Rising sea levels may have helped dinosaurs dominate the planet

By Michael Marshall

MAURICIO ANTON / SCIENCE PHOTO LIBRARY

Vast floods caused by sea level rise may have helped dinosaurs take over the planet.

The first dinosaurs evolved early in the Triassic period, about 245 million years ago, but these were rare. It took about another 20 million years before they came to dominate land ecosystems. Palaeontologists are unsure why the dinosaurs came to be so numerous and diverse, while other reptile groups like crocodiles did not.

In 2019, researchers led by Tore Klausen, then at the University of Bergen in Norway, reported that in the late …