Paleontologists have long considered Tyrannosaurus rex a North American reptile, but a study now claims that the king of the dinosaurs’ predecessor hailed from the Far East.
The cousin megaraptors likely lumbered from one continent to another via land bridge more than 70 million years ago — perhaps in an attempt to beat the heat, according to an article in the journal Royal Society Open Science. The finding is potentially controversial, because paleontologists have long debated T. rex’s origins.
Finding T. rex's Origin
To better understand megaraptor mobility, the researchers created mathematical models drawing on the age and location of fossils, the dinosaur evolutionary tree, and climate information. They also accounted for gaps in the fossil record — important because relatively few megaraptors have been identified in Asia, while about 30 T. rex fossils have been discovered in North America.
“Our modelling suggests the ‘grandparents’ of T. rex likely came to North America from Asia, crossing the Bering Strait between what is now Siberia and Alaska,” Cassius Morrison, a graduate student at University College London and an author of the paper, said in a press release. “This is in line with past research finding that the T. rex was more closely related to Asian cousins such as the Tarbosaurus than to North American relatives such as Daspletosaurus."
Read More: Is the T. Rex Three Different Species?
Dinosaur Migration
The researchers connect dinosaur migration with climate change. They suspect that when the temperature peaked 92 million years ago, megaraptors went on the move. The researchers hypothesize that those dinosaurs were better suited to colder climates, maybe because they were covered in feathers or possessed a warm-blooded body.
However, that conclusion may not be universally accepted. The provenance of T. rex has, at times, provoked contentious debates within paleontology. For instance, a study in 2024 claimed that T. rex relative Tyrannosaurus mcraeensis, which was found in New Mexico, predated T. rex by 3 million to 5 million years.
The authors of that study say those findings support North American ancestry for T. rex. The authors of the new paper, however, disagree, saying that the T. mcraeensis fossil was dated incorrectly.
Until more megaraptor fossils are discovered outside North America, T. rex’s origin story may remain a mystery.
Read More: The T. Rex Was More Like a Smart Crocodile, Instead of a Bright Baboon
Article Sources
Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:
Royal Society Open Science. Rise of the king: Gondwanan origins and evolution of megaraptoran dinosaurs
Before joining Discover Magazine, Paul Smaglik spent over 20 years as a science journalist, specializing in U.S. life science policy and global scientific career issues. He began his career in newspapers, but switched to scientific magazines. His work has appeared in publications including Science News, Science, Nature, and Scientific American.
