Phylogenetic Relationships within the Phocoid Pinniped Clade

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Pinnipeds are an important group of marine mammals, comprising the walruses, sea lions, and seals. Nevertheless, their evolutionary relationships to each other and to other mammals remain unclear. Dr. Annalisa Berta is a vertebrate paleontologist studying the anatomy of fossil and living pinnipeds for the purpose of reconstructing their evolutionary history. Her research also considers the functional capabilities of fossilized species, providing unique insight into the evolution of behavior in the group, and its transformation from terrestrial ancestors. Dr. Berta proposes to continue her investigations into the evolutionary relationships among pinnipeds using morphological data from fossils. The present project will focus on the phocids, a possible sister-group to the walruses. Cranial and post-cranial material from the Oligocene- Miocene of coastal Oregon will be examined, and locomotor capabilities (principally forelimb versus hindlimb propulsion) estimated. This project represents a logical extension of a previous award that supported study of the otarioid pinnipeds (walruses, sea lions, but not seals). The proposed research has implications for a wide scientific audience. Comparative anatomists and vertebrate zoologists will welcome the new data derived from early Tertiary fossils, along with new reconstructions of evolutionary relationships of major mammalian groups. Functional morphologists will look to this study for critical information on alternative adaptations to life in aquatic habitats. Evolutionary biologists will integrate these findings with recent results based on DNA sequence data, resulting in an unusually detailed understanding of this noteworthy group.