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An artist’s rendering of the newly discovered tyrannosaur Daspletosaurus horneri.

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Dino Pulerà

With its dagger teeth and formidable frame, the Tyrannosaurus rex was one of the most frightening beasts to ever terrorize the land. Yet despite all its fame, the dinosaur’s looks remain a bit of a mystery.

Now, after studying a well-preserved fossil of a newly discovered T. rex relative, paleontologists think they have revealed some important features of the predator’s fearsome face.

“We have unmasked tyrannosaurs,” said Thomas Carr, a paleontologist from Carthage College in Wisconsin, and lead author of a study published Thursday in the journal Scientific Reports.

He and his team found that the dinosaur family had no lips and had faces covered with small patches of armored skin and large, flat scales more similar to crocodiles than to lizards. Behind their eyes on each side of the head there was a large horn that may have been covered in keratin, the material that makes a person’s fingernails and a bird’s beak. The team also discovered that tyrannosaur snouts and jaws were most likely laced with nerves that made their skin supersensitive, comparable to a human’s fingertips. The extra sensitivity may have aided the tyrannosaurs in hunting and could have helped shape the family into efficient killing machines.

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Thomas D. Carr

“It paints a really terrifying picture of not only this new species, but also of other tyrannosaurs, like T. rex, that would have had these same features,” said Stephen Brusatte, a paleontologist from the University of Edinburgh who reviewed the paper. “Bone-crunching predators bigger than a school bus, their faces covered in mangy scales, using not only their nose to smell you out, but their snouts to literally sense you out in a way that we can’t even comprehend since we don’t have that same type of sensory system.”

Dr. Carr and his colleagues made their conclusions based on a tyrannosaur specimen that was found 25 years ago, but only just now got a name. It is a new species known as Daspletosaurus horneri, or “Horner’s Frightful Lizard,” named after Jack Horner, a renowned paleontologist. The beast roamed present-day Montana 75.2 to 74.4 million years ago and feasted upon crested duckbill dinosaurs. The specimen they studied had specific textures covering its skull. They formed a sort of Venetian mask that revealed the patterns covering just about every part of the face but the eyes and the nose. From the imprints on the skull, they were able to reconstruct the types of soft tissue covering the face.

Presently, paleontologists do not have good samples of fossilized facial skin in carnivorous dinosaurs, most likely because the face is one of the first parts of a dinosaur to get scavenged or eroded once it died, according to Thomas Richard Holtz, a paleontologist from the University of Maryland who was not involved in the study. He said that he agreed with the new study’s findings in that the bone texture on the fossil’s jaws did seem inflated and rough, indicating that the tyrant dinosaur had a face more like that of crocodiles than of lizards.

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The team also concluded that the snout and jaws were particularly sensitive based on tiny holes they found speckled throughout them. The holes, known as foramina, have also been found in crocodiles and are thought to have housed hundreds of trigeminal nerves. In present- day animals, the special nerves are thought to enable birds to navigate long distances, allow pit vipers to detect infrared radiation from warm bodies and let alligators lurking in murky waters sense slight vibrations to catch prey.

By comparing the nerve holes in the tyrannosaurs with that of present-day crocodiles, the team speculates that the tyrannosaurs would have used their heightened senses to detect the temperatures of their nests, tend to their eggs and may have used their sensitive snouts to nuzzle their mates.

“No one would have predicted that a land animal like a tyrannosaur would turn their entire face into a finely tuned sensory organ,” Lawrence M. Witmer, paleontologist from the Heritage College of Osteopathic Medicine at Ohio University who was not involved in the study, said in an email. “Maybe if you’re a bigheaded beast with tiny hands and a small brain, you have to do something special!”

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