Proschismotherium fossil map
Where fossils of Proschismotherium have been found, shown on the Earth as it looked about 15 million years ago and on today’s map.
Dots are fossil collections recorded in the Paleobiology Database. The “then” view moves today’s fossil sites back to their positions 15 million years ago (the time slice nearest the median age of the fossils) using the Merdith et al. (2021) plate model; positions are approximate. Open on the timeline map →
| Group | Early mammals |
|---|---|
| Lived | 21–17.5 million years ago (Aquitanian to Burdigalian) |
| Periods | Neogene |
| Family | Megalonychidae |
| Named by | Ameghino 1902 |
| Fossil records | 2 occurrences at 1 locations (PBDB) |
| Found in | Argentina |
| Rock formations | Sarmiento |
About 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. 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. Ameghino in 1902 placed Proschismotherium in the Megatheriidae, alongside Hapaloides, which was its sister taxon.
The holotype jaw was compared to that of Schismotherium fractum and was found to be roughly the same size, indicating that Proschismotherium weighed roughly 45 kilograms (99 lb) and grew up to 1 metre (3.3 ft); the size estimate was loosely based on Hapalops and also Schismotherium.
Text in “About” is quoted from the Wikipedia article Proschismotherium (revision 1354888511), licensed under CC BY-SA 4.0; introduction excerpted verbatim, formatting removed. Ages, family, authority and fossil records: Paleobiology Database, accessed 23 October 2026. Ages are those of the rock layers the fossils were found in. Wikidata: Q104178020.
