HOLLIDAY, J.A.: Evolution of Hypercarnivory: The effect of specialization on character change

In mammalian carnivores, hypercarnivory is characterized by specific morphological changes including elongation of the carnassial blade and reduction of the post-carnassial dentition. The most extreme adaptations to the condition are seen in felids and nimravids, but hypercarnivory has also evolved in mustelids, viverrids, hyaenids and canids. In a general context, it has been argued that possession of some character states may reduce the ability to attain certain other states. More specifically, it has been suggested that the extreme specialization in felids and nimravids may have limited the flexibility of the groups, resulting in a reduced ability to take advantage of open niches. To test the hypothesis that specialization limits adaptive flexibility, I perform sister-group comparisons in each of the above-listed families and then sum results across families. Preliminary results indicate that hypercarnivores as a group do show a reduced frequency of character change. When taxa are categorized and evaluated based on “degree of specialization,” results indicate that less specialized taxa do have a higher frequency of character change. Initial studies utilizing multivariate techniques provide support for these findings.