ABSTRACT
The modern loss of species diversity has been labelled the ‘sixth extinction’ subsequent to the five major mass extinctions widely recognised in the Phanerozoic geologic record – the end-Ordovician (443.8 Ma), the Late Devonian (372.2 Ma), end-Permian (251.9 Ma), end-Triassic (201.4 Ma) and end-Cretaceous (66 Ma) events. Rankings in terms of numbers of genera suffering extinction, and especially in terms of ecological impact, however, put the end-Guadalupian (end-Capitanian) (259.8 Ma) extinction event in the same category with the other major mass extinctions. Thus, there were apparently six major Phanerozoic mass extinctions, and the current loss of species should perhaps be called the ‘seventh extinction’.
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Acknowledgments
We thank K. Caldeira, A. Melott and an anonymous reviewer for helpful comments.
Disclosure statement
No potential conflict of interest was reported by the authors.