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Britannica Sources used in this answer

When did trilobites disappear from Earth’s fossil record?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
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.

Trilobites, a group of marine arthropods that first appeared during the Cambrian Period, made their final appearance in the fossil record during the Permian Period. They disappeared at the end of the Permian, coinciding with the massive Permian-Triassic extinction event, which resulted in the loss of a vast majority of marine invertebrate species.12