal cusps of the carnassial teeth and use a phylogenetic framework to reconstruct changes in the carnivoran ecomorphospace over time. Our analyses reveal unexpected patterns in the evolution of tooth morphology and its relationship to diet, as well as the ecological inferences made through time.