Altogether, the pieces reveal a slender tyrannosaur that roamed Cretaceous Mongolia about 86 million years ago and was about 13 feet long—or about the size of juvenile T. rex that would stalk North ...

The dinosaur skeletons, found hidden in a museum collection in Mongolia, is an ancestor of the mighty tyrannosaurs.

A new species of tyrannosaur has been discovered that could change everything we thought we knew about the evolution of the ...