When did the first dinosaurs appear in relation to the Permian extinction?

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Line graph showing the number of marine animal families from the Precambrian era to the present, with illustrations of key groups such as trilobites, ammonoids, marine reptiles, and diatoms. The graph highlights major extinction events and a rise to 1,900 living families today. — Permian extinction The diversity of marine animal families since late Precambrian time. The data for the curve comprise only those families that are reliably preserved in the fossil record; the 1,900 value for living families also includes those families rarely preserved as fossils. The several pronounced dips in the curve correspond to major mass-extinction events. The most catastrophic extinction took place at the end of the Permian Period.

The first dinosaurs appeared during the Triassic Period, which followed the Permian extinction.1

The Permian extinction, the largest mass extinction in Earth's history, occurred at the end of the Permian Period, roughly 252 million years ago. Dinosaurs did not exist during the Permian; rather, they emerged during the recovery of life that took place in the Triassic Period. While the exact timing of the first "true dinosaurs" is difficult to pinpoint due to gaps in the fossil record, they evolved from ancestral archosaurs during the Triassic.2314