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

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How sure are we?3 high7 medium9 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

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
medium
medium: 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.
medium
medium: 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
medium
medium: Only PBDB gives a range this precise; NHM's records give only a broader interval, which contains it.
Omnisaura calculation139.1–100.5 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).
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: Wessex Formation
high
high: NHM and PBDB both record it.
Arcillas de Morella
low
low: Only one PBDB record.
Ferruginous Sands
low
low: Only one PBDB record.
Golmayo
low
low: Only one PBDB record.
Piedrahita de Muñó
low
low: Only one PBDB record.
Tunbridge Wells Sand Formation
low
low: Only one PBDB record.
Upper Greensand Formation
disputed
low: Only NHM gives this name and it matches no PBDB formation; awaiting an editor.
Vectis Formation
low
low: Only one PBDB record.
Wadhurst Clay 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.
Family: Nodosauridae
high
high: PBDB and NHM agree.
Sources
Given by: Paleobiology Database; Natural History Museum Data Portal. How it was chosen: PBDB leads.
Parent group: Nodosauridae
medium
medium: Only PBDB gives this; nothing contradicts it.
Sources
Given by: Paleobiology Database. How it was chosen: PBDB leads.
Species named in its records: Polacanthus becklesi, Polacanthus foxi, Polacanthus foxii, Polacanthus rudgwickensis
Sources
Given by: Paleobiology Database (the species its fossil records are identified as).
Older or other names: Euacanthus (a junior synonym); Vectensia (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

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 the name in quotation marks).
Held back: 4 fossil records left out: identified only to a broader group, not to this genus.
Resting on one source: 4 facts come from a single source with nothing against them (rated medium): authority (PBDB); parent group (PBDB); age (headline) (PBDB); 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

1 open

Formations

records nothing herePBDB
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…?

Did Polacanthus 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.

Connections

Genera linked to Polacanthus 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 Valdosaurus Hypselospinus Mantellisaurus Cetiosaurus Barilium Hylaeosaurus Megalosaurus Hypsilophodon Ornithopsis Baryonyx Brighstoneus Ceratosuchops Comptonatus Pelorosaurus

Same family: Nodosauridae 17

Other genera in Nodosauridae with a full profile.

Acantholipan Animantarx Anoplosaurus Borealopelta Edmontonia Gastonia Glyptodontopelta Hoplitosaurus Hungarosaurus Hylaeosaurus Niobrarasaurus Nodosaurus Panoplosaurus Sauropelta Silvisaurus Struthiosaurusand 1 more

Found in United Kingdom 20

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

Iguanodon Hylaeosaurus Hypselospinus Megalosaurus Valdosaurus Mantellisaurus Cetiosaurus Ornithopsis Barilium Hypsilophodon Baryonyx Iguanodontipus Aristosuchus Brighstoneus Calamosaurus Ceratosuchopsand 4 more

Where its fossils were found

12 fossil sites, with present-day and ancient positions

Open the map at this time

Cite this page

Omnisaura (2026). Polacanthus. Future Sailors. https://www.omnisaura.com/genera/polacanthus. Data as of 10 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

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

Polacanthus Pelvis.jpg
Carpenter, Kenneth, CC BY-SA 4.0
Polacanthus foxii.jpg
FunkMonk, hip armour by Franz Nopcsa von Felső-SzilvásFile:Polacanthus skeleton.jpg, CC BY-SA 3.0
Polcanthus material.jpg
Carpenter, Kenneth, CC BY-SA 4.0
NHM-UK_P_DF118_03_04_0421
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.