Proschismotherium

Proschismotherium is an extinct genus of ground sloth of the family Megalonychidae, endemic to Argentina during the Early Miocene. It lived from 17.5 mya — 16.3 mya, existing (as a genus) for approximately 1.2 million years.^[1] The type, and only, species, P. oppositum, was named in 1902 by Florentino Ameghino based on a single specimen found in the Santacrucian-aged Colpodon Beds of Argentina.^[2] Ameghino in 1902 placed Proschismotherium in the Megatheriidae,^[2] alongside Hapaloides, which was its sister taxon.^[1][3][4][5]

Proschismotherium Temporal range: Early Miocene, 17.5–16.3 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓ Santacrucian
Holotype jaw
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Pilosa
Family:	†Megalonychidae
Genus:	†Proschismotherium Ameghino, 1902
Species:	†P. oppositum
Binomial name
†Proschismotherium oppositum Ameghino, 1902

The holotype jaw was compared to that of Schismotherium fractum and was found to be roughly the same size,^[2] indicating that Proschismotherium weighed roughly 45 kilograms (99 lb) and grew up to 1 metre (3.3 ft);^[6] the size estimate was loosely based on Hapalops and also Schismotherium.^[7]