Dinosaur genus

Stegoceras

Lambe 1902

Stegoceras is a dinosaur genus known from bones, found in rocks 83.6–66 million years old, in the United States and Canada.

Also calledja ステゴケラス

medium

medium: Only Wikidata gives this; nothing contradicts it.

Confidence labels

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How sure are we?3 high14 medium2 lowHow we rate confidence

Confidence labels are switched off. Facts with low confidence, or where sources disagree, still carry a small dot: tap it for the reason.

At a glance

Data as of 10 October 2026

83.6–66 Ma

Triassic

Jurassic

Cretaceous

252 million years ago20114366

The last non-bird dinosaurs died out 66 million years ago. That's as far from us as the end of this bar.

Named by: Lambe 1902
medium
medium: Only PBDB gives this; nothing contradicts it.
Sources
Given by: Paleobiology Database. How it was chosen: PBDB leads.
Described in: L. M. Lambe (1902). New genera and species from the Belly River Series (mid-Cretaceous). Geological Survey of Canada Contributions to Canadian Palaeontology 3(2): 25–81.
medium
medium: Only PBDB gives this; its author and year match the naming authority (Lambe 1902).
Sources
Given by: Paleobiology Database. The publication the Paleobiology Database gives as the authority for this genus name, usually the one that first named and described it.
Type species: Stegoceras validum
medium
medium: Only PBDB gives this; nothing contradicts it.
Sources
Given by: Paleobiology Database. How it was chosen: PBDB leads.
Lived: Campanian to Maastrichtian, 83.6–66 million years ago
high
high: PBDB and NHM agree.
Omnisaura calculation83.6–66 million years ago, from its dated fossil records
medium
medium: Omnisaura's calculation from 43 confirmed PBDB records.
Sources
Given by: Paleobiology Database. How it was chosen: PBDB leads.
Fossils found in: United States
high
high: NHM and PBDB both record it.
Canada
medium
medium: Only PBDB records it (21 records).
mixed
mixed: Levels differ between entries; each has its own.
Sources
Given by: Paleobiology Database; Natural History Museum Data Portal. How it was chosen: Union of all sources (ISO 3166).
Rock formations: Judith River Formation
high
high: NHM and PBDB both record it.
Dinosaur Park
medium
medium: Only PBDB records it (7 records).
Fruitland
medium
medium: Only PBDB records it (4 records).
Hell Creek Formation
medium
medium: Only PBDB records it (2 records).
Kirtland
medium
medium: Only PBDB records it (2 records).
Oldman
medium
medium: Only PBDB records it (2 records).
Aguja
low
low: Only one PBDB record.
mixed
mixed: Levels differ between entries; each has its own.
Sources
Given by: Paleobiology Database; Natural History Museum Data Portal. How it was chosen: Canonical names, automatic and editor-approved matches applied.
Parent group: Eupachycephalosauria
medium
medium: Only PBDB gives this; nothing contradicts it.
Sources
Given by: Paleobiology Database. How it was chosen: PBDB leads.
Order: Ornithischia
medium
medium: Only NHM gives this; nothing contradicts it.
Sources
Given by: Natural History Museum Data Portal. How it was chosen: Gap filled from NHM.
Species named in its records: Stegoceras browni, Stegoceras novomexicanum, Stegoceras validum, Stegoceras validus
Sources
Given by: Paleobiology Database (the species its fossil records are identified as).
Older or other names: Gravitholus (a junior synonym); Hanssuessia (a junior synonym); Ornatotholus (a junior synonym)
Sources
Given by: Paleobiology Database (names it treats as this genus).
Diet: herbivore (inferred for its group)
medium
medium: Only PBDB gives this, and it infers it for the whole of Ornithischia, the group this genus belongs to, not from this genus's own fossils.
Sources
Given by: Paleobiology Database. How it was chosen: PBDB, inferred from a group the genus belongs to.
Way of life: ground dwelling, gregarious (inferred for its group)
low
low: PBDB infers this way of life for the whole of Ornithischia; behaviour is rarely known for one genus.
Sources
Given by: Paleobiology Database. How it was chosen: PBDB, inferred from a group the genus belongs to.
Known from: Bones
Sources
Given by: Paleobiology Database (what the name was based on).

