Researchers discover new tyrannosaur species in ‘duelling dinosaurs’ fossil

Analysis of Montana fossils shows the battling predator was a fully grown Nanotyrannus, not a young T rex

The fossilised remains of two dinosaurs locked in combat have unleashed a fresh drama, suggesting diminutive specimens thought to be Tyrannosaurus rex teenagers could instead be separate, smaller species.

The duelling dinosaurs" fossil, which reveals a triceratops in battle with a medium-sized tyrannosaur, was unearthed in Montana by commercial fossil hunters in 2006 and dates to shortly before the asteroid strike that ended the reign of the dinosaurs 66m years ago.