The oldest equatorial dinosaur in the world, and North America's oldest dinosaur, has been described in a new study. Dating back 230 million years, the chicken-sized dinosaur has big implications for our understanding of how dinosaurs spread across the world,

This discovery challenges the long-held belief that dinosaurs originated exclusively in the southern supercontinent, Gondwana.

Researchers discovered Ahvaytum bahndooiveche fossils in Wyoming, revealing dinosaurs in Laurasia earlier than believed.

How and when did dinosaurs first emerge and spread across the planet more than 200 million years ago? That question has for decades been a source of debate among paleontologists faced with fragmented fossil records.