The Upper Triassic is the last epoch in the Triassic period. It began 237 million years ago, and ended 201.3 million years ago. It came after the Middle Triassic epoch, and came before the Lower Jurassic epoch.
The other two epochs of the Triassic were the Lower Triassic epoch and the Middle Triassic epoch.
Many early dinosaur species appeared for the first time during the Upper Triassic, including Plateosaurus, Coelophysis, and Eoraptor. Pterosaurs were common in the air, and Ichthyosaurs dominated the seas.
At the end of the Upper Triassic some event or events caused the extinction of many animal species worldwide. Known as the end–Triassic extinction event, it was similar to the more famous event that lead to the extinction of the dinosaurs, except no one knows for sure what caused the event. There are many theories as to what caused the event such as meteorite impact, tsunamis, or coronal mass ejections from the sun.