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

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How sure are we?2 high12 medium11 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 11 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
medium
medium: 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.
medium
medium: 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
medium
medium: 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
medium
medium: Only PBDB gives a range this precise; NHM's records give only a broader interval, which contains it.
Omnisaura calculation143.1–119.6 million years ago, from its dated fossil records
medium
medium: Omnisaura's calculation from 13 confirmed PBDB records.
Sources
Given by: Paleobiology Database. How it was chosen: PBDB leads.
Fossils found in: United Kingdom
high
high: NHM and PBDB both record it.
Spain
medium
medium: Only PBDB records it (3 records).
Belgium
low
low: Only one PBDB record.
France
low
low: Only one PBDB record.
Portugal
low
low: Only one PBDB record.
Romania
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: Union of all sources (ISO 3166).
Rock formations: Weald Clay Formation
high
high: NHM and PBDB both record it.
Arcillas de Morella
medium
medium: Only PBDB records it (2 records).
Wessex Formation
medium
medium: Only PBDB records it (3 records).
Calcaires à Spatangues
low
low: Only one PBDB record.
Hythe
low
low: Only one PBDB record.
Lower Bauxite
low
low: Only one PBDB record.
Papo Seco
low
low: Only one PBDB record.
Sainte-Barbe Clays
low
low: Only one PBDB record.
Vectis Formation
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: Iguanodontia
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.
Named after: Gideon Mantell
medium
medium: Only Wikidata gives this; nothing contradicts it.
Sources
Given by: Wikidata. How it was chosen: Wikidata leads.
Species named in its records: Mantellisaurus atherfieldensis
Sources
Given by: Paleobiology Database (the species its fossil records are identified as).
Older or other names: Dollodon (a junior synonym); Mantellodon (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 Ornithopoda, 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.
Common names: no source we use gives it yet.
Held back: 4 fossil records left out: identified only tentatively (for example "cf.", "?" or the name in quotation marks).
Resting on one source: 7 facts come from a single source with nothing against them (rated medium): authority (PBDB); type species (PBDB); parent group (PBDB); order (NHM); age (headline) (PBDB); named after (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 Mantellisaurus 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.

Connections

Genera linked to Mantellisaurus 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 15

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

Iguanodon Polacanthus Valdosaurus Baryonyx Cetiosaurus Hypsilophodon Ornithopsis Brighstoneus Cariocecus Ceratosuchops Comptonatus Erectopus Hylaeosaurus Megalosaurus Owenodon

Same parent group: Iguanodontia 2

Other genera in Iguanodontia with a full profile.

Choyrodon Osmakasaurus

Named by Paul 2

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

Dakotadon Giraffatitan

Found in United Kingdom 15

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

Iguanodon Polacanthus Cetiosaurus Ornithopsis Valdosaurus Hypsilophodon Baryonyx Hylaeosaurus Megalosaurus Aristosuchus Brighstoneus Calamosaurus Ceratosuchops Comptonatus Pelorosaurus

Where its fossils were found

13 fossil sites, with present-day and ancient positions

Open the map at this time

Cite this page

Omnisaura (2026). Mantellisaurus. Future Sailors. https://www.omnisaura.com/genera/mantellisaurus. Data as of 11 October 2026.

What's changed

19 Oct 2026
Age (PBDB): confidence high → medium.

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

183 openly licensed pictures of Mantellisaurus on Wikimedia Commons and museum sites, each with its own author and licence.

Mantellisaurus atherfieldensis Steveoc.jpg
Steveoc 86, CC BY-SA 3.0
NHM-UK_P_DF118_03_03_0185
The Trustees of the Natural History Museum, London, CC BY 4.0
NHM-UK_P_DF118_03_05_0031
The Trustees of the Natural History Museum, London, CC BY 4.0
NHM-UK_P_DF118_03_24_0425
The Trustees of the Natural History Museum, London, CC BY 4.0

The rest are listed in the JSON download.

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.