Cited by 1,010Evolution and Paleontology StudiesPaleontology and Stratigraphy of FossilsPaleontology and Evolutionary Biology

A factor analytic description of the Phanerozoic marine fossil record

Sepkoski, J. John·1981·Paleobiology

Abstract

Data on numbers of marine families within 91 metazoan classes known from the Phanerozoic fossil record are analyzed. The distribution of the 2800 fossil families among the classes is very uneven, with most belonging to a small minority of classes. Similarly, the stratigraphic distribution of the classes is very uneven, with most first appearing early in the Paleozoic and with many of the smaller classes becoming extinct before the end of that era. However, despite this unevenness, a Q -mode factor analysis indicates that the structure of these data is rather simple. Only three factors are needed to account for more than 90% of the data. These factors are interpreted as reflecting the three great “evolutionary faunas” of the Phanerozoic marine record: a trilobite-dominated Cambrian fauna, a brachiopod-dominated later Paleozoic fauna, and a mollusc-dominated Mesozoic-Cenozoic, or “modern,” fauna. Lesser factors relate to slow taxonomic turnover within the major faunas through time and to unique aspects of particular taxa and times. Each of the three major faunas seems to have its own characteristic diversity so that its expansion or contraction appears as being intimately associated with a particular phase in the history of total marine diversity. The Cambrian fauna expands rapidly during the Early Cambrian radiations and maintains dominance during the Middle to Late Cambrian “equilibrium.” The Paleozoic fauna then ascends to dominance during the Ordovician radiations, which increase diversity dramatically; this new fauna then maintains dominance throughout the long interval of apparent equilibrium that lasts until the end of the Paleozoic Era. The modern fauna, which slowly increases in importance during the Paleozoic Era, quickly rises to dominance with the Late Permian extinctions and maintains that status during the general rise in diversity to the apparent maximum in the Neogene. The increase in diversity associated with the expansion of each new fauna appears to coincide with an approximately exponential decline of the previously dominant fauna, suggesting possible displacement of each evolutionary fauna by its successor.

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Crossref · 10.1017/s0094837300003778

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  • There is well-documented covariation between Phanerozoic metazoan macroevolutionary patterns and sedimentary rock availability.

    “there is a well-documented covariation between Phanerozoic metazoan macroevolutionary patterns and sedimentary rock availability [e.g., (8)]”

    From Sea level controls on Ediacaran-Cambrian animal radiations (2024) · cites this paper as [8]

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Authors
Sepkoski, J. J.
Affiliations
University of Chicago (US)
Corresponding author
Sepkoski, J. John
Venue
Paleobiology
Published
1981
Volume
7
Issue
1
Pages
36-53
ISSN
  • 0094-8373 (ISSN-L)
  • 1938-5331
OpenAlex
W2505144080
Cited by
1,010
References
2
Citations by year
2026: 35 · 2025: 49 · 2024: 29 · 2023: 57 · 2022: 43 · 2021: 38 · 2020: 41 · 2019: 48 · 2018: 38 · 2017: 38 · 2016: 40 · 2015: 42 · 2014: 24 · 2013: 22 · 2012: 38
FWCI
20.96
Type
journal article
Language
en
Open access
closed
Locations
Paleobiology (publishedVersion)
Topics
  • Physical Sciences › Earth and Planetary Sciences › Paleontology › Evolution and Paleontology Studies
  • Physical Sciences › Earth and Planetary Sciences › Paleontology › Paleontology and Stratigraphy of Fossils
  • Physical Sciences › Earth and Planetary Sciences › Paleontology › Paleontology and Evolutionary Biology
Keywords
trilobites, brachiopods, Mollusca, Cambrian explosion, Ordovician radiation, end-Permian mass extinction, taxonomic turnover

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