Machaeroides ("dagger-like") is a genus of sabre-toothed predatory mammal that lived during the Eocene (54.9 to 46.2 mya). Its fossils were found in the U.S. state of Wyoming.
Both species bore a passing or superficial resemblance to a very small, dog-sized saber-toothed cat. Machaeroides could be distinguished from actual saber-toothed cats by their more-elongated skulls, and their plantigrade stance. Machaeroides species are distinguished from the closely related Apataelurus by the fact that the former genus had smaller saber-teeth. Despite its small size, the genus Machairoides was well-equipped to hunt prey larger than itself, such as the small, primitive horses and rhinoceroses present at the time, as it was equipped with saber teeth and powerful forelimbs to subdue prey.[3]
M. eothen weighed an estimated 10–14 kg (22–31 lb), thus matching in size a small Staffordshire Terrier. M. simpsoni was probably smaller.[4]
Its position within the mammals has been in dispute. Experts have been equally divided over whether Machaeroides and its sister-genus, Apataelurus, belong in Oxyaenidae or Hyaenodonta, though the most recent studies favor the former.[5]
The phylogenetic relationships of the genus Machaeroides are shown in the following cladogram.[6][7][8][9]