Allosaurus

Allosaurus (pronounced /ˌælɵˈsɔrəs/) is a genus of large theropod dinosaur that lived 155 to 145 million years ago, in the late Jurassic period (Kimmeridgian to Tithonian). The name Allosaurus means "different lizard" and is derived from the Greek αλλος/allos ("different, strange") and σαυρος/sauros ("lizard").

 

 

Allosaurus was a large bipedal predator with a large skull, equipped with dozens of large, sharp teeth. It averaged 8.5 meters (28 ft) in length, though fragmentary remains suggest it could have reached over 12 meters (39 ft). Relative to the large and powerful hindlimbs, its three-fingered forelimbs were small, and the body was balanced by a long, heavy tail.

 

The different species of Allosaurus varied in weight. Allosaurus fragilis, A. atrox, and A. ferox weighed about 1.1 to 1.9 tons (1 tonne to 1.7 tonnes); A. amplexus was much heavier and weighed about 2.7 to 5.5 tons (3 tonnes to 5 tonnes).

Look at this beautiful video from Walking with Dinosaurs - Diplodocus Hunting (allosaurs in action)