Take a look at Allosaurus jimmadseni, an 8- to 9-meter-long (26- to 29-foot), 4,000-pound carnivore that lived in North America between 157 million and 152 million years ago.

An artist's illustration of Allosaurus jimmadseni, a newly described species of Jurassic carnivore Andrey Atuchin. About about 145 million to 200 million years ago d uring the Jurassic Period ...

In middle-of-nowhere Utah, there is a piece of earth more dense with theropod dinosaur bones from the Jurassic period than anywhere else, populated mostly by a predator called Allosaurus that ...