Triassic Period
251 - 199.6 million years ago
Dinosaur Encyclopedia (By Period)
Index by Period
Many dinosaurs once roamed the Earth.
They first appeared about 230 million years ago and disappeared about 66 million years ago.
New species are discovered every year, and it's estimated there were about 1,500 species in total.
Let's learn about these creatures we call 'dinosaurs.'
Here is a list organized by the Triassic, Jurassic, and Cretaceous periods.
