Cetiosaurus oxoniensis
Cetiosaurus oxoniensis was a medium-sized sauropod with a barrel-shaped body, four pillar-like limbs, a long but relatively stiff neck and a long tapering tail that was carried clear of the ground rather than dragged. It reached roughly 14–18 metres in length and is usually estimated at 9–15 tonnes, making it considerably smaller than giants such as Brachiosaurus.
Cetiosaurus
Cetiosaurus oxoniensis
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Weight
9000–15000 kg
Length
14–18 m
Diet
Herbivore
Period
Jurassic
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9000–15000 kg
14–18 m
Jurassic
Quadrupedal
3.5–4.5 m
15 km/h
Herbivore
6 recorded fossil finds in United Kingdom. First described in 1871 by Phillips.
Sites and counts from the Paleobiology Database
The timeline shows the whole age of dinosaurs – and how much time has passed since. The glowing part is when Cetiosaurus lived.
million years ago
Lived 168.3–166.1 million years ago
If the whole age of dinosaurs were a single day, Cetiosaurus lived at 10:56.
Chapter • Meet the dinosaur
Cetiosaurus oxoniensis was a medium-sized sauropod with a barrel-shaped body, four pillar-like limbs, a long but relatively stiff neck and a long tapering tail that was carried clear of the ground rather than dragged. It reached roughly 14–18 metres in length and is usually estimated at 9–15 tonnes, making it considerably smaller than giants such as Brachiosaurus. The head was small relative to the body and the jaws carried broad, spoon-shaped teeth. Its vertebrae are strikingly solid and only partly hollowed by air spaces, a comparatively primitive condition next to later sauropods like Diplodocus, whose skeletons were far more pneumatic and lightly built. The body was covered in scaly skin; there is no evidence of feathers or feather-like structures in sauropods. Like all sauropods, Cetiosaurus moved on four legs in a fully horizontal posture, with the hips and shoulders supporting neck and tail like the towers of a bridge. Its forelimbs were relatively long compared with the hindlimbs, so the back sloped gently upwards towards the hips. An animal of this bulk was no sprinter: comparisons with sauropod trackways suggest a normal walking speed of just a few kilometres per hour and a top speed unlikely to exceed about 15 km/h. The long neck gave reach rather than great height, letting the animal sweep across a wide feeding area without shifting its heavy body. Cetiosaurus was a plant eater, browsing on conifer foliage, ginkgo leaves, ferns, horsetails and cycads — grasses had not yet spread across the world. Its teeth were built for stripping and nipping vegetation rather than chewing, so food was swallowed largely whole and broken down slowly in an enormous fermenting gut with the help of microbes. Given its body mass, the animal must have consumed several hundred kilograms of plant matter every day. Cetiosaurus holds a special place in the history of palaeontology. Richard Owen coined the name in 1841 — it means "whale lizard" — for a set of huge vertebrae and bone fragments from England, which he initially interpreted as belonging to a gigantic marine reptile, perhaps a colossal crocodile. The species C. oxoniensis was described in 1871 by John Phillips on the basis of far more complete material quarried at Bletchingdon Station in Oxfordshire. Another famous find is the "Rutland Dinosaur", a partial skeleton unearthed in 1968 in a quarry near Great Casterton, Rutland, now on display in a museum in Leicester. Because Owen's original type material was so poor, the International Commission on Zoological Nomenclature formally ruled in 2014 that C. oxoniensis should serve as the type species of the genus.
Chapter • Where it lived
Cetiosaurus lived about 168–166 million years ago, during the Bathonian stage of the Middle Jurassic. What is now England was then an archipelago of low islands and coastal plains set in a warm, shallow sea. The animal probably browsed on floodplains, in near-coastal forests of conifers, cycads and ginkgoes, and along river mouths. Its fossils come from the United Kingdom, chiefly from quarries in Oxfordshire (including Bletchingdon Station) and from Rutland (Great Casterton), where the bones occur in marine and near-shore limestones and clays. The presence of land-dwelling dinosaurs in marine deposits indicates that carcasses drifted out to sea before burial. The Ardley quarry in Oxfordshire also preserves long sauropod trackways of the same age that may well have been made by animals of the Cetiosaurus type.
