New tyrannosaur discovered in Utah

If you thought Tyrannosaurus rex was one of the most terrifying predators to ever exist, wait ‘til you see his great uncle.

 

Meet Lythronax argestes, a narrow-snouted, bipedal predator that terrorized the Mesozoic landscape some 80 million years ago. First unearthed in 2009 at the Grand Staircase-Escalante National Monument in southern Utah, Lythronax bears the distinction of being the oldest member of the Tyrannosaurid family found so far. The discovery, publicly announced Wednesday at the Natural History Museum of Utah, was one of the highlights of a study published on the online science journal PLOS ONE. The researchers examined the effect of rising sea levels during the Late Cretaceous Period on the diversity of non-marine vertebrates, specifically the Tyrannosaurid family.

 

 

 

 

Based on the incomplete skeleton recovered (which included skull fragments and a few bones from the animal’s spine and hip), Lythronax had binocular vision, indicating overlapping vision – a quality it shared with its younger, more well-known relative. Combined with its short snout and wide rear skull, paleontologists deduced that the predator had the ability to look forward and perceive depth, allowing it to become a more effective hunter.

 

According to Mike Loewen, an adjunct assistant professor from the University of Utah who led the study, the remains are presumed to have been from a teenage specimen, estimated to have stood 8 feet tall at the hip, with feathers running along its back and tail that were at least 6 inches long. It is believed that an adult Lythronax could have reached at least 30 feet in length and more than 2 tons in weight.

 

In an interview with BBC News, Dr. Randall Irmis, who co-authored the study, revealed that the predator was given the genus Lythronax, meaning “king of gore”, to reflect its fearsome and carnivorous nature. Dr. Irmis added that the species name argestes was derived from Greek poet Homer’s name for wind coming from the south-west. Lythronax appears to have been closely related to tyrannosaurids from Utah, Texas, New Mexico, and Mexico (which formerly comprised the southern part of the prehistoric continent Laramidia) – an evolutionary “branching out” resulting from the expansion of the Western Interior Sea and the subsequent isolation of land masses.

 

The discovery of Lythronax sheds new light on the development of the tyrannosaurid family tree. The new findings point to a “mainly North American evolution for the group,” according to Mike Benton of the University of Bristol in UK. The results of the study also suggest that, as BBC News puts it, "the age of discovery is far from over."

 

The Lythronax fossils are currently on display in the museum, as part of its Past Worlds Gallery. — TJD, GMA News