Washington: Scientists have discovered a new species of tiny tyrannosaur which helps explain how the dinosaurs evolved from small, speedy hunters, into the bone-crushing apex predators that we know. The species called Moros intrepidus is a small tyrannosaur who lived about 96 million years ago in the lush, deltaic environment of what is now Utah during the Cretaceous period.
The tyrannosaur, described in the journal Communications Biology, is the oldest Cretaceous tyrannosaur species yet discovered in North America, narrowing a 70-million-year gap in the fossil record of tyrant dinosaurs on the continent.
“With a lethal combination of bone-crunching bite forces, stereoscopic vision, rapid growth rates, and colossal size, tyrant dinosaurs reigned uncontested for 15 million years leading up to the end-Cretaceous extinction — but it wasn’t always that way,” said Lindsay Zanno, paleontologist at North Carolina State University in the US.
“Early in their evolution, tyrannosaurs hunted in the shadows of archaic lineages such as allosaurs that were already established at the top of the food chain,” Zanno said in a statement. Medium-sized, primitive tyrannosaurs have been found in North America dating from the Jurassic — around 150 million years ago. By the Cretaceous — around 81 million years ago — North American tyrannosaurs had become the enormous, iconic apex predators we know.