Stegoceras validum steg-OSS-eh-ras
"Roof horn"
You 1.8 m (5.9 ft) tall
Stegoceras 2.5 m (8.2 ft) long
2 people holding hands
- Length
- 2.5 m (8.2 ft) — About 2.5 m long, ~40 kg — much smaller cousin of Pachycephalosaurus.
- Period
- Late Cretaceous (77–74 Mya)
- Place
- North America · Alberta, Canada · Montana
- Food
- Omnivore — Plants with possible insects and small animals — varied teeth suggest a mixed diet.
Stegoceras was a small pachycephalosaur with a thinner dome than Pachycephalosaurus, but the same basic head-bashing equipment. Several well-preserved skulls show how the dome grew thicker with age — young Stegoceras had flatter heads. Stegoceras is sometimes mistaken for Stegosaurus by tourists because of the similar name, but they aren’t closely related.
What we know
- Skull dome thickened with age — juveniles had flatter heads.
- Smaller than Pachycephalosaurus, with a less massive dome.
- Lived in the Dinosaur Park Formation, alongside many ceratopsians and hadrosaurs.
- Several well-preserved skulls and partial skeletons known.
What we guess
- Whether the dome was used in combat like Pachycephalosaurus or mainly for display.
- Whether young animals fought differently with their flatter heads.
- Why two pachycephalosaurs coexisted in the same ecosystem — different diets are likely.