What is "plionarctos"

Plionarctos is an extinct genus of mammals of the family Ursidae (bears) endemic to North America and Europe during Miocene through Pleistocene, living from ~10.3—3.3 Mya, existing for about 7 million years.

Indarctos (10.7—9.2 Mya) preceded Plionarctos by only a few thousand years and was a contemporary of that bear and shared its habitat. Plionarctus preceded and was also contemporary with Tremarctos floridanus (4.9 million — 11,000 years ago) and shared its habitat.

Plionarctos is the oldest known genus within the subfamily of the short-faced bears ( Tremarctinae) endemic to the Americas, and is believed to be ancestral to the clade.