Dinosaurs · Ceratopsian

Achelousaurus

Say it ah-KEL-oo-SORE-us. The name means ‘Achelous lizard’.

Achelousaurus beside a person 1.75 m tall. Ticks mark every metre.Body shape drawn for this site, showing the general build of ceratopsians

Length: 6 m
Diet: Plant-eater
When: Late Cretaceous83 to 70 million years ago
Fossils found in: USA
Named by: Sampson (1995)
Family tree: Dinosauria › Ornithischia › Ceratopsidae › Centrosaurinae

Where Achelousaurus sits in the age of dinosaurs.Periods from the ICS chart; dinosaur dates from the Natural History Museum

Ceratopsians. Horned and frilled plant-eaters, such as Triceratops. See all 29

Lived at the same time

Dryptosaurus · same country
Bambiraptor · same country
Gryposaurus · same country
Lophorhothon · same country
Gorgosaurus · same country
Euoplocephalus · same country
Thescelosaurus · same country
Albertaceratops · same country

Other ceratopsians

Micropachycephalosaurus Late Cretaceous
Bagaceratops Late Cretaceous
Udanoceratops Late Cretaceous
Albertaceratops Late Cretaceous
Avaceratops Late Cretaceous
Microceratus Late Cretaceous
Centrosaurus Late Cretaceous
Chasmosaurus Late Cretaceous

Source: Achelousaurus in the Natural History Museum Dino Directory, read 12 November 2026. Sizes are the museum's estimates for a typical adult. "Lived at the same time" lists dinosaurs whose dates overlap, which does not always mean they met.