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Dinosaurs may have first evolved near the modern-day Sahara and Amazon rainforest regions of what was once a giant supercontinent called Gondwana. A study published in *Current Biology* identifies these areas as the likely birthplaces of the earliest dinosaurs, which began to appear around 230 million years ago.
These early dinosaur fossils, including Eoraptor and Herrerasaurus from Argentina, Saturnalia from Brazil, and Mbiresaurus from Zimbabwe, were found in regions that were once part of Gondwana’s equatorial low-latitude areas. This suggests that the birthplace of dinosaurs was not limited to just one region but spanned across today’s modern-day Sahara Desert and Amazon rainforest, which were separated by an ocean due to plate tectonics.
The researchers propose that these early dinosaurs likely emerged approximately 245-230 million years ago when these regions were extremely hot and dry, with environments ranging from deserts to forested areas prone to wildfires. Heath explained that the conditions may have been challenging for fossilization but remain an area of active research.
Dinosaurs evolved from more primitive reptiles after a major mass extinction event about 252 million years ago, triggered by volcanic activity at the end of the Permian Period. Heath emphasized that while their unique upright bodies and specialized skeletal structures made them faster and more agile than other reptiles, the exact evolutionary path remains a mystery due to the scarcity of transitional fossils.
Hearasaurus, an enigmatic bipedal creature from Tanzania, may provide some clues about what these early dinosaurs looked like, based on fragmentary fossils. Dinosaurs initially dominated Earth alongside other large predators and plant-eaters, but their gradual evolution and resilience allowed them to overshadow competitors and eventually dominate the land ecosystems of the Triassic Period.
This groundbreaking research offers new insights into the origins of life on Earth and highlights the importance of studying ancient fossils to understand our shared ancestry with these fascinating creatures.
Source: https://www.reuters.com/science/where-did-dinosaurs-first-evolve-scientists-have-an-answer-2025-01-23