Dinosaurs once ruled Earth’s landscapes with diverse forms, including colossal plant-eaters like Argentinosaurus, fearsome predators like Tyrannosaurus, and peculiar species like Therizinosaurus, known for its elongated claws. However, the precise origin of dinosaurs—the time and place they first emerged—has remained elusive.
A new study suggests an unexpected region as the cradle of dinosaur evolution. This conclusion is drawn from the distribution of the earliest-known dinosaur fossils, their evolutionary traits, and the geological layout of Earth during the Triassic Period. Researchers propose that dinosaurs likely originated in the area now encompassing the modern-day Sahara Desert and the Amazon Rainforest. Though separated by vast distances and an ocean due to plate tectonics, these regions were part of a southern supercontinent called Gondwana during the dinosaurs’ emergence.
According to Joel Heath, a paleontology doctoral researcher from University College London and the Natural History Museum, dinosaurs first appeared in low-latitude zones near the equator within Gondwana, a region that today includes northern South America and northern Africa. The findings were published in the journal Current Biology.
The oldest dinosaur fossils, dating back approximately 230 million years, include Eoraptor and Herrerasaurus from Argentina, Saturnalia from Brazil, and Mbiresaurus from Zimbabwe. These species share distinct dinosaur characteristics while exhibiting enough variation to suggest millions of years of prior evolutionary history.
Previous studies have focused on southern South America and southern Africa as possible points of origin, but Heath argues that gaps in the fossil record—especially in the Sahara Desert and the Amazon Rainforest—could hold clues to where the earliest dinosaurs lived. These equatorial regions were extremely hot and arid during the late Triassic, featuring deserts, savannah-like terrains, and possibly seasonal wildfires.
The scarcity of fossils from this era may be due to unfavorable conditions for preservation or the challenging nature of exploration in these regions, where dense forests, expansive deserts, and logistical hurdles complicate research efforts.
Dinosaurs evolved from primitive reptiles following the Earth’s largest mass extinction approximately 252 million years ago, triggered by intense volcanic activity at the end of the Permian Period. Key skeletal adaptations set dinosaurs apart, such as upright limbs for efficient movement, specialized hips, and body structures designed for speed and agility.
For instance, Herrerasaurus, a predator about six meters long, and Eoraptor, a smaller omnivore, demonstrate the early traits of dinosaurs. These unique characteristics evolved gradually over millions of years from more primitive reptiles, but transitional fossils showing this evolutionary progression remain undiscovered.
Nyasasaurus, an enigmatic bipedal creature from Tanzania dating back roughly 240–245 million years, may resemble the earliest dinosaurs, though it is only known from incomplete remains.
In their early days, dinosaurs played a minor ecological role, overshadowed by dominant animals like large crocodile relatives, mammal-like herbivores, and armored reptiles. However, a mass extinction event around 201 million years ago eliminated many competitors, allowing dinosaurs to rise as the dominant land vertebrates.
