Plio-Pleistocene environmental variability in Africa and its implications for mammalian evolution

Andrew S. Cohen*, Andrew Du, John Rowan, Chad L. Yost, Anne L. Billingsley, Christopher J. Campisano, Erik T. Brown, Alan L. Deino, Craig S. Feibel, Katharine Grant, John D. Kingston, Rachel L. Lupien, Veronica Muiruri, R. Bernhart Owen, Kaye E. Reed, James Russell, Mona Stockhecke

*Corresponding author for this work

    Research output: Contribution to journalJournal articlepeer-review

    12 Citations (Scopus)

    Abstract

    Understanding the climatic drivers of environmental variability (EV) during the Plio- Pleistocene and EV's influence on mammalian macroevolution are two outstanding foci of research in African paleoclimatology and evolutionary biology. The potential effects of EV are especially relevant for testing the variability selection hypothesis, which predicts a positive relationship between EV and speciation and extinction rates in fossil mammals. Addressing these questions is stymied, however, by 1) a lack of multiple comparable EV records of sufficient temporal resolution and duration, and 2) the incompleteness of the mammalian fossil record. Here, we first compile a composite history of Pan-African EV spanning the Plio-Pleistocene, which allows us to explore which climatic variables influenced EV. We find that EV exhibits 1) a long-term trend of increasing variability since ∼3.7 Ma, coincident with rising variability in global ice volume and sea surface temperatures around Africa, and 2) a 400-ky frequency correlated with seasonal insolation variability. We then estimate speciation and extinction rates for fossil mammals from eastern Africa using a method that accounts for sampling variation. We find no statistically significant relationship between EV and estimated speciation or extinction rates across multiple spatial scales. These findings are inconsistent with the variability selection hypothesis as applied to macroevolutionary processes.

    Original languageEnglish
    Article numbere2107393119
    Number of pages7
    JournalProceedings of the National Academy of Sciences of the United States of America
    Volume119
    Issue number16
    DOIs
    Publication statusPublished - 19 Apr 2022

    Scopus Subject Areas

    • General

    User-Defined Keywords

    • Africa
    • mammalian evolution
    • paleoclimate
    • Plio-Pleistocene
    • variability selection

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