Tyrannosaurus rex (T. rex) has always been depicted with sharp teeth protruding from its jaws. They are visible even when its mouth is closed. This description is based on its closest living relative – the crocodile. Additionally, scientists believe the dinosaur’s teeth were six inches (15.2 centimeters) long, too large to fit in its mouth.
But Auburn University paleontologist Thomas Cullen and his team assert that Tyrannosaurus rex and other theropods had scaly, lizard-like lips that covered their massive teeth. If this is true, T. rex might not have looked as scary as we thought.
The extensive study was published March 30 in the journal Science. It compared the skull length and tooth size of more than 20 theropod dinosaur fossils. Scientists also examined the bones of lizards such as Komodo dragons. They found that in each case, the skull was large enough to accommodate the teeth even with the mouth closed. Additionally, the small holes for nerves and blood supply in the gums and tissues of theropod dinosaurs resembled those found in lizards rather than crocodilians.
To test their theory, the scientists analyzed the teeth of Theropods, thought to be the direct ancestors of Tyrannosaurus rex. They found that the enamel was nearly intact. This would not be the case if the teeth are regularly exposed to dry air. Researchers also believe that crocodiles replace as many as 3,000 teeth in their lifetime because they do not have the protection of their lips. However, it took T. rex two years to replace a single tooth. They took this as further evidence that dinosaurs had lips. Scientists suspect that these lips were similar to those of other reptiles. They cover the teeth but lack the muscles to move independently.
“While it was previously thought that the teeth of carnivorous dinosaurs might have been too large to be covered by their lips, our study shows that their teeth were not actually particularly large,” Karen said. “Compared to the size of their skulls, their size was similar to that of extant predatory lizards, negating the idea that their teeth were too large to cover with lips.”
But Thomas Carr, a paleontologist at Carthage College in Wisconsin, isn’t convinced. In 2017, Carr and his team found that the facial bones of theropod dinosaurs were similar to those of crocodiles.
Cullen thinks the debate will continue until someone finds a theropod fossil with intact skin. “Until we find a really rare example of a theropod with facial soft tissue intact, we won’t have a definitive answer. It’s not impossible — it just hasn’t happened yet,” the scientist said.
But Auburn University paleontologist Thomas Cullen and his team assert that Tyrannosaurus rex and other theropods had scaly, lizard-like lips that covered their massive teeth. If this is true, T. rex might not have looked as scary as we thought.
The extensive study was published March 30 in the journal Science. It compared the skull length and tooth size of more than 20 theropod dinosaur fossils. Scientists also examined the bones of lizards such as Komodo dragons. They found that in each case, the skull was large enough to accommodate the teeth even with the mouth closed. Additionally, the small holes for nerves and blood supply in the gums and tissues of theropod dinosaurs resembled those found in lizards rather than crocodilians.
To test their theory, the scientists analyzed the teeth of Theropods, thought to be the direct ancestors of Tyrannosaurus rex. They found that the enamel was nearly intact. This would not be the case if the teeth are regularly exposed to dry air. Researchers also believe that crocodiles replace as many as 3,000 teeth in their lifetime because they do not have the protection of their lips. However, it took T. rex two years to replace a single tooth. They took this as further evidence that dinosaurs had lips. Scientists suspect that these lips were similar to those of other reptiles. They cover the teeth but lack the muscles to move independently.
“While it was previously thought that the teeth of carnivorous dinosaurs might have been too large to be covered by their lips, our study shows that their teeth were not actually particularly large,” Karen said. “Compared to the size of their skulls, their size was similar to that of extant predatory lizards, negating the idea that their teeth were too large to cover with lips.”
But Thomas Carr, a paleontologist at Carthage College in Wisconsin, isn’t convinced. In 2017, Carr and his team found that the facial bones of theropod dinosaurs were similar to those of crocodiles.
Cullen thinks the debate will continue until someone finds a theropod fossil with intact skin. “Until we find a really rare example of a theropod with facial soft tissue intact, we won’t have a definitive answer. It’s not impossible — it just hasn’t happened yet,” the scientist said.
