Achelousaurus ‭(‬Achelous’s lizard‭)

Achelousaurus is a genus belonging to the centrosaurine, ceratopsid dinosaurs that was present during the Late Cretaceous Period of what is today North America, about 74.2 million years ago. The genus was discovered through a handful of specimens made mostly of skull material from individuals, which range from infants to adults.

Achelousaurus was estimated to have been 6 meters (20 feet) long and had an estimated weight of 3 tonnes (3.3 small tons). It was a ceratopsian that walked on four feet, had an elongated tail, and a big head with a beak that was hooked. It featured a pair spikes that curved toward the outside and rough bosses just above the eyes and on the snout.

Achelousaurus was a centrosaurine that had horns in the same places as other centrosaurines. It is believed to be the direct descendant of Genus Einiosaurus and was the closest ancestor to Pachyrhinosaurus. It is found in the Two Medicine Formation and lived on an island in Laramidia. It was an herbivore and believed to possess a large metabolic rate, but less than birds and mammals of today. Researchers have speculated these bosses could have been utilized for fighting, with animals fighting their heads against each other in addition to for display purposes.