Where Did the T. rex Come From? Paleontologists Think They’ve Finally Figured It Out

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The fossils of the Tyrant Lizard (T. rex), often referred to as the queen of dinosaurs, are discovered solely in North America. Interestingly, these giants share more similarities with large Asian theropod dinosaids than they do with their carnivorous counterparts from the U.S. and Canada.

A recently published study in the journal “Royal Society Open Science” could potentially explain why T. rex, famously depicted in Universal’s “Jurassic Park” and “Jurassic World” movies, developed as it did. By examining fossils and tracing the evolutionary history of T. rex and related dinosaur families, paleontologists propose that T. rex actually originated on North American soil, but its ancestors are believed to have migrated from Asia approximately 70 million years ago.

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Tracing the origins of Tyrannosaurus rex

Scholars discussing the potential origins, are split between suggesting that the immediate forebears of T-Rex hail from North America or Asia. A recent investigation spearheaded by a doctoral student at University College London named Cassius Morrison might finally put this debate to rest.

According to researcher Cassius Morrison, speaking through the Natural History Museum in London, our analysis implies that the ancestors of T. rex probably made their way to North America from Asia, crossing over what is now the Bering Strait between Siberia and Alaska. This aligns with previous studies suggesting that T. rex was more closely related to Asian relatives like its cousin species, rather than North American counterparts such as Daspletosaurus. Our results hint that while numerous T. rex fossils have been discovered in North America, the fossils of its immediate ancestors could potentially still be hidden in Asia.

90 million years back, our world held a distinct appearance compared to today. Fast forward 250 million years, and all Earth’s landmasses were united as one giant supercontinent known as Pangaea. This colossal landmass started fragmenting around 200 million years ago, splitting into two major continents – Laurasia in the north and Gondwanaland in the south. By the Cretaceous period (144 – 66 million years ago), our modern continents were already separated but still closely packed together. North America itself was divided into two distinct continents, Laramidia in the west and Appalachia in the east, with the Western Interior Seaway acting as a bridge between them. Travel across these landmasses back then was simpler than it is today.

In simpler terms, the forerunners of Tyrannosaurs – extinct now – were much smaller than their well-known successors. Some were similar in size to a medium-sized dog, while others could fit comfortably on your shoulders. It wasn’t until around 90 million years ago that these small creatures began growing bigger, as the larger carcharodontosaurid theropods became extinct. This vacancy in the ecosystem allowed Tyrannosaurs to evolve from their smaller ancestors into the dominant predators of the Late Cretaceous period.

During approximately the same epoch, when the carcharodontosaurids became extinct, Earth was experiencing a phase of swift cooling. The planet had reached its hottest point in global temperatures, called the Cretaceous Thermal Maximum, around 92 million years back, but temperatures started to decline thereafter. Tyrannosaurids and a group of large predators known as megaraptors survived this period, primarily because they were adapted to colder climates and grew to immense sizes to occupy the void left behind.

According to Charlie Scherer, who is affiliated with University College London, our research reveals insights into the emergence of colossal tyrannosaurs in North and South America during the Cretaceous period. Furthermore, it sheds light on how and why these dinosaurs grew to such immense sizes towards the end of the dinosaur era, as reported by Sci News.

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2025-05-08 23:51