TRIASSIC

252-201 MYA

The First of Dinosaurs, Era Ended with Mass Extinction

This extinction occurred just a few millennia before the breakup of the supercontinent of Pangaea. While its causes are not definitively understood—researchers have suggested climate change, an asteroid impact, or a spate of enormous volcanic eruptions as possible culprits—its effects are indisputable. More than a third of marine species vanished, as did most large amphibians of the time, as well as many species related to crocodiles and dinosaurs.