“From this paper forward, our field needs to proceed from the assumption as a default that Nanotyrannus is a valid species,” says Napoli. “There’s a large body of research that needs to be pretty fully re-evaluated.”
If confirmed, the finding could reshape what scientists know about Earth’s most famous prehistoric predator and provide insight into the other carnivores that prowled the late Cretaceous landscape. The authors add that their results may also prompt a sweeping re-analysis of how T.rex grew and developed. Some leading theories, they say, were built upon the assumption that Nanotyrannus fossils represented T.rex during its awkward adolescence a notion the new research might overturn.
“I’m not yet ready to proclaim every smaller tyrannosaur skeleton to be Nanotyrannus. Some of these must be juvenile T. rexes,” says Steve Brusatte, a National Geographic Explorer and a paleontologist from University of Edinburgh in Scotland who has long argued that Nanotyrannus is just a young T.rex. But he says the case for the existence of Nanotyrannus is undeniably strong.
“It’s wonderful when new evidence shows that some of our cherished notions—my cherished notions as a tyrannosaur researcher—are likely to be wrong,” he adds. “That’s science, and with fossils, we always have to be humble with the reality that we are dealing with such small sample sizes, such meagre clues from millions of years ago, and each new discovery has the possibility of upending conventional wisdom.”
