Dinosaur Vault / Field fact sheet
Metriacanthosaurus
Metriacanthosaurus parkeri / "moderately spined lizard"
Say it: met-ree-a-kan-tho-sore-us
- When
- Late Jurassic
- Where
- Dorset, England
- Diet
- Meat eater
- Length estimate
- About 8.2 m (27 ft)
Length is reconstructed from incomplete remains. The skull, hands and skin covering are unknown.
From the specimen
What was actually found?
The name Metriacanthosaurus parkeri is anchored to a holotype, the reference specimen for the species. The partial skeleton, OUMNH J.12144, is held at Oxford University Museum of Natural History. It includes vertebrae, pelvic bones and hindlimb bones, rather than a complete skeleton with a skull. Oxford specimen record
The Oxford specimen record places a tail vertebra from that skeleton at Jordan Cliff, Overcombe, near Weymouth in Dorset. Research identifies the rocks as the Weymouth Member of the Oxford Clay. The bones were first assigned to Megalosaurus; Walker established Metriacanthosaurus as a separate genus in 1964. That is a naming date, not a discovery date. Research review, pp. 495, 502
How does it compare?
All three were large meat-eating theropods. Family relationships and the completeness of their fossils are more useful comparisons than a precise size ranking.
Allosaurus
An allosaurid from the Late Jurassic, especially well known from North America. Its skull preserves distinctive horns above the eyes. Metriacanthosaurus belongs to a different family, Metriacanthosauridae, and its missing skull cannot show whether it had similar ornaments.
Yangchuanosaurus
A fellow metriacanthosaurid from China. Nearly complete specimens of Yangchuanosaurus shangyouensis give a much fuller picture of its anatomy. These fossils help with comparisons, but do not establish the exact shape of the missing parts of Metriacanthosaurus.
Sources: Natural History Museum: Allosaurus; Zou and colleagues, 2025. Relationships within the family remain under study; similarity does not make these animals the same genus.
Think like a paleontologist
Why would finding a skull change how we reconstruct this dinosaur?