New T. Rex Relative Discovered in Utah, Named 'King of Gore'

Lythronax argestes predates T. rex by ten million years.

November 7, 2013, 1:47 PM

Nov. 7, 2013— -- Tyrannosaurus rex just found a new member in its family tree. Researchers at the Natural History Museum of Utah and the Denver Museum of Nature and Science recently published a paper detailing the new species of dinosaur Lythronax argestes, whose first name translates to "King of Gore."

Mark Loewen, the lead author of the study that was published in the online journal PLoS ONE, found 80-million-year-old bone fragments of the new dinosaur in Grand Staircase-Escalante National Monument in Utah. "Finding a predator here is pretty rare," he told ABC News. Herbivores, like the duck-billed hadrosaurs or the multi-horned certaopsians, vastly outnumbered any carnivore. "For every hundred hadrosaurs or ceratopsians, you might find one tyrannosaur."

Though there are a handful of species that belong to the tyrannosauridae family, the T. Rex and Lythronax argestes are notable because of the wide backs of their skulls. Due to their skull shape, the dinosaurs' eyes would face forward, giving them binocular vision and the ability of depth perception.

Loewen said that the new fossil indicates that binocular vision, a hallmark of the T. rex, may predate the large carnivore with tiny arms by 10 to 12 million years. "At 80 million years old, Lythronax argestes represents what the T. rex would have come from," he said. Since other tyrannosaur species lack binocular vision, Loewen also believes that there's another ancestor, as well as several branches of the tyrannosaur family, that are waiting to be discovered.

Several different bone types of the new fossil were found, including parts of the skull, hips, legs and tail. Loewen estimates that the dinosaur was around 8 feet high, about 24 feet long, and weighed up to 3 tons. "It's not as big as a T. rex," he said. "But this animal is more like a teenager. The adult could have weighed up to 3.5 tons."

Though the King of Gore shares physical similarities to T. rex, Loewen wouldn't yet call them directly related. "They share a common ancestor," he said. "But we don't know exactly what that is. Think of this as an uncle or a cousin to the T. rex."