Pliometanastes is an extinct genus of giant ground sloths of the family Megalonychidae endemic to North America during the Miocene epoch through very early Pliocene epoch. Its fossils have been found across the southern U. S. from California to Florida. Pliometanastes gave rise to Megalonyx. Their closest extant relatives are the two-toed arboreal sloths (Choloepus).