The discovery of Ahvaytum bahndooiveche, a 230-million-year-old dinosaur in Wyoming, reveals dinosaurs existed in the northern hemisphere earlier than believed, challenging past theories. When and how did dinosaurs first appear and spread across the planet over 200 million years ago?

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

"We think of dinosaurs as these giant behemoths, but they didn't start out that way." With a recent radioisotopic analysis of the fossil specimens dating the remains to around 230 million years old, this tiny 'terrible lizard' named Ahvaytum bahndooiveche is now the oldest-known dinosaur from Laurasia,