Dinosaurs A to Z
Ceratopsidae

Achelousaurus horneri pronuh-kiːloʊ-sɔːruhs,_-akih-lohuh-SƆːRUHS

Generic ceratopsian body-plan outline
You 1.8 m (5.9 ft) tall
Achelousaurus 6 m (19.7 ft) long
as long as 4 people standing fingertip to fingertip
generic ceratopsian body plan, scaled to length — not a silhouette of Achelousaurus
Length
6 m (19.7 ft)
Period
Late Cretaceous (77–74.8 Mya)
Place
North America · Montana, USA
Food
Herbivore
Clade
Ceratopsidae Dinosauria Ornithischia Cerapoda Marginocephalia Big horned ceratopsians of the Late Cretaceous.

Achelousaurus () is a genus of centrosaurine ceratopsid dinosaur that lived during the Late Cretaceous Period of what is now North America, about 77 to 74.8 million years ago. The first fossils of Achelousaurus were collected in Montana in 1987, by a team led by Jack Horner, with more finds made in 1989. In 1994, Achelousaurus horneri was described and named by Scott D. Sampson; the generic name means “Achelous lizard”, in reference to the Greek deity Achelous, and the specific name refers to Horner. The genus is known from a few specimens consisting mainly of skull material from individuals, ranging from juveniles to adults.

A large centrosaurine, Achelousaurus supposedly was about 6 m long, with a weight of about 3 MT. As a ceratopsian, it walked on all fours, had a short tail and a large head with a hooked beak.

What we know

  • Named by Sampson, 1994.
  • Body length estimated at about 6 m.
  • Fossils found in North America and Montana, USA.

What we guess

The reconstruction notes for Achelousaurus — soft tissue, color, behavior — haven't been written up yet. Only the recorded basics above are filled in so far.