Plionarctos
Introduction '''''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
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