Triassic Period

Permian Period - Triassic Period - Jurassic Period

The Triassic Period is the first period of the Mesozoic Era, and the seventh of the Phanerozoic Eon. The Triassic begins with the Permian-Triassic extinction event, the largest in the planet's history, and ends with the Triassic-Jurassix extinction event.

The supercontinent of Pangaea remained mostly intact throughout the period, while the Tethys Ocean began to emerge, replacing the Paleo-Tethys. The vast ocean on Panthalassa engulfed most of the planet's saltwater.

Life began to re-diversify following the tragic extinction that marked the beginning of the period and the new era. Pachypleurosaurs and Nothosaurs both became quite common, primarily in the Tethys and Paleo-Tethys oceans. Placodonts lived exclusively during the Triassic, and the first Plesiosaurs evolved during the period as well. The Thalattosaurs would not survive into the Jurassic, though the Ichthyosaurs survived well into the Cretaceous. Fish diversification took a longer amount of time to commence, and the paraphyletic group was remarkably uniform during the period.

The Triassic, and the Mesozoic as a whole for that matter, is best known for the first dinosaurs and pterosaurs, though neither were the most significant development as far as terrestrial fauna is concerned. Mammals first appeared in the fossil record during the Triassic period, and survived to the present day, while neither the (non-Avian) dinosaurs nor the pterosaurs were able to. The oldest dinosaurs evolved in the Middle and Late Triassic epochs. Nyasasaurus may be the oldest known dinosaur, or may be a close relative. Known from 243 MYA, it predates the previously oldest known dinosaurs by approximately 12 million years. Dinosaurs were far from being dominant species during the Triassic, as they were rivaled by mammal-like reptiles and other groups. Mostly small in size during the period, the dinosaurs would use that trait to their advantage in surviving the extinction at the end of the period, positioning themselves to rise to dominance in the Jurassic.

The Triassic is subdivided into three epochs: the Early Triassic, the Middle Triassic, and the Late Triassic.

Triassic Timescale:

Triassic Period - 251.902-201.36 MYA

-Early Triassic Epoch - 251.902-246.8 MYA

--Induan Age - 251.902-249.8 MYA

--Olenekian Age - 249.8-246.8 MYA

-Middle Triassic Epoch - 246.8-235 MYA

--Anisian Age - 246.8-241.5 MYA

--Ladinian Age - 241.5-235 MYA

-Late Triassic Epoch - 235-201.36 MYA

--Carnian Age - 237-228.4 MYA

--Norian Age - 228.4-209.5 MYA

--Rhaetian Age - 209.5-201.36 MYA