Tetrameryx

Tetrameryx is an extinct genus of the North American artiodactyl family Antilocapridae, known from Mexico, the western United States, and Saskatchewan in Canada.

Taxonomy
The name means "four [horned] ruminant", referring to the division of each horn near its base into two prongs; in T. shuleri, the rear prong is much longer. 5 species are known.

Description
One member of the genus, T. shuleri, survived until about 12,000 years ago, and was present when Paleo-Indians reached North America. Although approximately the same size as the living pronghorn, the limb bones are somewhat more robust, suggesting that its running speed was slower than living pronghorn.