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Temporal range: Lower Jurassic
196.5–183 mya
Scelidosaurus harrisonii (1).jpg
Scelidosaurus cast of the David Sole specimen, in Utah.
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: Ornithischia
Clade: Thyreophora
Clade: Thyreophoroidea
Family: Scelidosauridae
Genus: Scelidosaurus
Owen, 1859
S. harrisonii
Binomial name
Scelidosaurus harrisonii
Owen, 1861

Scelidosaurus was an early type of herbivorous dinosaur. It was a thyreophoran, a lightly plated, herbivorous dinosaur about 4 metres long. It lived during the early Jurassic, 208 to 194 million years ago. Its fossils have been found in England, Ireland,[1] and in Arizona, in the United States.

Scelidosaurus has been called the earliest complete dinosaur.[2] This and related genera have been found on three continents.

It is one of the earliest and most basal of the armoured dinosaurs. A review by Serano had Scelidosaurus as the sister group (closest relative) to both the Stegosauria and Ankylosauria.[3]

A full-grown Scelidosaurus was rather small, compared to some later dinosaurs. Its length was about 4 metres (13 ft).[4] Scelidosaurus was quadrupedal, with the hindlimbs longer than the forelimbs. It may have reared up on its hind legs to browse on foliage from trees, but its forefeet were as large as its hind feet, indicating a mostly quadrupedal posture.

Scelidosaurus and its Jurassic relatives were herbivorous. Other ornithischians had teeth capable of grinding plant material, but Scelidosaurus had smaller, less complex teeth. Its jaw could only do simple up-and-down movements.[4] In this aspect, they resembled the stegosaurids, which also had primitive teeth and simple jaws.[5] Also, like stegosaurs, they may have swallowed gastroliths to aid processing of food (because of the lack of chewing ability). This is also done by modern birds and crocodiles.[6] The diet of Scelidosaurus was low-lying plants (like cycads) and probably also fruits.[4] Seaweeds have also been suggested as its food. Grass did not evolve until the Cretaceous period.

References[change | change source]

  1. BBC Family & Education. [1]
  2. Norman, David 2001. Scelidosaurus, the earliest complete dinosaur. In The armored dinosaurs, pp 3-24. Bloomington: Indiana University Press. ISBN 0253339642
  3. Serano P.C. 1986. Phylogeny of the bird-hipped dinosaurs (Order Ornithischia). National Geographic Research 2, 234–256.
  4. 4.0 4.1 4.2 Lambert D 1993. The ultimate dinosaur book. Dorling Kindersley, New York, p110-113. ISBN 1-56458-304-X
  5. Galton PM, Upchurch P (2004). "Stegosauria". In Weishampel DB, Dodson P, Osmólska H (ed.). The Dinosauria (2nd Edition. University of California Press. p. 361. ISBN 0-520-24209-2.CS1 maint: multiple names: editors list (link)
  6. Stegosaurs Jacobson RJ. Dinosaur and vertebrate paleontology information. Retrieved 2007-02-11.