~201 million years agoReputable sourceWell documented
The End-Triassic Extinction
On the timeline · around ~201 million years ago · The Jurassic
What happened
A mass extinction around 201 million years ago — one of the 'big five' — wiped out up to 80% of species. It was probably driven by enormous volcanism (the Central Atlantic Magmatic Province) as the supercontinent Pangaea began to rift apart, and it killed off many of the archosaurs that had competed with dinosaurs.
Why it matters
With their rivals gone, dinosaurs inherited a nearly empty world. They diversified explosively in the Jurassic and became the dominant land animals for the next ~135 million years.
Sources
- Natural History Museum. The Triassic Period: the rise of the dinosaurs · Reputable source