The area where dinosaurs, the former owners of the Earth, first appeared has become more likely to change. Until now, paleontologists believed dinosaurs emerged in the Southern Hemisphere, but recent research findings contradict this view.
A research team led by Joel Heath, a professor at the University of London, announced on the 23rd (local time) that contrary to previous beliefs, dinosaurs evolved in the Amazon rainforest near the equator.
Paleontologists estimate that dinosaurs first appeared on Earth between 200.1 million and 252 million years ago. The oldest dinosaur fossil is about 230 million years old and was discovered in the mid-latitude regions of the Southern Hemisphere, where present-day Argentina and Zimbabwe are located. Based on this evidence, experts have believed that the area where dinosaurs first appeared was also in the Southern Hemisphere.
However, some paleontologists speculate that dinosaurs may have actually been living on Earth prior to that time. If this hypothesis is true, it is highly likely that the area where dinosaurs first appeared is different from the Southern Hemisphere.
The research team developed a computer model to investigate the timing and location of dinosaur evolution. The computer model was created in dozens of versions, taking into account the timing of the dinosaur fossil formation and geographical influences.
As a result, the majority of simulations concluded that dinosaurs appeared near the equator rather than in the Southern Hemisphere. Professor Heath noted, "The paleontological community has a preconception that dinosaurs could not have originated near the equator," adding, "This belief stems from the absence of dinosaur fossils found near the equator and the perception that it would be too dry and hot for dinosaurs to live there."
The research team pointed out that the reason dinosaur fossils have not been found near the equator is that investigations have not been conducted there. Paleontologists primarily excavate dinosaur fossils in the Northern Hemisphere, focusing on areas such as North America, Europe, and China. There have been very few cases of excavation in the equatorial region.
Professor Heath explained, "There are still quite a few neglected areas of the Earth where dinosaur fossils have not yet been discovered," and stated, "In the vicinity of the equator, the geological layers from the time when dinosaurs lived are not exposed, so no research has been conducted there."
Recently, dinosaur fossils supporting the research team's hypothesis have also been discovered. On the 8th, researchers at the University of Wisconsin-Madison found dinosaur fossils approximately 230 million years old in the state of Wyoming. The North American continent was part of the geography located in the Northern Hemisphere of Pangaea when all continents were connected in the past. Since dinosaur fossils have been found in both the Southern and Northern Hemispheres of Pangaea around the same time, it is no longer assured that the location where dinosaurs first appeared is in the Southern Hemisphere.
Professor Heath stated, "If dinosaur fossils have been discovered in both the Northern and Southern Hemispheres when dinosaurs first appeared, the possibility that dinosaurs did not inhabit the areas near the equator is greatly reduced," adding, "Dinosaurs likely traversed the equator between the Northern and Southern Hemispheres as well."
The research findings were introduced in the international academic journal Current Biology on the 23rd.
Reference materials
Current Biology (2025), DOI: https://doi.org/10.1016/j.cub.2024.12.053
Zoological Journal (2025), DOI: https://doi.org/10.1093/zoolinnean/zlae153