The Tyrannosaurus rex family continues to expand with this new species, Lythronax argestes. The new tyrannosaurid shares a common ancestor with T-rex, and while much older, also shares much of the same skull construction. Later tyrannosaurids like T-Rex had larger jaw muscles and binocular vision, a trait Lynthronax also possesses.
Lythronax lived on Laramidia, along the western shores of the great seaway that separated North America; this landmass hosted a vast array of unique dinosaur species and served as the crucible of evolution for iconic dinosaur groups such as the horned and duck billed dinosaurs.
As noted by American palaeontologist Tom Holtz of the University of Maryland, “This new discovery also supports the idea that the giant thick-toothed Asian tyrants Zhuchengtyrannus and Tarbosaurus were immigrants from North America rather than their own Asian line, because they share a common origin with Lythronax and Tyrannosaurus.”
The evolutionary path of the tyrannosaurids has been a subject of debate, but there has been a batch of new species in the past decade or so that have helped paint a fuller picture of ancient life. And I suspect there are much more discoveries just waiting to be found and written up.
And more tyrannosaurids mean more dinosaurs to be brought back to life in films to eat people!
Loewen, M., Irmis, R., Sertich, J., Currie, P., Sampson, S. 2013. Tyrant dinosaur evolution tracks the rise and fall of Late Cretaceous oceans. PLoS ONE 8, 11: e79420. doi:10.1371/journal.pone.0079420