Rhetian
Rhetian is a term used in geology to describe a geological period that occurred during the Mesozoic era, specifically within the Triassic period. The Rhetian stage is the second stage of the Triassic period, following the Induan and preceding the Norian. It spanned from approximately 208.5 million years ago to about 201.3 million years ago. The Rhetian is characterized by significant geological and biological changes, including the development of new marine ecosystems and the diversification of early reptiles. This period is also notable for the extinction event at the end of the Triassic, known as the Triassic-Jurassic extinction event, which marked the end of the Triassic period and the beginning of the Jurassic period. The Rhetian stage is named after the Rhaetian Alps, a mountain range in Switzerland, where the first Rhetian fossils were discovered.