The Triassic–Jurassic extinction event marks the boundary between the Triassic and Jurassic periods, , and is one of the major extinction events of the Phanerozoic eon, profoundly affecting life on land and in the oceans. In the seas, a whole class (conodonts) and 34% of marine genera disappeared. On land, all pseudosuchians (non-dinosaurian archosaurs) other than crocodylomorphs (Sphenosuchia and Crocodyliformes), some remaining therapsids, and many of the large amphibians became extinct.