Dinosaurs first appeared during the Triassic period, approximately between 243 and 233 million years ago. The earliest known dinosaurs emerged after the largest mass extinction event around 252 million years ago that wiped out many species. Fossils found in regions that are now part of South America and Africa suggest that dinosaurs originated in the southern part of the supercontinent Pangaea, particularly in low-latitude areas near the equator such as today's northern South America and northern Africa. The earliest dinosaurs were small, bipedal predators, evolving gradually over millions of years before becoming dominant terrestrial vertebrates about 200 million years ago after a significant extinction event.