Scientists have refuted the opinion about tyrannosaurs: they had lips

New research shows that prehistoric tyrannosaurs had teeth covered by lips. So, contrary to the description in movies like Jurassic Park, scientists now believe that carnivorous dinosaurs were not “toothy, lipless creatures.”

While Tyrannosaurus Rex is often depicted prowling the landscape with a toothy grin, its intimidating teeth may actually have been hidden behind a pair of thin, scaly lips, research suggests.

Experts say the notion that carnivorous dinosaurs were lipless arose because of the sheer size of their teeth, and because their closest living toothed relatives like crocodiles and alligators don’t have lips.

However, a new study suggests that, like modern lizards, theropods may have had their teeth covered when their mouths were closed.

Dr Mark Whitton of the University of Portsmouth and co-author of the study argues that popular depictions of dinosaurs are outdated.

“Basically, we are still living in the shadow of 30-year-old Jurassic Park,” says the scientist. “We need to move away from this toothy, lipless image of creatures like the Tyrannosaurus rex and move on to these animals with more lizard-like faces.”

Researchers from the US and UK write in the journal Science that a study of a large tooth that spent more than 500 days in the mouth of a Tyrannosaurus rex daspletosaurus showed no signs of significant wear – the find is consistent with studies of the teeth of other theropods.

In contrast, the large teeth of American alligators are often damaged, even with a layer of dentin worn away – researchers suggest that this is the result of these animals being devoid of lips, which means that their tooth enamel is exposed, which makes it dry and less resistant to wear. .

Whitton said tyrannosaur teeth often lasted more than 12 months before they were replaced – much longer than those of crocodiles – lending weight to the idea that prehistoric reptiles had lips.

“No animal can repair or replace worn enamel, and yet the thin enamel of tyrannosaurs remains intact, even though some retained their teeth for over a year,” Dr. Witton said.

According to a study published in the Journal of Vertebrate Paleontology, the fossilized remains show a mammalian foot in the thorax of a microraptor.

The team also found tiny openings in theropod jaws, similar to those of modern lizards, where they supply the lips and gums with nerves and blood vessels, while both have upright teeth, unlike crocodiles, whose teeth jut outward.

The team said an analysis of the relative sizes of the skull and teeth in lizards conducted today showed that theropod teeth were not too large to be closed lips.

“If you just imagine a Komodo dragon to scale with a 5-foot-long skull, it doesn’t look much different from something like a Tyrannosaurus rex,” Witton said.

Professor Steve Brusatte of the University of Edinburgh, who was not involved in the work, notes that if the researchers are correct, then T-Rex would not have had a toothy grin, but rather a gummy smile, adding that the soft tissues covering their teeth would not have been. the same shape as our own fleshy and plump lips.

However, Brusatte believes that the case is not yet closed. “I suspect these researchers are right and that tyrannosaurs had more soft tissue covering their teeth than crocodiles, but I still doubt if they had as much material covering their teeth as monitor lizards.” he said.