A new dinosaur shows that even Tyrannosaurus rex had humble beginnings.
Dubbed Moros intrepidus, or “the harbinger of doom,” the new species is one of the smallest tyrannosaurs yet discovered from the Cretaceous Period. Analyses of the animal’s fossilized leg show that the creature would have stood only 1.2 meters at the hip, and weighed an estimated 78 kilograms — about the size of a mule deer.
“What Moros shows is that the ancestral stock of the big tyrannosaurs was small and fast,” says Thomas Carr, a vertebrate paleontologist at Carthage College in Kenosha, Wis., who wasn’t involved in the study. And it “suggests that the tyrannosaurs became giant some time in that 16-million-year stretch between Moros and the earliest of the big guys.”
Even with the discovery of M. intrepidus, the picture of tyrannosaur evolution remains incomplete.
…[Now,] scientists need to find the rest of the skeleton of M. intrepidus as well as other tyrannosaurs in the narrow 16-million-year span between M. intrepidus and its giant descendants to help pinpoint when the creatures grew in size. “The story of tyrannosaurs is definitely not over,” [paleontologist Thomas Holtz Jr.] says.
Read full, original post: A deer-sized T. rex ancestor shows how fast tyrannosaurs became giants