Stegoceras

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For the stegosaur of a similar name, see Stegosaurus.

Stegoceras

Extinct (fossil)

Scientific classification

Kingdom:	Animalia
Phylum:	Chordata
Class:	Sauropsida
Superorder:	Dinosauria
Order:	Ornithischia
Suborder:	Marginocephalia
Infraorder:	Pachycephalosauria
Family:	Pachycephalosauridae
Genus:	Stegoceras Lambe, 1902

Species

S. validum Lambe, 1902

Stegoceras (named for its 'horned roof' - Greek stego-/στεγο- meaning 'roof' and ceras/κέρας meaning 'horn') was a plant-eating ornithischian pachycephalosaurid dinosaur that lived in what is now North America during the Late Cretaceous Period. It had an estimated length of up to 2 metres (6.5 feet). It was named by Lawrence Lambe, in 1902.

It is often used as a model for the reconstruction of other pachysephalosaurs because there are other recovered parts of this dinosaur, as opposed to just the skull. When it was first recovered, it was thought to be related to and often considered to be Troodon. This theory was, however, dispelled, when a skull was found, which was quite distinct from that of Troodon.

[edit] Anatomy

Stegoceras had a skull which measured 3 inches in thickness. Although it is uncertain, it has been proposed by Peter Galton in 1971 that the skull dome, of both Stegoceras and Pachycephalosauria, was used for fighting for mates between males. It was later theorised that they where for attacking predators because if two Stegoceras participated in a headbutting match (perhaps for mating purposes, or in order to determine an alpha male) it would be very easy for the dome shaped skull to slip and ram the opponent in the neck if not perfectly aligned.

Stegoceras portrayed Head Butting

Despite this, there are features which would support the theory of headbutting amongst this species, such as the short neck with muscles that hold the head at right angles to the neck so the dome faces forward when the head is lowered, and strong back (this can particularly be seen in the stiffness of the creature's tail) which would be more than capable of sustaining impact via the skull and muscular legs which could perhaps take the shock from the blow and help the dinosaur hold its ground. Also the growth patterns of the bone cells, which grow in the direction of greatest stress, suggest that the skull was subject to great outside pressures.^[1]

Scars have not been found, however, to support this theory and it is in doubt whether the skull itself (and brain) could have withstood this impact, owing to lack of air spaces within the skull to absorb shock. Which is why its been proposed by Bob Bakker that they butted each other in the flank and chest rather than the head.^[2]

[edit] See also

Pachycephalosaurus

[edit] References

Sues, H.-D., and P. M. Galton. 1987. Anatomy and classification of the North American Pachycephalosauria (Dinosauria: Ornithischia). Palaeontographica Abteilung A 198: 1–40.

Fantastic Facts About Dinosaurs (ISBN 0-7525-3166-2)
Cranfield, I. (2004). The Illustrated Directory of Dinosaurs and other Prehistoric Creatures (pp 228-233) - Greenwich Editions - ISBN 0-86288-662-7