An old relative of the T. rex sparks new questions about the dinosaur's origins

A rendering of Tyrannosaurus mcraeensis, a newly identified relative of T. rex. A partial skull on view at the New Mexico Museum of Natural History and Science was key to the discovery. (Sergey Krasovkiy/NMMNHS)

Researchers say they have identified a new species of Tyrannosaurus that traces the dino's lineage to North America much earlier than previously thought, and could shed new light on the murky origins of the Tyrannosaurus rex.

T. mcraeensis, the newly named species, is the closest known relative of the T. rex, according to a paper recently published in the scientific journal Nature.