Archaeotherium

Archaeotherium Temporal range: Late Eocene to Early Oligocene
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Archaeotherium mortoni skeleton
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Artiodactyla
Family:	†Entelodontidae
Genus:	†Archaeotherium Leidy (1850)

Archaeotherium (Greek: αρχαιοθήριον, meaning "ancient beast") is an extinct genus of entelodont artiodactyl endemic to North America during the Eocene and Oligocene epochs (38—24.8 mya), existing for approximately 6 million years. Archaeotherium was about 1.2m tall at the shoulder and around 2m long and weighing around 270 kg.

Although superficially pig-like, Archaeotherium, along with all other entelodonts, was more closely related to anthracotheres, hippopotamuses, and whales. Evidence from the Wyoming Dinosaur Center suggests that the omnivorous Archaeotherium, like many modern predatory mammals, kept caches of food for times when their hunting was less successful.

Taxonomy

File:Archaeotherium.jpg

Archaeotherium eating a root

Archaeotherium mortoni skull

Archaeotherium was named by Leidy (1850). Its type is Archaeotherium mortoni. It was synonymized subjectively with Entelodon by Joseph Leidy (1853) and synonymized subjectively with Elotherium by Leidy (1857). It was assigned to Entelodontidae by Leidy (1850), Peterson (1909), Scott (1940), Galbreath (1953), Russell (1980), Carroll (1988) and Effinger (1998).

Morphology

In life, Archaeotherium probably resembled a large, fanged, cow-sized peccary with bumps projecting from the side of its head. It had high shoulders, presumably to carry strong neck muscles to support the heavy head. The brain was tiny, but had relatively large olfactory lobes, suggesting that the animal had a keen sense of smell.

The largest (and type) species, A. mortoni was a cow-sized predator. Rhino jaws and other mammal bones have been found with bite marks on them that match the large canines of A. mortoni. A fossil trackway in Toadstool Geologic Park depicts the path of a Subhyracodon walking forward, stopping to see an Archaeotherium approach, then breaking into a gallop with the entelodont chasing after it. In leaner times, it is suggested that Archaeotherium dug for roots and tubers, as with other pig-like mammals.