Tyrannosaurus rex had lips over its tooth, analysis suggests | Dinosaurs


Whereas T rex is commonly depicted prowling the panorama whereas sporting a toothy grin, its fearsome tooth may very well have been hid behind a pair of skinny, scaly lips, analysis suggests.

Consultants say the notion that theropods have been lipless arose due to the massive measurement of their tooth, and since their closest residing toothed kin – akin to crocodiles and alligators – don’t have lips.

Nevertheless, the analysis means that, like lizards immediately, theropods might have had their tooth lined when their mouth was closed.

Dr Mark Witton, of the College of Portsmouth and a co-author of the examine, mentioned fashionable depictions of dinosaurs have been outdated.

“We’re mainly nonetheless residing within the shadow of Jurassic Park [from] 30 years in the past,” he mentioned. “We have to transfer away from this toothy lipless search for issues like Tyrannosaurus and in the direction of these animals having extra lizard-like faces.”

Writing within the journal Science, researchers within the US and UK say the examination of a giant tooth that spent over 500 days within the mouth of the tyrannosaur Daspletosaurus revealed no proof of considerable put on – a discovering in keeping with research of different theropod tooth.

Against this, the big tooth of American alligators are sometimes broken, with even the dentine layer worn down – a outcome, the researchers counsel, of the animals being lipless, which means their tooth enamel is uncovered, which is why it turns into dry and fewer proof against put on.

Witton mentioned tyrannosaur tooth typically lasted greater than 12 months earlier than being changed – far longer than for crocodiles – including weight to the thought the previous had lips.

“No animals can restore or exchange worn enamel, and but the skinny enamel of tyrannosaurs stays intact although some retained their tooth nicely over a yr,” he mentioned.

The group additionally discovered tiny holes within the jaws of theropods organized in the same strategy to these in immediately’s lizards – the place they provide the lips and the gums with nerves and blood vessels – whereas each have vertical tooth, not like crocodiles whose tooth lean outwards.

The group mentioned an evaluation of the relative measurement of the cranium and tooth in lizards immediately instructed theropod tooth weren’t too massive to have been lined by lips.

“If you happen to simply think about the Komodo dragon scaled up with a 5ft-long cranium, it’s not going to look a lot totally different from one thing like a T rex,” mentioned Witton.

Prof Steve Brusatte, of the College of Edinburgh, who was not concerned within the work, mentioned that if the researchers have been appropriate, T rex wouldn’t have had a toothy grin however extra of a gummy smile, including that the delicate tissue protecting their tooth wouldn’t be the identical form as our personal fleshy and pouty lips.

Nevertheless, Brusatte mentioned the case was not but closed. “I think [these researchers] are proper, and that tyrannosaurs had extra delicate tissue protecting their tooth than crocodiles, however I’m nonetheless on the fence as to whether or not they had as a lot stuff protecting their tooth as monitor lizards,” he mentioned.


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