Omnisaura
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Dinosaur genus

Mantellisaurus

Paul 2007

Mantellisaurus is a dinosaur genus known from bones, found in rocks 143.1–119.6 million years old, in 6 countries, most often the United Kingdom and Spain.

Confidence labels
How sure are we?3 high10 medium10 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
143.1–119.6 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
Paul 2007
mediummedium: Only PBDB gives this; nothing contradicts it.
Sources

Given by: Paleobiology Database. How it was chosen: PBDB leads.

Described in
G. S. Paul (2007). Turning the old into the new: a separate genus for the gracile iguanodont from the Wealden of England. Horns and Beaks: Ceratopsian and Ornithopod Dinosaurs: 69–77.
mediummedium: Only PBDB gives this; its author and year match the naming authority (Paul 2007).
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
Mantellisaurus atherfieldensis
mediummedium: Only PBDB gives this; nothing contradicts it.
Sources

Given by: Paleobiology Database. How it was chosen: PBDB leads.

Lived
Berriasian to Aptian, 143.1–119.6 million years ago
highhigh: PBDB and NHM agree.
Omnisaura calculation143.1–119.6 million years ago, from its dated fossil records
mediummedium: Omnisaura's calculation from 13 confirmed PBDB records.
Sources

Given by: Paleobiology Database. How it was chosen: PBDB leads.

Fossils found in
United Kingdom
highhigh: NHM and PBDB both record it.
Spain
mediummedium: Only PBDB records it (3 records).
Belgium
lowlow: Only one PBDB record.
France
lowlow: Only one PBDB record.
Portugal
lowlow: Only one PBDB record.
Romania
lowlow: Only one PBDB record.
mixedmixed: 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
Weald Clay Formation
highhigh: NHM and PBDB both record it.
Arcillas de Morella
mediummedium: Only PBDB records it (2 records).
Wessex Formation
mediummedium: Only PBDB records it (3 records).
Calcaires à Spatangues
lowlow: Only one PBDB record.
Hythe
lowlow: Only one PBDB record.
Lower Bauxite
lowlow: Only one PBDB record.
Papo Seco
lowlow: Only one PBDB record.
Sainte-Barbe Clays
lowlow: Only one PBDB record.
Vectis Formation
lowlow: Only one PBDB record.
mixedmixed: 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
Iguanodontia
mediummedium: Only PBDB gives this; nothing contradicts it.
Sources

Given by: Paleobiology Database. How it was chosen: PBDB leads.

Order
Ornithischia
mediummedium: Only NHM gives this; nothing contradicts it.
Sources

Given by: Natural History Museum Data Portal. How it was chosen: Gap filled from NHM.

Named after
Gideon Mantell
mediummedium: Only Wikidata gives this; nothing contradicts it.
Sources

Given by: Wikidata. How it was chosen: Wikidata leads.

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.
  • Common names: no source we use gives it yet.
  • Held back: 4 fossil records left out: identified only tentatively (for example "cf." or "?").
  • 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); named after (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…?

?

No. Mantellisaurus had gone at least 36 million years before Tyrannosaurus appears in the fossil record.

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.

IguanodonPolacanthusValdosaurusBaryonyxCetiosaurusHypsilophodonOrnithopsisBrighstoneusCariocecusCeratosuchopsComptonatusErectopusHylaeosaurusMegalosaurusOwenodon

Same parent group

Other genera in Iguanodontia with a full profile.

ChoyrodonOsmakasaurus

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.