Andrewsarchus

Andrewsarchus Fossil range: Eocene
The only skull of Andrewsarchus, on display at the American Museum of Natural History in New York City.
Biological classification
Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: †Mesonychia Family: †Triisodontidae Genus: †Andrewsarchus Pao, 1923
Species
A. mongoliensis Pao, 1923 (type)

Andrewsarchus mongoliensis (Andrews + Greek ἀρχός, "ruler"), was a mammalian Mesonychid predator.

This large heavily-built, wolf-like, mammal lived during the Eocene, about 45 to 36 million years ago. It walked on four short legs and had a long body, a long tail, and feet with hoofed toes. It had a long snout with large, sharp teeth and flat cheek teeth that may have been used to crush bones.

Because Andrewsarchus is only known from a skull and a few other bones, whether it was an active predator or merely a large scavenger is open to debate, as is its exact time range.

Reconstruction of A. mongoliensis