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| A life-scene from 232 million years ago, during the Carnian Pluvial Episode after which dinosaurs took over. A large rauisuchian lurks in the background, while two species of dinosaurs stand in the foreground. Based on data from the Ischigualasto Formation in Argentina. Summary of major extinction events through time, highlighting the new, Carnian Pluvial Episode at 233 million years ago. in Corso, Bernardi, Sun, ... et Benton, 2020. Illustration: Davide Bonadonna/ MUSE, Trento |
Abstract
The Carnian Pluvial Episode (Late Triassic) was a time of global environmental changes and possibly substantial coeval volcanism. The extent of the biological turnover in marine and terrestrial ecosystems is not well understood. Here, we present a meta-analysis of fossil data that suggests a substantial reduction in generic and species richness and the disappearance of 33% of marine genera. This crisis triggered major radiations. In the sea, the rise of the first scleractinian reefs and rock-forming calcareous nannofossils points to substantial changes in ocean chemistry. On land, there were major diversifications and originations of conifers, insects, dinosaurs, crocodiles, lizards, turtles, and mammals. Although there is uncertainty on the precise age of some of the recorded biological changes, these observations indicate that the Carnian Pluvial Episode was linked to a major extinction event and might have been the trigger of the spectacular radiation of many key groups that dominate modern ecosystems.
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| A life-scene from 232 million years ago, during the Carnian Pluvial Episode after which dinosaurs took over. A large rauisuchian lurks in the background, while two species of dinosaurs stand in the foreground. Based on data from the Ischigualasto Formation in Argentina. Illustration: Davide Bonadonna/ MUSE, Trento |
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| Summary of major extinction events through time, highlighting the new, Carnian Pluvial Episode at 233 million years ago. Illustration: Davide Bonadonna/ MUSE, Trento |
Jacopo Dal Corso, Massimo Bernardi, Yadong Sun, Haijun Song, Leyla J. Seyfullah, Nereo Preto, Piero Gianolla, Alastair Ruffell, Evelyn Kustatscher, Guido Roghi, Agostino Merico, Sönke Hohn, Alexander R. Schmidt, Andrea Marzoli, Robert J. Newton, Paul B. Wignall and Michael J. Benton. 2020. Extinction and Dawn of the Modern World in the Carnian (Late Triassic). Science Advances. 6(38): eaba0099. DOI: 10.1126/sciadv.aba0099
Newly discovered mass extinction event triggered the dawn of the dinosaurs
Adriana C. Mancuso, Cecilia A. Benavente, Randall B. Irmis and Roland Mundil. 2020. Evidence for the Carnian Pluvial Episode in Gondwana: New multiproxy climate records and their bearing on early dinosaur diversification. Gondwana Research. 86; 104-125. DOI: 10.1016/j.gr.2020.05.009
Abstract: Dinosaurs diversified in two steps during the Triassic. They originated about 245 Ma, during the recovery from the Permian-Triassic mass extinction, and then remained insignificant until they exploded in diversity and ecological importance during the Late Triassic. Hitherto, this Late Triassic explosion was poorly constrained and poorly dated. Here we provide evidence that it followed the Carnian Pluvial Episode (CPE), dated to 234–232 Ma, a time when climates switched from arid to humid and back to arid again. Our evidence comes from a combined analysis of skeletal evidence and footprint occurrences, and especially from the exquisitely dated ichnofaunas of the Italian Dolomites. These provide evidence of tetrapod faunal compositions through the Carnian and Norian, and show that dinosaur footprints appear exactly at the time of the CPE. We argue then that dinosaurs diversified explosively in the mid Carnian, at a time of major climate and floral change and the extinction of key herbivores, which the dinosaurs opportunistically replaced.
Massimo Bernardi, Piero Gianolla, Fabio Massimo Petti, Paolo Mietto and Michael J. Benton. 2018. Dinosaur Diversification linked with the Carnian Pluvial Episode. Nature Communications. 9: 1499 . DOI: 10.1038/s41467-018-03996-1