Nanotyrannus and Tyrannosaurus coexisted at the close of the Cretaceous
Nanotyrannus is a distinct genus outside Tyrannosauridae containing two species, N. lancensis and N. lethaeus, confirmed by the mature specimen NCSM 40000.
Scientists thought this fossil was a teen T. rex. Turns out it's a new tyrannosaur
The "Dueling Dinosaurs" find indicates multiple tyrannosaur species, including Nanotyrannus, coexisted with T. rex, overturning assumptions of T. rex as sole top predator.
