Saturday, 23 March 2013

Prehistoric Animals : Stegosaurus

A group of stegosaurus dinosaurs with young

Stegosaurus

Although nowhere near the largest of the Jurassic dinosaurs, Stegosaurus were still about the size of a bus. Distinctive and heavily built, they were herbivores with short forelimbs and would have walked with their small head close to the ground and the four-spiked tail held high. The double row of plates running along the back helped control body temperature and were probably used in display or possibly in defence against carnivorous Allosaurs. Most fossils for the three known species, including some complete skeletons, have come from the USA, although a recent discovery in Portugal suggests a wider distribution.
Scientific name: Stegosaurus
Rank: Genus
roof-lizard

Stegosaurus (pron.: /ˌstɛɡɵˈsɔrəs/, meaning "roof lizard" or "covered lizard" in reference to its bony plates) is a genus of armored stegosaurid dinosaur. They lived during the Late Jurassic period (Kimmeridgian to early Tithonian), some 155 to 150 million years ago in what is now western North America. In 2006, a specimen of Stegosaurus was announced from Portugal, showing that they were present in Europe as well. Due to its distinctive tail spikes and plates, Stegosaurus is one of the most recognizable dinosaurs. At least three species have been identified in the upper Morrison Formation and are known from the remains of about 80 individuals.
A large, heavily built, herbivorous quadruped, Stegosaurus had a distinctive and unusual posture, with a heavily rounded back, short forelimbs, head held low to the ground and a stiffened tail held high in the air. Its array of plates and spikes has been the subject of much speculation. The spikes were most likely used for defense, while the plates have also been proposed as a defensive mechanism, as well as having display and thermoregulatory functions. Stegosaurus had a relatively low brain-to-body mass ratio. It had a short neck and small head, meaning it most likely ate low-lying bushes and shrubs. It was the largest of all the stegosaurians (bigger than genera such as Kentrosaurus and Huayangosaurus) and, although roughly bus-sized, it nonetheless shared many anatomical features (including the tail spines and plates) with the other stegosaurian genera.