A 2.5-ton relative of Tyrannosaurus rex with knife-like teeth and eyes made for hunting has been given the title King of Gore.
The 7.3-metre-long carnivore lived 80 million years ago, about a dozen million years earlier than T. rex. Its outstanding features were a wide rear skull, short narrow snout and forward-looking eyes.
Scientists named the creature Lythronax argestes, which can be translated as ‘King of Gore of the Southwest’, a reference to its fierce appearance and the location where it was found.
The predator, which like T. rex stood on two legs, inhabited Laramidia, a land mass formed on the western coast of a shallow sea that once split north America in half.
Its remains were discovered in Grand Staircase-Escalante National Monument in Utah, a 0.76 million-hectare rugged desert region that has yielded a treasure trove of dinosaur fossils.
Mark Loewen, from the University of Utah, who led a study of Lythronax published in the online journal Public Library of Science One, said: “The width of the back of the skull of Lythronax allowed it to see with an overlapping field of view, giving it the binocular vision, very useful for a predator and a condition we associate with T. rex.”
Scientists have recently shown that dinosaurs from southern Laramidia, covering Utah, New Mexico, Texas and Mexico, differ at the species level from those from the north.
Lythronax and its southern relatives are more closely related than the long-snouted tyrannosaurids from northern Laramidia.
Co-author Joseph Sertich, from the Denver Museum of Nature & Science, said: “Lythronax may demonstrate that tyrannosaurs followed a pattern similar to what we see in other dinosaurs from this age, with different species living in the north and south at the same time.”
The width of the back of the skull of Lythronax allowed it to see with an overlapping field of view, giving it the binocular vision, very useful for a predator
Randall Irmis, from the Natural History Museum of Utah, said: “Lythronax and other tyrannosaurids diversified between 95-80 million years ago, during a time when North America’s interior sea was at its widest extent. The incursion of the seaway on to large parts of low-lying Laramidia would have separated small areas of land from each other, allowing different species of dinosaurs to evolve in isolation on different parts of the land mass.”
Over the past 14 years teams from the National History Museum of Utah, the Denver Museum of Nature & Science and several other institutions have unearthed more than a dozen new species of dinosaur from the same region.
They include duck-billed hadrosaurs, armoured ankylosaurs, horned dinosaurs and carnivorous theropods, dinosaurs that stood on two legs.
Philip Currie, another co-author from the University of Alberta in Canada, said: “Lythronax is a wonderful example of just how much more we have to learn about with world of dinosaurs. Many more exciting fossils await discovery in Grand Staircase-Escalante National Monument.”