A recent study by paleontologists from Bath University, Montana State University, and the New Mexico Museum of Natural History reveals that a large tyrannosaurid dinosaur inhabited what is now New Mexico around 74 million years ago. This discovery involves a 96 cm long tibia, suggesting the dinosaur weighed approximately 4 to 5 tons, making it the oldest known giant tyrannosaurus in North America and potentially the oldest member of the Tyrannosaurini.
The researchers analyzed features of the tibia, finding similarities with later tyrannosaurids like Tyrannosaurus rex. They propose three possibilities regarding this fossil: it could be a large individual of a known species, represent a new giant lineage, or indicate an early tyrannosaurid ancestor. The conclusion favors the latter, suggesting these large tyrannosaurids evolved earlier than previously thought.
Debate exists over the origins of giant tyrannosaurs, with some theories suggesting they began in Asia, while others promote a southern North American origin. This study supports the notion that giant tyrannosaurids evolved in southern Laramidia, contrasting with smaller species in the north. The research emphasizes the distinctiveness of Laramidian dinosaurs and was published in the journal Scientific Reports in March 2026.
