T. rex fossil unearthed decades ago is older, more primitive relative of iconic dinosaur, scientists say

The Tyrannosaurus rex seemingly came out of nowhere tens of millions of years ago, with its monstrous teeth and powerful jaws dominating the end of the age of the dinosaurs.

How it came to be is among the many mysteries that paleontologists have long tried to solve. Researchers from several universities and the New Mexico Museum of Natural History and Science say they now have one more piece of the puzzle.

On Thursday, they unveiled fossil evidence and published their findings in the journal Scientific Reports. Their study identifies a new subspecies of tyrannosaur thought to be an older and more primitive relative of the well-known T. rex.