Lythronax argestes was huge carnivore that inhabited Laramidia, an island landmass formed on the western coast of a shallow sea that flooded the central region of North America 80 million years ago, scientists at the University of Utah reported Wednesday.
It had several unique features not shared by all of its tyrannosaurus cousins, including a short narrow snout in a skull that was wide in the back and carried forward-oriented eyes, they 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," study author Mark Lowen said.
Paleontologists had thought this type of wide-skulled tyrannosaurid only appeared around 70 million years ago, whereas Lythronax shows it had evolved at least 10 million years earlier.
Lythronax translates as "king of gore," and the second part of the name, argestes, refers to its geographic location in the American Southwest.
Dinosaurs of southern Laramidia (now Utah, New Mexico, Texas, and Mexico), although belonging to the same major groups, differ at the species level from those on northern Laramidia (now Montana, Wyoming, the Dakotas, and Canada,) the researchers 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," study co-author Joseph Sertich said.