The Achelousaurus is known for its large bony frill, which it likely used to attract mates, intimidate predators, and regulate its body temperature. Instead of the typical ceratopsian horns, the Achelousaurus had rough bosses above its eyes and snot. It had a large head with a hooked beak and a heavily built body nearly the size of a Triceratops.

Key Facts

Achelousaurus pronunciationah-kell-oo-saw-rus
What does Achelousaurus mean?Achelou’s Lizard
Dinosaur typeCeratops
On the menuHerbivorous
Length6 meters
Height2.3 meters
Weight2.5 tons
Life expectancyUnknown
Legs used to get aroundQuadrupedal
Estimated top speedUnknown
When they livedUpper Cretaceous era, 74 million years ago
Where they have been found?USA

When & Where

The first Achelousaurus fossil was discovered in 1987 by a team led by Jack Horner in the Two Medicine Formation of Montana, USA. The genus name, Achelousaurus, was a reference to the Greek god of rivers and freshwater, Achelous. Its specific name, horneri, honors Jack Horner who discovered the first fossils.

Size & Weight

The Achelosaurus was a relatively large dinosaur, measuring roughly 6 meters (20 feet) long and weighing about 2.5 tons. It was roughly about the same size as a large SUV! Its head made up about one-third of its total body length, taking up close to 2 meters (6.5 feet).

Mobility & Diet

As with other Ceratopsia like Aquilops and Torosaurus, the Achelosaurus was quadrupedal, meaning it got around on four legs. It was a herbivore and would have used its beak and teeth to bite off plants and crunch through tough vegetation.

Interesting Points

  • The Achelousaurus grew an elongated bony crest above its nose, which is thought to have helped attract mates and intimidate rivals.
  • Typical of ceratopsids, the beak of the Achelousaurus was parrot-like to bite off tough plants.

Featured Image Credit: Karkemish, CC BY-SA 3.0, via Wikimedia Commons