What were the first dinosaurs?

The first period in which dinosaurs lived in was the triassic, starting about 251 mya (million years ago) and ender about 200 mya. The carnivores in this time period were small, like the Coelophysis, and Eoraptor. But the Herbivores were huge, like the Plateosaurus.

The Eoraptor, Coelophysis and Plateosaurus were a few of the first Dinosaurs.