New Mexico Fossil Suggests 4-5 Ton Tyrannosaur Lived 74 Million Years Ago

1 articles · Updated · Sci.News · May 15

A 96-cm tyrannosaur tibia from New Mexico’s Kirtland Formation points to a predator weighing about 4 to 5 tons, making it the oldest known giant tyrannosaur yet identified in North America.
The shinbone is about 84% as long and 78% as thick as the largest known Tyrannosaurus specimen, and its anatomy most closely matches an early member of Tyrannosaurini rather than a giant Bistahieversor.
Phylogenetic analysis led the team to favor the idea that the fossil came from an early relative of T. rex, though they said an unknown giant lineage cannot be fully ruled out.
The find pushes back the emergence of giant tyrannosaurs to the Late Campanian and supports the view that these oversized predators arose in southern Laramidia rather than first evolving in Asia.

Did a mysterious giant, an older cousin to T. rex, once rule ancient New Mexico?

Why did giant tyrannosaurs evolve in America's south millions of years before anywhere else?