Dinosaur genus

Monoclonius

Cope 1876

Monoclonius is a dinosaur genus known from bones, found in rocks 83.6–72.2 million years old, in Canada and the United States.

Also calledja モノクロニウス

medium

medium: Only Wikidata gives this; nothing contradicts it.

Confidence labels

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How sure are we?3 high10 medium1 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 12 October 2026

83.6–72.2 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: Cope 1876
medium
medium: Only PBDB gives this; nothing contradicts it.
Sources
Given by: Paleobiology Database. How it was chosen: PBDB leads.
Described in: E. D. Cope (1876). Descriptions of some vertebrate remains from the Fort Union Beds of Montana. Proceedings of the Academy of Natural Sciences of Philadelphia 28: 248–261.
medium
medium: Only PBDB gives this; its author and year match the naming authority (Cope 1876).
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: Monoclonius crassus
medium
medium: Only PBDB gives this; nothing contradicts it.
Sources
Given by: Paleobiology Database. How it was chosen: PBDB leads.
Lived: Campanian, 83.6–72.2 million years ago
high
high: PBDB and NHM agree.
Omnisaura calculation83.6–72.2 million years ago, from its dated fossil records
medium
medium: Omnisaura's calculation from 10 confirmed PBDB records.
Sources
Given by: Paleobiology Database. How it was chosen: PBDB leads.
Fossils found in: Canada
high
high: NHM and PBDB both record it.
United States
medium
medium: Only PBDB records it (4 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
medium
medium: Only PBDB records it (3 records).
Oldman
medium
medium: Only PBDB records it (5 records).
Kirtland
low
low: Only one PBDB record.
mixed
mixed: Levels differ between entries; each has its own.
Sources
Given by: Paleobiology Database. How it was chosen: Canonical names, automatic and editor-approved matches applied.
Family: Ceratopsidae
high
high: PBDB and NHM agree.
Sources
Given by: Paleobiology Database; Natural History Museum Data Portal. How it was chosen: PBDB leads.
Parent group: Centrosaurinae
medium
medium: Only PBDB gives this; nothing contradicts it.
Sources
Given by: Paleobiology Database. How it was chosen: PBDB leads.
Order: Dinosauria
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.
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

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 "?").
Held back: 1 fossil record left out: identified as a related genus rather than this one.
Resting on one source: 5 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).

Size, diet and behaviour aren't covered yet. Omnisaura leaves them out rather than guess.

Where sources disagree

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

Did it meet…?

Did Monoclonius meet ?

Possibly. Both are recorded from the same rocks of the same age (Kirtland), but there one of them is identified only to genus (for example from an isolated tooth).

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

Lived alongside

Genera found in the same rock formations, from rocks of the same age.

Saurornitholestes Troodon Richardoestesia Paronychodon Stegoceras Dromaeosaurus Daspletosaurus Parasaurolophus Centrosaurus Kritosaurus Brachylophosaurus Stenonychosaurus Struthiomimus Albertosaurus Corythosaurus Pentaceratopsand 43 more

Same family

Other genera in Ceratopsidae with a full profile.

Achelousaurus Agujaceratops Albertaceratops Anchiceratops Arrhinoceratops Avaceratops Bisticeratops Bravoceratops Centrosaurus Ceratopsipes Chasmosaurus Coahuilaceratops Coronosaurus Crittendenceratops Diabloceratops Einiosaurusand 9 more

Where its fossils were found

8 fossil sites, with present-day and ancient positions

Open the map at this time

Cite this page

Omnisaura (2026). Monoclonius. Future Sailors. https://www.omnisaura.com/genera/monoclonius. Data as of 12 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. Spotted a problem? Tell us

Pictures

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

NHM-UK_P_DF118_03_22_0341
The Trustees of the Natural History Museum, London, CC BY 4.0

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.