Late Triassic
75 genera
The first dinosaurs were small and quick. Bigger reptiles still ruled. The oldest names in this book sit here.
Open the dinosaurs from this timeDeep time
When they lived
These dinosaurs lived from about 230 million years ago until 66 million years ago. Most of the names are from the Cretaceous, because those rocks are easier to find. If a dinosaur crossed from one time into the next, it is counted in both.
Early Jurassic
94 genera
A big extinction cleared the stage. Dinosaurs spread into more jobs, including early long-necks and meat-eaters.
Open the dinosaurs from this timeMiddle Jurassic
120 genera
Fewer fossils turned up, but the familiar shapes are already here, including huge long-necked plant-eaters.
Open the dinosaurs from this timeLate Jurassic
176 genera
Stegosaurus time, plus Allosaurus and the classic long-necks. A lot of famous skeletons come from rocks this old.
Open the dinosaurs from this timeEarly Cretaceous
353 genera
Feathered hunters show up in lake mud. Armored plant-eaters spread. Flowering plants begin.
Open the dinosaurs from this timeLate Cretaceous
691 genera
The busiest chapter: horned dinosaurs, duckbills, and tyrannosaurs. An asteroid ended it 66 million years ago.
Open the dinosaurs from this time