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Dinosaur genus

Polacanthus

Fox 1866

Polacanthus is a dinosaur genus known from bones, found in rocks 139.1–100.5 million years old, in the United Kingdom and Spain.

Confidence labels
How sure are we?4 high5 medium8 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
139.1–100.5 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
Fox 1866
mediummedium: Only PBDB gives this; nothing contradicts it.
Sources

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

Described in
W. Fox (1866). On a new Wealden saurian named Polacanthus. Report of the British Association for the Advancement of Science, Birmingham 1865: 56.
mediummedium: Only PBDB gives this; its author and year match the naming authority (Fox 1866).
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.

Lived
Berriasian to Albian, 139.1–100.5 million years ago
highhigh: PBDB and NHM agree.
Omnisaura calculation139.1–100.5 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).
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
Wessex Formation
highhigh: NHM and PBDB both record it.
Arcillas de Morella
lowlow: Only one PBDB record.
Ferruginous Sands
lowlow: Only one PBDB record.
Golmayo
lowlow: Only one PBDB record.
Piedrahita de Muñó
lowlow: Only one PBDB record.
Tunbridge Wells Sand Formation
lowlow: Only one PBDB record.
Upper Greensand Formation
disputedlow: Only NHM gives this name and it matches no PBDB formation; awaiting an editor.
Vectis Formation
lowlow: Only one PBDB record.
Wadhurst Clay 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.

Family
Nodosauridae
highhigh: PBDB and NHM agree.
Sources

Given by: Paleobiology Database; Natural History Museum Data Portal. How it was chosen: PBDB leads.

Parent group
Nodosauridae
mediummedium: Only PBDB gives this; nothing contradicts it.
Sources

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

  • Type species: no source we use gives it yet.
  • Order: no source we use gives it yet.
  • Common names: 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 "?").
  • Held back: 4 fossil records left out: identified only to a broader group, not to this genus.
  • Resting on one source: 2 facts come from a single source with nothing against them (rated medium): authority (PBDB); parent group (PBDB).

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

Where sources disagree

1 open

Formations

  • NonePBDB
  • Upper Greensand FormationNHM

One source names a formation the other does not. An editor hasn't ruled yet, so this is rated low until they do.

Did it meet…?

?

No. Polacanthus had gone at least 16.9 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.

IguanodonValdosaurusHypselospinusMantellisaurusCetiosaurusMegalosaurusBariliumHylaeosaurusHypsilophodonOrnithopsisBaryonyxBrighstoneusCeratosuchopsComptonatusPelorosaurus

Same family

Other genera in Nodosauridae with a full profile.

AcantholipanAnimantarxAnoplosaurusBorealopeltaEdmontoniaGastoniaGlyptodontopeltaHoplitosaurusHungarosaurusHylaeosaurusNiobrarasaurusNodosaurusPanoplosaurusSauropeltaSilvisaurusStruthiosaurusand 1 more

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.