For decades, scientists have been counting annual growth rings—similar to tree rings—inside fossilized leg bones of ...

A new analysis of fossils believed to be juveniles of T. rex now shows they were adults of a small tyrannosaur, with narrower jaws, longer legs, and bigger arms than T. rex. The species, Nanotyrannus ...

A fossilized partial dinosaur skull originally thought to be from a Tyrannosaurus rex might actually represent a previously unknown species, according to a paper published Thursday in the journal ...