Forget about the famous dinosaur pictured with protruding teeth. This terrible predator might not have had the head it was given for over a century.
Popular, but also scientific, images often tend to represent large carnivorous dinosaurs such as tyrannosaurus rex With exposed teeth, somewhat similar to the jaws of crocodiles, that is, without covering the lips. However, a new study suggests that, from this point of view, these dinosaurs would have resembled lizards or Komodo dragons. These do indeed have lips that come to cover their teeth when their mouth is closed.
Some studies had already put forward the idea that, as theropods are known to have teeth covered in a relatively thin layer of enamel, it is possible that these required lip protection to prevent their premature wear. But this hypothesis has not yet been proven.
Tyrannosaurs that would have had more lizard heads than crocodiles
And so the researchers tested the significance of several facial reconstructions, by evaluating links between skull length and tooth size for many theropod dinosaurs, but also for living and extinct species of reptile. They also performed a comparative histological analysis of tooth wear patterns in tyrannosaurs and crocodiles.
Their results have been published in scienceAlthough related to crocodilians, theropods did not show signs of wear and tear on the outer surface of their teeth, indicating the presence of tissues (such as the lips) or oral secretions to moisturize and protect them. In addition, the relationship between tooth size and skull length is somewhat similar to that observed in modern reptiles.
Therefore, the researchers suggest that the teeth of tyrannosaurs were completely covered by the lips. A novelty in the facial morphology of these large predators that could have implications for our understanding of jaw anatomy and foraging ecology.
