Dinosaurs · Small ornithopod

Thescelosaurus

Say it thes-kel-oh-SORE-us. The name means ‘wonderful lizard’.

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

Length: 3.5 m
Diet: Plant-eater
When: Late Cretaceous76 to 66 million years ago
Fossils found in: Canada, USA
Named by: Gilmore (1913)
Family tree: Dinosauria › Ornithischia › Ornithopoda › Euornithopoda

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

Small ornithopods. Small, fast, two-legged plant-eaters. See all 12

Lived at the same time

Dryptosaurus · same country
Edmontosaurus · same country
Chirostenotes · same country
Ornithomimus · same country
Achelousaurus · same country
Euoplocephalus · same country
Pachyrhinosaurus · same country
Arrhinoceratops · same country

Other small ornithopods

Parksosaurus Late Cretaceous
Orodromeus Late Cretaceous
Zalmoxes Late Cretaceous
Gasparinisaura Late Cretaceous
Oryctodromeus Late Cretaceous
Leaellynasaura Early Cretaceous
Zephyrosaurus Early Cretaceous
Atlascopcosaurus Early Cretaceous

Source: Thescelosaurus 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.