In the last few years many new examples of the tyrannosaur family have been discovered. Detailed research on these and the more well known T rex have allowed scientists to build up a detailed picture of this most famous of all dinosaur evolution. For most of the tyrannosaur evolutionary family tree they were small creatures, it was not until the last 20 million years at the very end of the Cretaceous period that they evolved into the large T rex species.

T rex was first scientifically named and described in 1905, and is the most famous and iconic of all dinosaurs. It was a fierce predator weighing in at about 7 tonnes. However the earliest ancestors of this dinosaur were small raptor like dinosaurs living some 165 million years ago during the Jurassic period.