Plionarctos

Plionarctos is an extinct genus of short-faced bear endemic to North America from the Late Miocene to the Pliocene.

== Taxonomy == Described by Childs Frick in 1926, Plionarctos is the oldest known genus within the subfamily of the short-faced bears (Tremarctinae),'''' and is believed to be ancestral to Arctodus, Arctotherium and Tremarctos. Once suggested to have emerged from the Ailuropodinae bears (Agriotherium and Indarctos), Plionarctos probably evolved from Ursavus which emigrated into North America from Eurasia during the Miocene, or possibly Protarctos. A new species, Plionarctos harroldum, was described in 2001 from the White Bluffs Fauna in Washington from remains previously attributed to Protarctos abstrusus. Middle Pleistocene species from France were described (Plionarctos stehlini and Plionarctos telonensis) but have since been reassigned & synonymized with the Asian black bear (Ursus thibetanus).