What if Jurassic Park and most toymakers showing fanged tyrannosaurs rex were wrong? These famous dinosaurs most likely had lips covering their teeth, according to a study published Thursday. "Animals like T-Rex, theropod dinosaurs, most likely had some kind of lips, soft tissue, covering their mouths to protect their teeth," Thomas Cullen, one of the authors of the study, told AFP. the journal Science.
"It's a change from many hypotheses so far which were that they looked more like crocodiles, with teeth showing when their mouth was closed and no lips," adds this professor of paleobiology at the University of 'Auburn, Alabama in the southern United States. If the question is not completely settled, the researchers studied a panel of theropod dinosaurs from several museums to arrive at this new conclusion.
They have, for example, compared the wear of the enamel of the teeth of dinosaurs and crocodiles, the living animals closest to these theropods. Tooth enamel "needs to stay hydrated to stay healthy," says Cullen. "If it's exposed to the air for too long, it becomes crumbly and it's more likely to crack or get sick. According to the paleobiologist, the enamel on the outer part of the teeth of living crocodiles wears out faster than that on the inner part because they have no lips.
"When we looked at the enamel thickness on the inside and outside of the teeth of large tyrannosaurs, they didn't show this type of configuration, like a crocodile," he continues. "They have a more animal-like model with lips," says Thomas Cullen. "The thickness of their enamel is the same on the outer and inner sides. »
Researchers also wanted to know if T-Rex teeth could have been simply too big for their mouths by comparing them to many modern lizards with lips. "Some monitor lizards today have absolutely huge teeth," Cullen pointed out. "It seems almost unbelievable that these teeth could be completely covered by lips. Yet it is. And we found that […] this scale ratio is almost identical for theropod dinosaurs. »
What are the consequences for the representation of these famous predators in popular culture? While Thomas Cullen acknowledges that the Jurassic Park films managed to "stick to what was known" about dinosaurs "at the time", attempts to portray theropods faithfully have since "gone completely off the rails", according to him.
