In 1983, researchers uncovered a partial skull near Kettle Top Butte in southeastern New Mexico, and after years of reevaluation, scientists now identify it as belonging to a distinct Tyrannosaurus species, named Tyrannosaurus mcraeensis. This newly recognized dinosaur predates the renowned T. rex and shares comparable size but exhibits subtle differences, such as a shallower and more curved lower jaw and lower-positioned hornlets above the eyes. About 25% of the skull has been collected, with significant portions, including the braincase and upper jaws, still undiscovered.

Paleontologist Nick Longrich of the University of Bath highlights the consistent differences observed in various bones of T. mcraeensis when compared to known T. rex specimens. These disparities, particularly above the eyes, are suggested to have implications for the dinosaur’s feeding habits and mate selection. Contrary voices in the scientific community express skepticism, arguing that the purported distinctions may be attributed to relative maturity and individual variation. Additionally, there is controversy over the estimated age of the fossil, with some disputing the proposed timeline of 71–73 million years. Despite the ongoing debate, the discovery challenges existing notions of Tyrannosaurus evolution. The existence of T. Mcraeensis suggests that giant Tyrannosaurus species evolved millions of years earlier than previously believed and originated in southern North America, prompting a reconsideration of the timeline and geographic distribution of these formidable creatures. This finding adds another layer of complexity to the understanding of dinosaur evolution during the twilight of the prehistoric era.