Researchers Amazed to Find Out T. Rex. Dinosaurs Evolved in North America 70 Million Years Ago
Dinosaurs have long vanished from Earth, but they are still objects of huge interest for researchers. Tyrannosaurus rex, especially, has been a source of huge debate, specifically regarding its origins, according to Phys.org. A recent study published in Royal Society Open Science describes a model that could possibly put this debate to rest and provides more insights about this creature's evolution.
The model showcases that T. rex evolved primarily in North America, but their ancestors were from Asia. For years, scientists have been divided on the continent where T. rex originated, the model provides a clear answer. According to the study, these ancestors likely came to North America through a land bridge that connected both continents 70 million years ago. Another important detail revealed by the model was that both T. rex and its close relative, megaraptors, experienced considerable growth during a cooling period the Earth experienced 92 million years ago.
The mathematical model was created by a team from University College London, or UCL, according to CNN. It was led by Cassius Morrison, a doctoral student of paleontology. This model took into account the existing fossil record of the dinosaur and all the data available about the T. rex family tree. The data set contained information like climatic and environmental factors needed for each of the species in the family tree to survive. Researchers ensured that the model accounted for gaps in the records. This guarantees that new developments in the record at later times can be incorporated.
The finding aligns with past examinations, which claimed that T. rex was more similar to the large Asian carnivore Tarbosaurus than North American predators like Daspletosaurus. Researchers believe that there are no fossil records of T. rex ancestors, tyrannosaurids in Asia, because they were less in number. Seventy million years ago, Asia contained temperate rainforests and had a climate similar to present-day British Columbia. In this habitat, tyrannosaurids were like lions, apex predators, lower in quantity than their prey, which in this case were herbivorous dinosaurs. Experts are hopeful that some fossils possibly survived and could resurface at a certain point in time.
After arriving in North America, T. rex underwent evolution and widely spread across Laramidia, the western half of the continent, during the Late Cretaceous period, according to The Jerusalem Post. Researchers have uncovered fossils in places like the U.S. states of Montana and South Dakota, as well as Alberta in Canada. Evolution played a huge role in their growth, reaching 12.5 feet tall at the hips and up to 41 feet long in size.
The model indicates that T. rex and their cousins, megaraptors, reached garangutan sizes due to the Earth's cooling experienced after the Cretaceous Thermal Maximum (CTM), 92 million years ago. Temperatures fell sharply and created a climate that was better suited for T. rex than its rival dinosaur groups. The competitors went extinct, which removed the 'ecological barrier' that was in front of T. rex, in terms of growth. A similar phenomenon helped megaraptors. "It was easier to be big when temperatures were cool. The kings of the dinosaurs were not predestined to rule but were helped along by the climate," said Steve Brusatte, a paleontologist at the University of Edinburgh.