A multiscale view of the Phanerozoic fossil record reveals the three major biotic transitions

Abstract

The hypothesis of the Great Evolutionary Faunas is a foundational concept of macroevolutionary research postulating that three global mega-assemblages have dominated Phanerozoic oceans following abrupt biotic transitions. Empirical estimates of this large-scale pattern depend on several methodological decisions and are based on approaches unable to capture multiscale dynamics of the underlying Earth-Life System. Combining a multilayer network representation of fossil data with a multilevel clustering that eliminates the subjectivity inherent to distance-based approaches, we demonstrate that Phanerozoic oceans sequentially harbored four global benthic mega-assemblages. Shifts in dominance patterns among these global marine mega-assemblages were abrupt (end-Cambrian 494 Ma; end-Permian 252 Ma) or protracted (mid-Cretaceous 129 Ma), and represent the three major biotic transitions in Earth’s history. Our findings suggest that gradual ecological changes associated with the Mesozoic Marine Revolution triggered a protracted biotic transition comparable in magnitude to the end-Permian transition initiated by the most severe biotic crisis of the past 500 million years. Overall, our study supports the notion that both long-term ecological changes and major geological events have played crucial roles in shaping the mega-assemblages that dominated Phanerozoic oceans.

A Bizarre Planthopper Nymph (Hemiptera: Fulgoroidea) from Mid-Cretaceous Kachin Amber

“…The Burma Terrane, in which the amber occurs, was part of a Trans-Tethyan island arc at a near-equatorial more-southern latitude at about 95 million years ago, suggesting island endemism for the Kachin amber biota [15]. The Kachin amber is still giving us new insights into the very important period of formation of modern faunistic complexes during the mid-Cretaceous biotic re-organization [21] and provides ideal material for studying the Cretaceous Terrestrial Revolution, which is marked by the radiation of angiosperms, social insects, and mammals [22][23][24][25]. Radiometric U-Pb zircon dating of the volcaniclastic matrix of the amber constrained a refined age of 98.79 ± 0.62 million years ago (earliest Cenomanian) [26].…”

Increase in marine provinciality over the last 250 million years governed more by climate change than plate tectonics

“…Large-scale fossil provinces were demarcated following Kocsis et al [23,24] as described in the electronic supplementary material, text. Such network approaches have been previously described to be efficient in highlighting community changes across the Phanerozoic [33,34], and they were previously documented to be effective in defining modules that represent time-traceable biogeographic units (hereafter: provinces) for occurrences of recent benthic marine animals during the last 10 Myr [24].…”

Bottom-up controls, ecological revolutions and diversification in the oceans through time

“…Chaetognaths, predaceous fish and other nektonic groups originated before the Devonian, so arguably the mid-Paleozoic ecosystem change was too incremental to be called a 'revolution' 87 . In recent network analyses and machine learning classifications, the Ediacaran-Cambrian radiation, GOBE and Mesozoic marine revolution stand out for evolutionary radiations, while the Devonian does not 88,89 . Assuming some amount of ecotypic and evolutionary turnover did occur in the Devonian, bottom-up mechanisms might have contributed to this restructuring.…”