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How were sharks and bony fishes affected by 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.

By the end of the Permian Period, both sharks and bony fishes experienced significant population declines as part of the broader mass extinction event.1

While these groups survived the crisis, their diversity was notably reduced. For instance, chondrichthyan fishes (the group including sharks), which had reached a peak of radiation and flowering during the Carboniferous Period, became greatly diminished by the end of the Permian. They remained at these reduced levels of diversity until the Jurassic Period, when environmental conditions in the seas became more favorable for their recovery and subsequent diversification.2

The Permian extinction was a period of profound biological loss that affected a wide range of aquatic and terrestrial life, including amphibians, therapsids, and various invertebrates, ultimately reshaping the composition of marine ecosystems.1