Liarthrus fossil map
Where fossils of Liarthrus have been found, shown on the Earth as it looked about 30 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 30 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 | 29–21 million years ago (Rupelian to Aquitanian) |
| Periods | Paleogene, Neogene |
| Family | Astrapotheriidae |
| Fossil records | 4 occurrences at 2 locations (PBDB) |
| Found in | Argentina |
| Rock formations | Deseado, Sarmiento |
About Liarthrus
Liarthrus ("smooth joint") is a genus of astrapotheriid mammal known from the Late Oligocene (Deseadan SALMA, around 29–21 mya) Sarmiento Formation of Santa Cruz Province, Argentina. It was described by the Argentine paleontologist Florentino Ameghino in 1895 along with several other genera from the "Pyrotherium Beds", which were then believed to date to the Cretaceous period. Ameghino described Liarthus on the basis of fragmentary specimen, consisting of only a right astragalus (tarsal bone), premolar 4, and an incomplete premolar from the upper jaws. Only one species was described, L. copei, the species name honoring the American paleontologist Edward Drinker Cope, who lived at the same time as Ameghino. Liarthrus was synonymized with the other astrapothere Parastrapotherium in 1914 by American mammalogist Frederic Loomis, though it was revalidated by a 2008 analysis of Parastrapotherium. Liarthrus was a herbivorous mammal, being an astrapothere, which had large tusks on their skulls and mandibles in addition to a large body size.
Text in “About” is quoted from the Wikipedia article Liarthrus (revision 1282471933), 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: Q119471644.
