~230 million years agoReputable sourceWell documented
The First Dinosaurs
On the timeline · around ~230 million years ago · Mesozoic
What happened
The oldest known dinosaurs — small, agile predators such as Eoraptor and Herrerasaurus — appeared in the Late Triassic, around 230 million years ago, in what is now South America.
Why it matters
From these modest beginnings, dinosaurs would rise to dominate the land for around 165 million years, one of the most successful groups of animals in Earth's history.
Sources
- Natural History Museum. The Triassic Period: the rise of the dinosaurs · Reputable source