Sources: Paleobiology Database (CC BY 4.0), Natural History Museum Data Portal (CC0 1.0), Wikidata (CC0 1.0)Confidence levels and gaps are Omnisaura's own assessment.

Gaps are answers

What isn't known yet

Family: no source we use gives it yet.
What it was named after: no source we use gives it yet.
Held back: 3 fossil records left out: identified only tentatively (for example "cf.", "?" or the name in quotation marks).
Held back: 1 fossil record left out: identified only to a broader group, not to this genus.
Resting on one source: 6 facts come from a single source with nothing against them (rated medium): authority (PBDB); type species (PBDB); parent group (PBDB); order (NHM); common names (Wikidata); diet (PBDB).

Size and appearance aren't covered yet, and diet and way of life only as PBDB infers them for the wider group. Omnisaura leaves the rest out rather than guess.

Where sources disagree

None open. Where our sources overlap, they agree on everything shown here.

Did it meet…?

Did Stegoceras meet ?

Yes. Both are found, identified to species, in the same rocks of the same age: Dinosaur Park, Kirtland.

Going by the ages and rock formations of their dated fossils, as on the map. Compare their fossil sites on the map.

Connections

Genera linked to Stegoceras by where and when their fossils were found, by classification and by who named them. Select a name to open its page.

Same rocks, same time 86

Genera found in the same rock units, from rocks of overlapping age, the most shared fossil sites first.

Saurornitholestes Richardoestesia Triceratops Troodon Paronychodon Centrosaurus Tyrannosaurus Dromaeosaurus Edmontosaurus Thescelosaurus Corythosaurus Chirostenotes Chasmosaurus Pachycephalosaurus Lambeosaurus Gorgosaurusand 70 more

Same parent group: Eupachycephalosauria 3

Other genera in Eupachycephalosauria with a full profile.

Homalocephale Pachycephalosaurus Prenocephale

Named by Lambe 8

Genera whose naming authority includes the same surname. The authority has no initials, so different people who share a surname can appear together.

Centrosaurus Chasmosaurus Edmontosaurus Euoplocephalus Gorgosaurus Gryposaurus Panoplosaurus Styracosaurus

Found in United States 105

Other genera found in United States, from rocks of overlapping age, the most fossil sites there first.

Triceratops Tyrannosaurus Edmontosaurus Richardoestesia Paronychodon Thescelosaurus Saurornitholestes Troodon Pachycephalosaurus Alamosaurus Ornithomimus Dromaeosaurus Kritosaurus Agujaceratops Chirostenotes Parasaurolophusand 89 more

Where its fossils were found

32 fossil sites, with present-day and ancient positions

Open the map at this time

Cite this page

Omnisaura (2026). Stegoceras. Future Sailors. https://www.omnisaura.com/genera/stegoceras. Data as of 10 October 2026.

What's changed

No changes since the change log started (11 Oct 2026).

Every change to Omnisaura

Use this data

Download this genus as JSON With every source and licence attached. Also recorded in: Paleobiology Database · Wikipedia (English) · GBIF · Wikidata Spotted a problem? Tell us

Pictures

1 openly licensed picture of Stegoceras on Wikimedia Commons and museum sites, each with its own author and licence.

Stegoceras.jpg
Sebastian Bergmann from Siegburg, Germany, CC BY-SA 2.0

Credits

Where this page comes from

Paleobiology DatabaseCC BY 4.0 · fossil records, ages, classification
Natural History Museum Data PortalCC0 1.0 · catalogued specimens
WikidataCC0 1.0 · names and identifiers
OmnisauraOmnisaura editorial · confidence levels and gaps
PaleoMAP PaleoCoastlines (Kocsis and Scotese 2021)CC BY 4.0 · ancient coastlines on the small map
Natural EarthPublic domain · today's coastlines

Pictures linked from this page are credited beside each one, with their own licences; the full list is in the JSON download.