Movies like Jurassic Park have given us a bare-fanged image of the Tyrannosaurus Rex that only enhanced its fearsome legacy. Now researchers believe the dinosaurs' predator king might have had more in common appearance-wise with modern lizards, namely lizard-like lips covering its teeth. The Wall Street Journal reports that a new study published in Science indicates paleontologists have concluded the concepts of T. rex based on their modern relatives like crocodiles might have been in error all along. Study co-author Dr. Mark Witton of the University of Portsmouth tells the Journal that new information makes the old concepts of the apex predator's appearance "pretty indefensible." It's "time that we have a big shake-up of what we think these dinosaurs looked like in wider culture."
Witton pointed out the crocodile-inspired T. rex concepts were based on that reptile's exposed teeth, as well as the idea that the dino's fangs might have been up to six inches. Paleontologists believed it didn't have enough space in its mouth to conceal them. After comparisons between tooth sizes and skull lengths of a variety of living and extinct lizards, research showed that the T. rex's skull-to-tooth size was closer to that of a monitor lizard like the Komodo dragon, which has concealed teeth. Researchers also compared wear patterns on teeth from dinosaur skulls to crocodiles and found they didn't align. There was also likely a key difference in tooth durability. Exposed teeth can get easily damaged. The dinosaurs would have been able to regrow new ones, but it would have been costly to the T. rex's health, so having protective lips made sense.
Both the WSJ and the New York Times speak to paleontologist Thomas Carr of Wisconsin's Carthage College, who expressed skepticism of the study. Carr told the Times that Witton's team didn't take into account different known aspects of Tyrannosaur physiology. Carr said T. rex dentin (a layer of material underneath tooth enamel) was "arguably structurally more important to a Tyrannosaur" than its outer enamel layer "because if the dentin shatters, then they’ll be eating bananas.” According to Carr, Tyrannosaurs didn't need to keep their teeth moist, under protective lips, in order to maintain strength. Carr went on to say that no one will truly know whether the mighty T. rex had lips or not without an actual fossilized face. (Read more science stories.)