Whereas the land-to-sea transition is well-documented in many secondarily aquatic
mammals, the fossil record of stem pinnipeds is relatively sparse, offering few well-
preserved transitional fossils. Due to this paucity of transitional pinniped forms, it remains
unclear how such divergent locomotory modes and associated morphologies evolved within
pinnipeds. In 2009, Rybczynski et al. reported the discovery of Puijila darwini, a putative
stem pinniped from the Miocene of Canada's high arctic. A brief description of Puijila was …