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The Mesozoic Era [3] is the era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceous Periods.It is characterized by the dominance of gymnosperms such as cycads, ginkgoaceae and araucarian conifers, and of archosaurian reptiles such as the dinosaurs; a hot greenhouse climate; and the tectonic break-up of Pangaea.
The Triassic is the first and shortest period of the Mesozoic Era and the seventh period of the Phanerozoic Eon. Both the start and end of the period are marked by major extinction events. [10] The Triassic Period is subdivided into three epochs: Early Triassic, Middle Triassic and Late Triassic.
c. 251.9 Ma ± 0.024 Ma – Mesozoic era and Triassic Period begin. Mesozoic Marine Revolution begins. c. 245 Ma – First ichthyosaurs. c. 240 Ma – Cynodonts and rhynchosaurs diversify. c. 225 Ma – First dinosaurs and teleosti evolve. c. 220 Ma – First crocodilians and flies. c. 215 Ma – First turtles.
During the end-Triassic extinction, 46%–72% of all marine genera became extinct. The effects of the end Triassic extinction were greatest at tropical latitudes and were more severe in Panthalassa than the Tethys or Boreal oceans. Tropical reef ecosystems collapsed during the event, and would not fully recover until much later in the Jurassic.
Several temnospondyl groups did become extinct near the end of the Triassic despite earlier abundance, but it is uncertain how close their extinctions were to the end of the Triassic. The last known metoposaurids (" Apachesaurus ") were from the Redonda Formation , which may have been early Rhaetian or late Norian .
Many evolutionary changes occurred at this stage: eyelids and tear glands evolved to keep the eyes wet out of water and the eyes became connected to the pharynx for draining the liquid; the hyomandibula (now called columella) shrank into the spiracle, which now also connected to the inner ear at one side and the pharynx at another, becoming the ...
Permian–Triassic boundary at Frazer Beach in New South Wales, with the End Permian extinction event located just above the coal layer [2]. Approximately 251.9 million years ago, the Permian–Triassic (P–T, P–Tr) extinction event (PTME; also known as the Late Permian extinction event, [3] the Latest Permian extinction event, [4] the End-Permian extinction event, [5] [6] and colloquially ...
Life colonized the land, first plants, then animals. Two significant extinctions occurred. The continents formed at the break-up of Pannotia and Rodinia at the end of the Proterozoic slowly moved together again, forming the supercontinent Pangaea in the late Paleozoic. [148] The Mesozoic ("middle life") era lasted from 251.9 Ma to 66 Ma. [105]