Chapter • Wild behavior
Cathemeral
No bonebeds containing several individuals of Cetiosaurus are known, so its social life remains uncertain. However, long and partly parallel sauropod trackways of the same age occur at Ardley quarry in Oxfordshire, which may indicate that sauropods moved in groups. The inference is indirect: the tracks cannot be tied with certainty to Cetiosaurus itself, and parallel trackways can also form when separate animals follow the same shoreline at different times.
The name Cetiosaurus means "whale lizard": in 1841 Richard Owen thought the bones came from an enormous sea-going reptile, not a dinosaur.
Cetiosaurus was one of the very first sauropods ever to receive a scientific name.
The species name oxoniensis refers to Oxford, because the best material came from quarries in Oxfordshire.
The "Rutland Dinosaur", found in 1968, is one of Britain's most complete sauropod skeletons and is displayed at the New Walk Museum in Leicester.
Its back vertebrae are unusually massive for a sauropod, lacking the deep air pockets that made the skeleton of Diplodocus so light.
In 2014 the International Commission on Zoological Nomenclature had to step in and formally designate C. oxoniensis as the type species, because Owen's original bones were too fragmentary.
Cetiosaurus lived in the Middle Jurassic, when much of what is now England lay beneath warm, shallow seas dotted with islands.
Many of its bones were found in marine limestones, suggesting carcasses were washed out from land and sank to the sea floor.
Chapter • Scientific place
Journal of Vertebrate Paleontology (Taylor & Francis)
Reviewed: 9/6/2026
Upchurch & Martin's (2003) revision establishes the saurischian–sauropodomorph–eusauropod placement of Cetiosaurus and shows that C. oxoniensis is the only valid, diagnosable species of the genus.
Open sourcePalaeontology (Wiley, for the Palaeontological Association)
Reviewed: 9/6/2026
Documents the geographic and stratigraphic occurrence of Cetiosaurus oxoniensis in the Middle Jurassic of Rutland, United Kingdom, alongside the Oxfordshire material.
Open sourcePalaeontology (Wiley, for the Palaeontological Association)
Reviewed: 9/6/2026
Describes the Bathonian Ardley Quarry track-bearing carbonate horizon in Oxfordshire with over 40 sauropod and theropod trackways, documenting the shallow-marine/near-coastal palaeoenvironment inhabited by Cetiosaurus-type sauropods.
Open sourceCambridge University Press
Reviewed: 9/6/2026
Peer-reviewed synthesis of sauropod dentition and cranial function establishing that eusauropods such as Cetiosaurus were bulk plant-eating herbivores.
Open sourcePaleobiology Database
Reviewed: 9/6/2026
Extinct taxon; conservation status NE
Open sourceNatural History Museum, London
Reviewed: 9/6/2026
Museum overview of Cetiosaurus covering its size, body plan, plant-eating habits and Middle Jurassic British occurrence, used as the general reference for the sv, en, da and no description texts.
Open sourceNatural History Museum, London
Reviewed: 9/6/2026
Museum overview of Cetiosaurus covering its size, body plan, plant-eating habits and Middle Jurassic British occurrence, used as the general reference for the sv, en, da and no description texts.
Open sourceNatural History Museum, London
Reviewed: 9/6/2026
Museum overview of Cetiosaurus covering its size, body plan, plant-eating habits and Middle Jurassic British occurrence, used as the general reference for the sv, en, da and no description texts.
Open sourceNatural History Museum, London
Reviewed: 9/6/2026
Museum overview of Cetiosaurus covering its size, body plan, plant-eating habits and Middle Jurassic British occurrence, used as the general reference for the sv, en, da and no description texts.
Open source