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Early Palaeozoic diversifications and extinctions in the marine biosphere: a continuum of change

Harper, David A.T.; Cascales-Miñana, Borja; Servais, Thomas

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David A.T. Harper

Borja Cascales-Miñana

Thomas Servais


A review of biodiversity curves of marine organisms indicates that, despite fluctuations in amplitude (some large), a large-scale, long-term radiation of life took place during the early Palaeozoic Era; it was aggregated by a succession of more discrete and regionalized radiations across geographies and within phylogenies. This major biodiversification within the marine biosphere started during late Precambrian time and was only finally interrupted in the Devonian Period. It includes both the Cambrian Explosion and the Great Ordovician Biodiversification Event. The establishment of modern marine ecosystems took place during a continuous chronology of the successive establishment of organisms and their ecological communities, developed during the ‘Cambrian substrate revolution’, the ‘Ordovician plankton revolution’, the ‘Ordovician substrate revolution’, the ‘Ordovician bioerosion revolution’ and the ‘Devonian nekton revolution’. At smaller scales, different regional but important radiations can be recognized geographically and some of them have been identified and named (e.g. those associated with the ‘Richmondian Invasion’ during Late Ordovician time in Laurentia and the contemporaneous ‘Boda event’ in parts of Europe and North Africa), in particular from areas that were in or moved towards lower latitudes, allowing high levels of speciation on epicontintental seas during these intervals. The datasets remain incomplete for many other geographical areas, but also for particular time intervals (e.g. during the late Cambrian ‘Furongian Gap’). The early Palaeozoic biodiversification therefore appears to be a long-term process, modulated by bursts in significant diversity and intervals of inadequate data, where its progressive character will become increasingly clearer with the availability of more complete datasets, with better global coverage and more advanced analytical techniques.


Harper, D. A., Cascales-Miñana, B., & Servais, T. (2020). Early Palaeozoic diversifications and extinctions in the marine biosphere: a continuum of change. Geological Magazine, 157, 5-21.

Journal Article Type Article
Acceptance Date Sep 30, 2019
Online Publication Date Dec 3, 2019
Publication Date Jan 31, 2020
Deposit Date Dec 14, 2019
Publicly Available Date Jun 3, 2020
Journal Geological Magazine
Print ISSN 0016-7568
Electronic ISSN 1469-5081
Publisher Cambridge University Press
Peer Reviewed Peer Reviewed
Volume 157
Pages 5-21


Accepted Journal Article (9.7 Mb)

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Copyright Statement
This article has been published in a revised form in Geological magazine This version is published under a Creative Commons CC-BY-NC-ND. No commercial re-distribution or re-use allowed. Derivative works cannot be distributed. © Cambridge University Press 2019.

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