Meeting Abstract
The adaptive radiation of mammals has led to distinct cranial and dental morphologies that often correlate, across taxa, with feeding niches. Amphicyonids (colloquially called “bear-dogs”) remain enigmatic in their paleobiology and taxonomy; it is the last clade with an unknown position in Carnivora. In this study, we use CT-based, 3D cranial finite element models of Daphoenus (Amphicyonid), Tremarctos ornatus (spectacled bear) and Canis lupus (gray wolf) to compare bite efficiency and skull strain energy to determine whether Daphoenus is more similar in biomechanical capability to Ursidae or Canidae. Finite element analysis in a phylogenetic context allowed for reconstruction of feeding specialization and tested for the influence of evolutionary history and diet on craniodental morphology. In prior studies using comparative finite element analysis, strain energy levels corresponded with taxonomic groupings rather than ecomorphology, while combined bite efficiency and strain energy measurements distinguished between hypercarnivores and generalists. A strain energy and bite efficiency comparison with Canis lupus tested for hypercarnivory in Daphoenus as compared to basal Caniformia. Comparison with Tremarctos ornatus, the earliest diverging living ursid, tested for generalist biomechanics in Daphoenus and symplesiomorphic biomechanical features suggested by retained ancestral traits. Comparison of bite simulation outputs shows similarities in biomechanical capability of Daphoenus to both Tremarctos and Canis. Daphoenus diverges from Tremarctos and Canis leaning toward an intermediary, and potentially plesiomorphic, type of skull mechanics distinct from attributes typically observed in hypercarnivores or omnivores.
