The rise of modern-type entomofauna in the Triassic

Insects are the major contributor of Earth’s biodiversity, as the most diverse group in the modern biosphere. Considerable debates on the timing of entomofauna modernization remain, but most recent studies indicate it could have happened during the Triassic, following the “Great Dying” across the Permian–Triassic boundary. Using global insect diversity data and fossil records of select representative faunas, we performed computational analysis and comparative research to explore the compositional dynamics of entomofauna in the Permian and Triassic. Our analysis shows that: 1) following the Permian–Triassic mass extinction, insect diversity rapidly increased in the Anisian Stage of the Middle Triassic; 2) modern-dominating orders, such as Coleoptera, Diptera, Hymenoptera, Hemiptera, and Orthoptera exceeded half of the total diversity in the Ladinian; 3) In the Carnian of the Late Triassic, Coleoptera had emerged to be the dominating group of the entomofauna. These findings indicate that the rise of modern-typed entomofauna can be traced back to the Ladinian–Carnian (late Middle Triassic–early Late Triassic), much earlier than the Cretaceous Terrestrial Revolution.