T. rex’s terrifying teeth would have been hidden behind scaly lips

The enamel of Tyrannosaurus rex and different predatory dinosaurs would have been hidden behind scaly lips, which they couldn’t even pull again to reveal their superior fangs, opposite to movie and TV depictions.

That is the conclusion of a staff that has been learning the enamel of residing reptiles similar to alligators as properly of these of historical theropod dinosaurs, which embrace Velociraptor, Spinosaurus, tyrannosaurs and Giganotosaurus. “We need to update what the popular idea of a dinosaur is,” says Mark Witton on the University of Portsmouth, UK.

The case for a rethink put ahead by Witton and his colleagues centres on tooth put on. Teeth which might be at all times uncovered ought to put on out extra shortly than these stored contained in the mouth.

This isn’t simply to do with being bodily shielded. If tooth enamel isn’t continuously stored moist by saliva, it dries out and turns into extra brittle, says Witton.

When the staff examined the uncovered enamel of contemporary alligators, it revealed important put on, with a lot of the enamel worn away. “It’s like someone took sandpaper to it,” says Witton.

By distinction, the staff discovered that fossil enamel from theropod dinosaurs had been in actually good situation, regardless that these dinosaurs didn’t substitute their enamel as usually as crocodilians do.

“That just isn’t consistent with them being outside the mouth like a crocodile,” says Witton.

The examine additionally factors out that many residing predatory lizards have hidden enamel. For occasion, the crocodile monitor lizard (Varanus salvadorii) has larger enamel relative to its cranium dimension than T. rex. Yet solely the very suggestions of those enamel will be seen when its mouth is vast open, as a result of the enamel aren’t solely coated by its lips, but in addition sheathed in gentle gum tissue that’s pushed again by no matter it bites.

“In consequence, they actually bite into and cut their own gums sometimes,” says Witton.

“I suspect they are right, and that tyrannosaurs had more soft tissue covering their teeth than crocodiles, but I’m still on the fence as to whether they had as much stuff covering their teeth as monitor lizards,” says Steve Brusatte on the University of Edinburgh, UK.

There has been plenty of debate about tyrannosaur lips in recent times, says Brusatte, nevertheless it isn’t clear if T. rex was extra like a crocodile or a lizard. “There is no good, modern-day analogue for a bus-sized superpredator with the head the size of a bathtub that crushed the bones of its prey.”

Witton doubts the examine will persuade Hollywood to vary its dinosaur depictions. He factors out that film-makers have been reluctant so as to add feathers to display screen dinosaurs regardless that the proof that many had this characteristic is indeniable. So far, no T. rex fossils with feathers have been discovered, although.

“We’re decades behind the times in terms of portraying dinosaurs in cinema. We’re still in the age of Jurassic Park,” says Witton. “It’s getting a bit desperate at this point because they are so not reflecting what we think these animals looked like anymore.”