It is interesting to note that this dinosaur's name means 'different lizard'. The 'different' in 'different lizard' probably comes from its unusual vertebrae, which was much lighter than those of other dinosaurs during the time. The Allosaurus lived in the late Jurassic period, dating back to nearly 150 million years ago!

The dinosaur was named in 1877, by Othniel Marsh who pronounced the name 'al-oh-saw-rus'. The fossils were discovered in Colorado, USA. Fossils of the Allosaurus were discovered in Colorado, Montana and New Mexico. They have been unearthed in North America, Europe, Africa and even Australia.

The Allosaurus was a carnivore that ate stegosaurs and even iguanodonts that ate plants and headed the predator list. The Allosaurus was 12 m long and 10 ft in height, at the hips. It weighed between 4 and 4.5 tons! The Allosaurus was a feared predator and made quite a scary sight with its huge head and saw edge like socket set teeth. The lizard hipped dinosaur had short arms. It had hands with three fingers on each and this feature made it an advanced theropod of the age. The Allosaurus belonged to the phylum 'chordata', which implies that it had a hollow nerve chord that culminated in a brain.