Answer to fossil record puzzle may lie with teenage T rexes, study finds

Absence of smaller dinosaurs may be result of adolescent megatheropods crowding them out

Teenage T rexes and other carnivorous dinosaurs the size of lions or bears may have crowded out smaller species, explaining why there are so few of them preserved in the fossil record, research suggests.

Despite dominating the land for more than 150 million years, dinosaurs were not particularly diverse, and most known species were giants weighing 1,000kg or more - including massive, meat-eating megatheropods such as Tyrannosaurus rex.