By Will Dunham WASHINGTON (Reuters) -At the twilight of the age of dinosaurs, an agile and vicious predator named ...

An argument over whether fossils from several small dinosaurs represent a juvenile Tyrannosaurus rex or smaller adults of a ...

After decades of fierce debate, researchers say fossils once thought to be juvenile T. rex actually belong to a separate, ...

Specifically, whether or not certain fossils found in Montana belonged to a young Tyrannosaurus rex or a completely separate, ...

Researchers say they have uncovered a case of mistaken identity and found evidence of a species called Nanotyrannus lancensis.

Palaeontologists have argued for decades over whether certain fossils are young Tyrannosaurus rex or another species entirely ...

Fossils paleontologists initially thought belonged to a juvenile Tyrannosaurus rex actually belong to a new species of ...

A new study reveals that fossils once believed to belong to a teenage Tyrannosaurus rex may actually belong to a separate species ...

Paleontologists have long debated whether small tyrannosaurs were their own species or simply teenage T. rexes. This debate ...

The “dueling dinosaur” fossil still leaves more questions than answers as scientists now attempt to determine their causes of ...

The Nanotyrannus's small skull has been the source of debate among dinosaur experts for at least four decades, according to ...

Jane, the dinosaur fossil housed at Rockford's Burpee Museum of Natural History, may not be a Tyrannosaurus rex as previously ...