New Study Traces Origins of Tyrannosaurus rex Back to Asia

In a groundbreaking study published in the journal Royal Society Open Science, researchers from University College London (UCL) have traced the origins of the famed Tyrannosaurus rex to Asia, suggesting that its ancestors crossed a land bridge to North America over 70 million years ago. This finding adds a significant chapter to the long-standing debate about the geographic origins of T. rex, which has divided paleontologists for years. Lead author Cassius Morrison, a PhD student at UCL's Earth Sciences department, asserts that the results from their mathematical modeling provide crucial evidence linking T. rex to its Asian origins via a migration across the Bering Strait. T. rex, one of the most iconic apex predators of the Late Cretaceous period, is primarily identified through fossils found in the U.S. states of Montana and South Dakota, alongside Alberta in Canada. The species lived approximately 67 to 66 million years ago and evolved into a dominating force across the region known as Laramidia, which stretched from present-day Alaska to Mexico. Interestingly, the researchers did not find a direct correlation between global temperature changes and increases in body mass for tyrannosaurids, suggesting that while cooler climates may have played a vital role in shaping the environments that allowed these giants to thrive, other ecological factors, like predator-prey dynamics, were likely significant contributors to their growth. Co-author Charlie Scherer highlights how climatic changes may have permitted the tyrannosaurs to reach unprecedented sizes as they filled niches left vacant by the extinction of competing giant predators, like carcharodontosaurids. The study also casts a light on megaraptors, another fascinating group of large theropod dinosaurs that thrived in the southern continents, known for utilizing elongated claws instead of powerful jaws. Dr. Mauro Aranciaga Rolando, another co-author, emphasizes that understanding the evolution and spread of megaraptors is equally crucial. Their ability to adapt to diverse environments across Gondwana – which once included regions like Australia and Patagonia – underscores their evolutionary success despite the scarcity of fossils. This research implies that the evolutionary adaptations of apex predators like T. rex and megaraptors reflect their responses to major climatic shifts, making the relationship between climate and evolutionary development an intriguing area for future exploration. Morrison urges further fossil discoveries in less-explored areas worldwide, particularly in regions of Africa and Antarctica, to fill gaps in our understanding of these magnificent creatures. The findings reset the narrative around T. rex’s ascent and hint at a complex interplay between climatic forces and biological evolution. It is a reminder that while we may uncover traces of the past, much of the dinosaurs' story remains woven into the fabric of unexplored lands. For subscribers interested in Earth sciences and paleontology, this study offers not only new insights into the timeline of these colossal predators but also ignites curiosity about the mysteries still buried within our planet’s layers.