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 .R. L. Carroll. (1988). Vertebrate Paleontology and Evolution 1-698 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.F. Ameghino. (1902). Première contribution à la connaissance de la fauna mammalogique des couches à Colpodon [First contribution to the knowledge of the mammalian fauna of the Colpodon Beds]. Boletin de la Academia Nacional de Ciencias de Córdoba 17:71-141 Ameghino in 1902 placed Proschismotherium in the Megatheriidae, alongside Hapaloides, which was its sister taxon.McKenna & Bell (1997) Classification of Mammals Above the Species Level
The holotype jaw was compared to that of Schismotherium fractum and was found to be roughly the same size, indicating that Proschismotherium weighed roughly and grew up to ; the size estimate was loosely based on Hapalops and also Schismotherium.
References