The Triassic–Jurassic (Tr-J) extinction event (TJME), often called the end-Triassic extinction, was a Mesozoic extinction event that marks the boundary between the Triassic and Jurassic periods, 201.4 million years ago,[a] and is one of the top five major extinction events of the Phanerozoic eon,[2] profoundly affecting life on land and in the oceans. In the seas, the entire class of conodonts[3][4] and 23–34% of marine genera disappeared.[5][6] On land, all archosauromorphs other than crocodylomorphs, pterosaurs, and non-avian dinosaurs became extinct; some of the groups which died out were previously abundant, such as aetosaurs, phytosaurs, and rauisuchids. Some remaining non-mammalian therapsids and many of the large temnospondyl amphibians had become extinct prior to the Jurassic as well. However, there is still much uncertainty regarding a connection between the Tr-J boundary and terrestrial vertebrates, due to a lack of terrestrial fossils from the Rhaetian (uppermost) stage of the Triassic.[7] Plants, crocodylomorphs, dinosaurs, pterosaurs and mammals were left largely untouched;[8][9][10] this allowed the dinosaurs, pterosaurs, and crocodylomorphs to become the dominant land animals for the next 135 million years.[11][9]