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A new study challenges the idea that the earliest dinosaurs roamed the Amazon and other parts of South America. UCL researchers Joel Heath and Philip Mannion propose that the first dinosaurs likely originated in hotter, drier regions within what was once Gondwana—a supercontinent covering parts of Africa, the Amazon, and the Sahara Desert today. Their findings suggest that the earliest known dinosaur fossils might be found in equatorial areas of this region rather than the southernmost parts of South America or Africa.
The study published in *Current Biology* used modeling to account for missing pieces in the fossil record. This approach indicated that the earliest dinosaurs may have emerged around 230 million years ago, long before previously believed dates. Heath explained that current dinosaur fossils were found in more southerly regions because of incomplete data, not because they evolved further south.
The researchers identified that early dinosaurs were small, bipedal creatures—likely omnivores—with traits similar to today’s crocodilians and theropods. However, over millions of years, theropods (like T rex) and ornithischians (including Eoraptor) developed body heat generation, allowing them to thrive in colder regions like the poles.
Among the earliest known dinosaurs are species such as Eoraptor, Herrerasaurus, Coelophysis, and Eodromaeus. The study highlights that Gondwana’s warm, equatorial regions may have been pivotal in the evolution of these early reptiles, setting the stage for the diverse ecosystems we see today.
Source: https://www.ucl.ac.uk/news/2025/jan/new-twist-mystery-dinosaurs-origin