T. Revealing the true faces of predatory dinosaurs like the Rex -Se

A recent study challenges the portrayal of predatory dinosaurs Tyrannosaurus rex Along with exposed teeth, they instead had scaly, lizard-like lips. By examining the tooth structure, wear patterns, and jaw morphology of the reptile group, the researchers concluded that theropod facial anatomy resembled that of a lizard more than a crocodile. Findings indicate that many popular dinosaur depictions, including iconic ones jurassic the park T. Rex, wrong. This research provides valuable insights into the appearance, feeding habits, dental health and evolutionary patterns of dinosaurs and other extinctions. the species.

A new study suggests that predatory dinosaurs such as Tyrannosaurus rexAs such there were no permanently exposed teeth as depicted in the film jurassic parkBut instead the scaly, lizard-like lips cover and close their mouths.

Researchers and artists have argued that theropod dinosaurs, the group of two-legged dinosaurs that included carnivores and apex predators T. Rex And VelociraptorBirds, as well, had lipless mouths in which the continuously visible upper teeth hang over their lower jaws, similar to the mouths of crocodiles.

T. Rex skull and head reconstruction. Credit: Mark Witton

However, an international team of researchers challenges some well-known images and says that this dinosaur’s beak was similar to that of lizards and their relatives, the tuatara – a rare reptile found only in New Zealand, which is the last survivor. An order of reptiles that flourished during the age of the dinosaurs.

In the most detailed study of the issue to date, researchers examined tooth structure, wear patterns, and jaw morphology of a group of lipless reptiles and found that theropod mouth anatomy and function are more lizard-like than crocodile-like. It refers to lizard-like mouth tissue, with scaly lips covering their teeth.

These lips were probably not muscular, as they are in mammals. Most reptilian lips cover their teeth but are not freely movable—they cannot be curled back, or make other kinds of movements that we associate with the lips of humans or other mammals.

Study co-author Derek Larson, collection manager and researcher in paleontology at Canada’s Royal BC Museum, said: “Paleontologists often like to compare extinct animals with their closest living relatives, but in the case of dinosaurs, their closest relatives evolved evolutionarily. Millions of years apart. And today is incredibly special.

How similar theropod teeth are to monitor lizards is quite remarkable. From the tiniest dwarf monitor to the Komodo dragon, teeth work the same way. Thus, monitors can be compared to extinct animals such as theropod dinosaurs based on this similarity of function, even though they are not closely related.”

Tyrannosaurus rex closes its mouth and bellows like a croaking crocodile. If its mouth is closed, T. All of the rex’s huge teeth will disappear behind its lips. Credit: Mark Witton

From co-author Dr. Mark Witton University of Portsmouth said: “Dinosaur artists have come back to beaks since the 19th century when dinosaurs began to be reconstructed, but beakless dinosaurs became more prominent in the 1980s and 1990s. They then became deeply ingrained in popular culture through movies and documentaries — Jurassic Park and its Sequels, Walking With Dinosaurs etc.

“Curiously, there was not a dedicated study or discovery to stimulate this change and, it probably reflects a preference for a new, ferocious-looking aesthetic rather than a change in scientific thinking. We present this popular depiction of lizard-like lips covering teeth. It means Many depictions of our favorite dinosaurs are wrong, including the iconic Jurassic Park T. Rex“

The results, published in the journal scienceIt was found that tooth wear in lipless animals was markedly different than that of carnivorous dinosaurs, and that dinosaur teeth were no larger relative to the size of skulls than modern lizards, suggesting that they were not large enough to be covered by lips.

A half-grown tyrannosaurus, sporting a full set of beaks, walks under Struthiomimus, a beaked ostrich dinosaur. Credit: Mark Witton

Also, the distribution of small foramina around the jaws, which supply nerves and blood to the gums and tissues around the mouth, was more lizard-like among dinosaurs than crocodiles. Moreover, modeling of lipless theropod jaw closure shows that the lower jaw had to either crush the jaw-supporting bones or dislocate the jaw joint to close the mouth.

“As any dentist will tell you, saliva is important for maintaining the health of your teeth. Teeth that are not covered by saliva are at risk of drying out and can be more damaged during feeding or fighting, as we see in crocodiles, but not in dinosaurs,” says Kirstin Brink, assistant professor of paleontology at the University of Manitoba.

He added: “Dinosaur teeth have very thin enamel and mammal teeth have thick enamel (with a few exceptions). Crocodile enamel is slightly thicker than dinosaur enamel, but not as thick as mammalian enamel. There are some groups of mammals that have exposed enamel, but their enamel has changed to withstand exposure.”

A one-sheet summary of key findings and research conclusions. Credit: Mark Witton

Thomas Cullen, assistant professor of paleobiology at Auburn University and lead author of the study, said: “While it has been argued in the past that the teeth of predatory dinosaurs may have been too large to be covered by beaks, our research shows that, in fact, their teeth were generally not large. Even the giant tyrannosaurs The teeth are also proportionally similar to the size of living predatory lizards, when compared to the size of the skull, rejecting the idea that their teeth were too large to be covered by the beak.”

The results provide new insights into how we reconstruct the soft tissue and appearance of dinosaurs and other extinct species. This can provide important information about how they feed, how they maintain their dental health, and broader patterns of their evolution and ecology.

Dr Witton said: “Some people think that we are ignorant of the appearance of dinosaurs beyond basic features such as the number of fingers and toes. But our study, and others like it, show that we have an increasingly good handle on many aspects of dinosaur appearance. From being unknown Far from it, we’re now at a point where we can say ‘Oh, it doesn’t have beaks? Or a certain type of scale or feathers?’ Then it’s a realistic image of a tiger without the stripes of that species.”

The researchers noted that their study did not suggest that any extinct animal had exposed teeth — some, such as saber-toothed carnivorous mammals, or marine reptiles and flying reptiles with extremely long, interlocking teeth, almost certainly did.

For more information on this study, see Deadly Teeth of T. Rex Way’s Hidden Behind Scaly Lips.

Reference: Thomas M. Cullen, Derek W. Larson, Mark P. Witton, Diane Scott, T. Maho, Kirstin S. Brink, David C. “Theropod Dinosaur Facial Reconstruction and the Importance of Soft Tissue in Paleobiology” by Evans and Robert Reiss, 30 March 2023, science.
DOI: 10.1126/science.abo7877