The iconic T. rex and raptor may have looked a little less sinister.
A paper – co-authored by Derek Larson, a member of Victoria’s Royal B.C. Museum’s paleontology department, and a team of international paleontologists – proposed the dinosaurs may not have been the ferocious-looking, teeth-baring creatures we think they were.
Results from their work suggest theropods, like the Tyrannosaurus rex and velociraptor, may not have had exposed teeth when their mouths were closed but instead had a fleshy covering – similar to lips and not unlike those of modern-day lizards.
“For a long time, researchers have suggested that theropod dinosaurs had exposed teeth – like we see with crocodiles – and this has become the pervasive depiction of predatory dinosaurs in films and documentaries,” said Larson, paleontolgy collections manager and researcher at RBCM, in a statement. “Our study overturns that idea and seriously brings into question how we reconstruct what certain dinosaurs look like.”
Larson, with his co-authors, looked to modern examples of lip and tooth structures and from examples like the Komodo dragon, researchers determined the exposed teeth of crocodiles are unique to that group. Covered teeth are more typical and researchers determined more probable in extinct animals.
Auburn University’s Thomas Cullen, the lead author of the study, said in the same statement, “even the giant teeth of tyrannosaurs are proportionately similar in size to those of living predatory lizards, rejecting the idea that their teeth were too big to cover with lips.”
While not indicated in the paper, the researchers acknowledged the fleshy tooth coverings they presume would not be akin to the muscular, mobile lips humans have. They also noted while other extinct animals, like various tusked mammals or flying or marine reptiles, almost certainly had exposed teeth – they do not believe the T. rex and other predatory dinosaurs did.
“Accurately reconstructing an extinct animal has huge implications for inferring the behaviour, diet, and evolution of these organisms,” Larson noted.
Given dinosaurs’ closest modern genetic relatives – crocodiles and birds – are also lipless, Larson said it’s not surprising these depictions have become prevalent. “Paleontologists often like to compare extinct animals to their closest living relatives, but in the case of dinosaurs, their closest relatives have been evolutionarily distinct for hundreds of millions of years and today are incredibly specialized. Many of the similarities that they once shared with dinosaurs are long gone.”
One specimen examined in the study was the Field Museum of National History T. rex nicknamed Sue. Sue’s jaws and teeth will be on display at RBCM starting June 16.
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