Meet T. rex's Ancestor: The Hunter Wash Tyrannosaur

A significant fossil discovery in northwestern New Mexico is reshaping our understanding of Tyrannosaurus rex and its lineage. A shinbone, or tibia, dating back about 74 million years to the Cretaceous Period, has been analyzed and identified as belonging to a close relative of T. rex.

This ancient predator, unofficially named the Hunter Wash tyrannosaur after its discovery site, potentially represents a direct ancestor to T. rex. The tibia, measuring 3.2 feet long, is roughly 80% the size of the largest known T. rex specimen and indicates a dinosaur weighing approximately 4.7 tons.

Researchers suggest this tyrannosaur was the largest of its kind at that time, predating T. rex by several million years. While the fossil strongly suggests a close relationship, possibly even an ancestral one, scientists emphasize that more complete remains, particularly a skull, are necessary to confirm its exact place in the tyrannosaur family tree.

The Hunter Wash tyrannosaur roamed North America during a period when the continent was divided by a vast seaway. Its discovery adds to growing evidence that the Tyrannosaurus genus may have evolved in the southern parts of Laramidia, the western landmass of North America.