Plionarctos

Plionarctos is an extinct genus of bear endemic to North America from the Miocene to the Pliocene, ~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. Plionarctos 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), and is believed to be ancestral to the clade.

Fossil distribution
Sites and specimen ages:
 * Ile de Ratonneau Breccia, Provence, France about ~800,000—100,000 years ago
 * Fort Green Mine, Polk County, Florida paleontological sites about 10.3—4.9 Mya
 * Taunton site, Adams County, Washington (P. harroldorum) about 4.9—1.8 Mya (Plionarctos harroldorum)
 * Pipe Creek Sinkhole, Grant County, Indiana (P. edensis) about 10.3—1.8 Mya
 * Palmetto Mine, Polk County, Florida 7.9—7.8 Mya
 * Gray Fossil Site, Washington County, Tennessee about 7.0-4.5 Mya