Utah Paleontologists Discover New Tyrannosaurus Species

Nov 6, 2013

Paleontologists working in the fossil beds of Grand Staircase Escalante National Monument have discovered a new dinosaur species, a close cousin of Tyrannosaurus Rex. A new study shows the bones found are now some of the oldest in this predator’s lineage.

Mark Loewen is a Research Associate at the Natural History Museum of Utah. He shows visitors the skull and 24-foot model skeleton of a new dinosaur species with a fitting name.

"This animal which we’ve named Lythronax argestes, the name actually means 'gore king from the southwest,'" Loewen says.

The name fits the unusual find since the monument’s Wahweap rock formation, where Lythronax was found, isn’t typically fossil rich, and also where Tyrannousaur numbers were low as the dominant predator in the food chain.

Randall Irmis is the Curator of Paleontology for the museum. Along with Loewen, the two are lead authors in a study explaining the new find. Irmis says they were certain this was a distinct species when they closely looked at its skull.

"The most defining feature of the skull when you look at it head on is that it’s got a very narrow snout, and a very wide back of the skull," Irmis says.

He says this gave Lythronax binocular vision to hunt and attack prey in coastal areas of a shallow sea that covered the western U.S. 80 million years ago. This area also included isolated islands where new dinosaur species could evolve into those like the great Tyrannosaurus Rex. Irmis says the real story is about how ecosystem changes affected species evolution during that time period.

"Changes in sea level, global events, actually had an effect on all the different types of dinosaurs and other organisms that we find, and really provide insights into why we’re finding so many new dinosaur species here in Utah and other places throughout western North America," he says

The new Lythronax display joins other Tyrannosaur specimens at the museum. Some scientists are calling it a family reunion.