SALT LAKE CITY — Weighing in at more than 2 tons and at least 2 dozen feet long, a new species of dinosaur related to Tyrannosaurus Rex was fierce enough to be dubbed "King of Gore."
The discovery of "Lythronax argestes" at the Grand Staircase-Escalante National Monument in southern Utah was announced Wednesday at the Natural History Museum of Utah and coincides with the publication of a study in PLOS ONE, an open access scientific journal.
The study, funded by Bureau of Land Management and the National Science Foundation, was led by Mark Loewen, research associate at the Natural History Museum of Utah and adjunct assistant professor in the Department of Geology and Geophysics at the University of Utah.
Scientists say the discovery of Lythronax is particularly noteworthy because of what it reveals about the tyrannosaur family, which is a group of small- to large-bodied bipedal carnivorous dinosaurs. Previously, paleontologists believed this type of wide-skulled tyrannosaurid only appeared 70 million years ago, whereas Lythronax shows it had evolved at least 10 million years earlier.
That finding, said Loewen, means Lythronax is the "great uncle" to the T-Rex.
The discovery has significance beyond finding another new dinosaur, spinning a fascinating tale about the uniquely evolutionary nature of the dinosaurs that once roamed North America.
"This unveils a brand new family tree," Sertich said. "It has really unlocked an amazing story about how these animals evolved."
Among his contemporaries, Lythronax is unique because of the size of his skull, which is much wider. Paleontologists believe that gave him "binocular vision," which would have been incredibly useful in his role as a predator.
Asked during a press conference what Lythronax would have eaten, Loewen quipped: "Whatever it wants."
Lythronax, the largest carnivore in the ecosystem, lived 80 million years ago during the Late Cretaceous period when western North America was an island continent called Laramidia. His discovery at the Grand Staircase-Escalante National Monument by BLM's Scott Richardson in 2009 adds to a bevy of new dinosaurs unearthed at the monument, which spans 1.9 million acres of high desert terrain that was the last area in the contiguous United States to be mapped.
Over the last 14 years, scientists have found more than a dozen species of dinosaurs at the monument, leading them to dub it the largest bone yard in North America, offering enticing discoveries to come.
Paleontologists are intrigued that the dinosaurs of southern Laramidia — which is Utah, New Mexico, Texas and Mexico — "differ" at the species level from their counterparts in the north in Montana, the Dakotas and Canada. Such distinctions coexisting at the same time are curious given that a determined dinosaur would have been able to walk from Alaska to Mexico if time permitted.
The iconic "super-sized" supersized dinosaurs so many are familiar with — such as Tyrannosaurus Rex — actually evolved from ancestors here in North America, said Alan Titus, paleontologist at the monument.
"It is such a unique crucible for the evolution of these animals," he said. "The legacy of these dinosaurs is only found here in North America."
Loewen said paleontologists weren't sure at first what they had when they found the fossils of the Lythronax. Their journey to determine if it was indeed truly a unique species of dinosaur took them to other museums and collections around the globe. The specimen, which they figure was a teenager, stood 8 feet tall at the hip and had 6-inch-long feathers along its back and tail. As an adult it would have grown to 30 feet long.
Their research also revealed for the first time that the isolated island of southern Laramidia would have had snow-capped mountains in its landscape that sat in contrast to its coastal waters and palm trees.
The King of Gore has been pieced together in his skeletal form and is on display at the museum's Past Worlds Gallery, in addition to two skulls belonging to the species.
Additional collaborative authors of the study include Randall Irmis (Natural History Museum of Utah and Dept. of Geology and Geophysics, University of Utah), Joseph Sertich (Denver Museum of Nature & Science), Dr. Philip Currie (University of Alberta), and Scott Sampson (Denver Museum of Nature & Science).
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