Enaliarctos has been heralded as the ancestor of all known pinnipeds, including the families
Otariidae (fur seals and sea lions),
Desmatophocidae (extinct seal convergent pinnipeds),
Phocidae (true seals), and
Odobenidae (walruses). Investigations of the biomechanics of
Enaliarctos indicate that it used both its forelimbs and hindlimbs during swimming. Modern fur seals and sea lions only use their forelimbs, while true seals primarily use their hindlimbs for aquatic propulsion; lastly, the extant walrus uses both fore- and hindlimbs for swimming. It has been postulated that the condition in
Enaliarctos is ancestral for all pinnipeds, and that forelimb swimming was lost in true seals, while hindlimb swimming was lost in fur seals and sea lions. This is significant because there has been considerable debate as to whether pinnipeds share common ancestry. Interpretation of
Enaliarctos indicates that all pinnipeds share a common ancestor (which, if it was not
Enaliarctos, must have been something very similar, such as the more recently discovered
Puijila, of controversial affinities, though).
(background)Enaliarctos emlongi'' is represented by
fossils from coastal
Oregon. It existed between 13 and 20 million years ago, during the
Hemingfordian age of the
Miocene epoch. It was named for renowned fossil collector
Douglas Emlong in 1991 by paleontologist
Annalisa Berta. ==Notes==