Toothy Dino Terrorized Utah Before T. Rex


A newly discovered early relative of Tyrannosaurus rex was a fearsome predator in what's now southern Utah about 80 million years ago, according to a study.

“King of Gore” (Lythronax argestes) had looks and a lifestyle to match its name. Described in the latest issue of the journal PLoS ONE, it was by far the scariest large predatory dinosaur alive at that time during the Late Cretaceous Period.

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“We thought that Lythron, or gore in Greek, exemplified its presumed lifestyle as a predator with its head covered in the blood of a dead animal,” lead author Mark Loewen, a research associate at the Natural History Museum of Utah, told Discovery News. The dino co-existed with the largest alligator that ever lived, 40-foot-long Deinosuchus, which it probably avoided in favor of easier prey.

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“(Lythronax's) forward-facing eyes, powerful limbs and large size would have made it an efficient hunter of both duckbilled dinosaurs and horned dinosaurs like Diabloceratops,” added co-author Joseph Sertich, curator of Vertebrate Paleontology at the Denver Museum of Nature and Science.

“A mouthful of knife-edged teeth set in powerful jaws would have made short work of potential prey, carving out huge chunks of flesh and bone to swallow hole,” Sertich continued.

A Bureau of Land Management employee named Scott Richardson first discovered the dinosaur’s fossilized skeleton. For the study, Loewen and his team excavated the remains and analyzed them. They compared 501 skeletal features of Lythronax with those of 54 different other species of known, carnivorous dinos. The paleontologists found that Lythronax is most closely related to T. rex and another dinosaur known as Tarbosaurus bataar.

In terms of size, Sertich said that Lythronax was smaller than T. rex, reaching around 30 feet in length as opposed to 40 plus feet. Lythronax was no lightweight, though, and would have tipped the scales at about nearly 3 tons.

Both “King of Gore” and “Tyrant Lizard King” had about the same number of teeth set in a wide skull. Their snouts were short and narrow, but widened at the eyes to permit binocular vision.

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