Extinction and dawn of the modern world in the Carnian (Late Triassic)

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.

Paleozoic–Mesozoic Eustatic Changes and Mass Extinctions: New Insights from Event Interpretation

“…The other extinction event occurred in the Carnian Stage of the Late Triassic [ 53 ]. This biotic perturbation was reported very recently, but the arguments in favor of its existence are really strong.…”

“…Moreover, better understanding of biotic crises, their magnitude, and precise timing is desirable. For instance, the only very recent discovery of the Carnian catastrophe [ 53 ] implies how incomplete the knowledge of mass extinctions can be even for such well-studied geologic time intervals as the Mesozoic.…”

Description of the metoposauridAnaschisma brownifrom the New Oxford Formation of Pennsylvania

“…A large body of recent work has emerged examining the role of the Carnian Pluvial Episode (CPE) in shaping terrestrial tetrapod evolution, but few have explicitly addressed temnospondyls. Buffa et al (2019) and Fortuny et al (2019) suggested a correlation between metoposaurid diversification and the CPE, which has been increasingly linked to major events of Triassic tetrapod evolution (e.g., Simms and Ruffell, 1989, 1990; Ruffell et al, 2016; Dal Corso et al, 2020), particularly to the radiation of dinosaurs (e.g., Benton et al, 2018; Bernardi et al, 2018; Mancuso et al, 2020). However, as those workers also noted, it remains to be tested how this climate event would have favored some clades of large-bodied stereospondyls over others; most studies remain focused on amniotes.…”

The Upper Triassic Polzberg palaeobiota from a marine Konservat-Lagerstätte deposited during the Carnian Pluvial Episode in Austria

“…The dry Middle and Upper Triassic climate was interrupted by a middle Carnian global phase of increased humidity in the western Tethys and hence in Europe. This episode is characterised by a worldwide decrease of platform inhabitants and reef demise known as the Carnian Pluvial/Humid Episode (CPE 19 , 20 , 41 – 43 ). The episode was a longer and multi-phased process rather than a single event 44 .…”