Ecological Adaptations of Mandibular Form in Fissiped Carnivora

Among mammals, Carnivora presents an ideal group for investigating the complex interplay between functional adaptation and phylogenetic history. Here we explore mandibular form and its relationship to ecology and phylogeny using geometric morphometrics applied to mandibles of extant Carnivora. Both mandibular size and shape discriminate carnivoran ecological adaptations (diet, membership to small or large predatory guilds), but the interplay of morphology with phylogenetic history is profound. In general, families do not overlap in mandible shape; however, Viverridae, Herpestidae, Canidae, and Mustelidae exhibit functional and morphological convergence. Mandibular allometric trajectories are distinct among families and ecological categories. Our findings suggest that variability in mandibular form among Carnivora is primarily influenced by major evolutionary changes occurring at the family level and less, but significantly so, by ecological adaptations. Small generalist feeders (insectivores, omnivores) exhibit stronger convergence in mandibular shape than highly specialized predators; bigger taxa, such as bears, evolved unique morphologies constrained by allometric scaling. Thus, the findings of this study serve to demonstrate how ecological factors mold anatomical structures in similar ways to serve similar functions. As such, carnivoran species can be usefully grouped into functional ‘guilds’ in eco-morphological studies irrespective of their phylogenetic history.