Where did dinosaurs first evolve? Scientists have an answer

Dinosaurs likely originated in the low-latitude regions of Gondwana near the equator, evolving over millions of years.

Dinosaurs long dominated the earth’s land ecosystems with multiple forms, including plant-eating giants like Argentinosaurus, meat-eating brutes like Tyrannosaurus, and weirdos like Therizinosaurus, with its Wolverine-like claws.

But the origin of dinosaurs — precisely when and where they first appeared — remains a bit of a puzzle.

Researchers are now proposing a surprising location for the birthplace of dinosaurs, based on the locations of the currently oldest-known dinosaur fossils, the evolutionary relationships among these early forms, and the earth’s geography during the Triassic Period.

This locale spans the modern-day Sahara desert and Amazon rainforest regions, now separated by thousands of kilometres and an ocean thanks to a geological process called plate tectonics.

“When dinosaurs first appear in the fossil record, all the earth’s continents were part of the giant supercontinent Pangaea. Dinosaurs emerged in the southern portion of this landmass, known as Gondwana,” said Joel Heath, a paleontology doctoral student at University College London and the Natural History Museum in London and lead author of the study, published on Thursday in the journal Current Biology.

“Our research suggests they likely originated in the low-latitude regions of Gondwana near the equator, an area that today includes northern South America and northern Africa,” Heath added.

The earliest-known dinosaur fossils date to roughly 230 million years ago, including Eoraptor and Herrerasaurus from Argentina, Saturnalia from southern Brazil, and Mbiresaurus from Zimbabwe. While sharing certain traits defining them as dinosaurs, they had sufficient differences that suggest millions of years of dinosaur evolution had already occurred.