Pliometanastes


Pliometanastes is an extinct genus of giant ground sloths of the family Megalonychidae endemic to North America during the Late Miocene epoch through very early Pliocene epoch. Its fossils have been found in Costa Rica and across the southern United States from California to Florida.

Description

Pliometanastes and Thinobadistes were the first of the giant sloths to appear in North America, the former around 9 million years ago. Both were in North America before the Panamanian Land Bridge formed around 2.7 million years ago, which led to the main pulse of the Great American Interchange. It is then reasonable to presume that the ancestors of Pliometanastes island-hopped across the Central American Seaway from South America, where ground sloths arose.
Pliometanastes gave rise to Megalonyx. Their closest extant relatives, based on molecular results are the extant arboreal three-toed sloths.

Taxonomy

Pliometanastes was named by Hirschfeld and Webb. Its type is Pliometanastes protistus. It was assigned to Megalonychidae by Hirschfeld and Webb and Carroll.

Fossil distribution

Sites and ages of specimens :