The Mesozoic era lasted from 251.9 to 66 million years ago, divided into the Triassic, Jurassic and Cretaceous periods. Dinosaurs rose to dominate life on land, and the first mammals, birds and flowering plants appeared.
Pangaea slowly broke apart and the modern oceans began to open, and the era ended when an asteroid struck what is now Mexico, at Chicxulub, and most dinosaur lineages disappeared.
Explore this era on the timeline
Key events of the Mesozoic
15 events are on the timeline for this era; these are among the most notable, in date order.
- about 252 million years agoPermian-Triassic mass extinction
- about 233 million years agoEarliest known dinosaurs
- about 225 million years agoThe first mammals appear
- about 210 million years agoFirst flying reptiles (pterosaurs)
- about 205 million years agoFirst mammals
- about 201 million years agoTriassic-Jurassic mass extinction
- about 200 million years agoPangaea begins to break apart
- about 183 million years agoToarcian turnover
- about 150 million years agoArchaeopteryx, the earliest known bird, lives in Jurassic Bavaria
- about 150 million years agoFirst birds
- from about 130 million years ago to 89 million years agoGallic epoch
- about 130 million years agoFlowering plants spread
- about 116 million years agoAptian extinction
- about 93.9 million years agoCenomanian-Turonian boundary event
- about 66 million years agoCretaceous-Paleogene mass extinction