Tetraceros

Tetraceros is a genus of extinct pronghorn that lived in North America during the Pliocene and Pleistocene epochs. The most well-known species is Tetraceros major, meaning "four-horned great," a name reflecting its most distinctive feature: the presence of four horns. Unlike modern pronghorn, which have only two horns, Tetraceros possessed a pair of smaller brow tines in addition to the main ossicones. This unusual cranial ornamentation sets it apart from its living relatives and other extinct artiodactyls.

Fossil evidence suggests that Tetraceros was an herbivore, likely feeding on grasses and other vegetation. Its skeletal structure indicates it was a relatively swift runner, adapted to open grasslands, similar to its modern descendant. The discovery of Tetraceros fossils has provided valuable insights into the evolutionary history of the pronghorn family, highlighting periods of greater diversity and unique adaptations within the group. The exact reasons for the evolution of the four horns and their subsequent disappearance in later pronghorn lineages remain a subject of scientific investigation, possibly related to sexual selection or intraspecific competition. The genus Tetraceros is now extinct, with no direct living descendants possessing the four-horned characteristic.