Pachycephalosaurian dinosaur — Stegoceras validum

Geologic period: Late Cretaceous — Campanian

Age: Late Cretaceous, Campanian.

Feeding: Likely herbivorous or omnivorous; exact diet remains less certain than in heavily specialized herbivores.

Locomotion: Bipedal terrestrial locomotion.

Body plan: Small bipedal ornithischian with a thickened skull roof.

Evidence: Skull thickness is direct evidence. Head-butting behavior is interpretation.

Why it matters: Stegoceras is perfect for showing the difference between an anatomical fact—a thick skull roof—and a behavioral hypothesis about what that structure was used for.

Plain Language Identity: A small dome-headed pachycephalosaurid dinosaur from the Late Cretaceous.

What You Are Looking At: A cast based on skull material of Stegoceras validum.

Defense Or Attack: The thick skull dome may have been involved in display or physical combat, but exact behavior remains debated.

Ecosystem: Campanian terrestrial environments of Alberta.

Formation: Oldman Formation for documented Smithsonian material.

Find Location: Alberta, Canada.

Preservation: Visitor object is a cast.

Open Questions: Do not present head-butting as directly observed fact.

Source Urls: https://naturalhistory.si.edu/visit/virtual-tour/current-exhibits/deep-time-virtual-tour-fossil-list; https://www.si.edu/object/nmnhpaleobiology_3440919

Enrichment Method: SAGE curated research pass; title + scientific name + source scene matched; comparative chronology retained; evidence separated from inference

Scientific name: Stegoceras validum

Evidence / representation: comparative_taxon_visual

comparative_taxon_visual

Cretaceous Worlds: Dinosaurs at Their Most Diverse.

Media license: CC BY-SA 2.0

https://creativecommons.org/licenses/by-sa/2.0