56-2 The Proterozoic Biosphere through Time and Space

Session: Phylogenetic and Computational Approaches in Paleobiology and Paleoecology, Part II

Presenting Author:

Sanaa Mughal

Authors:

Mughal, Sanaa¹, Jouault, Corentin², Cribb, Alison Taveau³, Stockey, Richard G.⁴, Saupe, Erin⁵, Anderson, Ross Peter⁶, Konhauser, Kurt O.⁷

(1) Department of Earth & Atmospheric Sciences, University of Alberta, Edmonton, AB, Canada, (2) Oxford University Museum of Natural History, University of Oxford, Oxford, United Kingdom, (3) School of Ocean & Earth Science, University of Southampton, Southampton, Hampshire, United Kingdom, (4) School of Ocean and Earth Science, University of Southampton, Southampton, United Kingdom, (5) Department of Earth Sciences, University of Oxford, Oxford, United Kingdom, (6) Oxford University Museum of Natural History, University of Oxford, Oxford, United Kingdom, (7) Department of Earth & Atmospheric Sciences, University of Alberta, Edmonton, AB, Canada,

Abstract:

Quantifying macroevolutionary patterns using fossil data can untangle the complex interplay between biological innovation, speciation, extinction, and ecosystem structure, all within the context of Earth’s shifting atmosphere, oceans, and land across deep time. Yet the scarcity and often poor preservation of the Precambrian fossil record pose major challenges for reconstructing early evolutionary trajectories. Previous studies have identified broad trends in Precambrian biodiversity, suggesting a Paleoproterozoic origin of eukaryotes, a relatively stable Mesoproterozoic, and a dynamic Neoproterozoic marked by environmental upheavals such as global oxygenation and ‘Snowball Earth’ glaciations. However, these previous studies have focused almost exclusively on the eukaryotic fossil record, leaving the relationship between prokaryotes and eukaryotes comparatively unexplored. Here, we present results from a comprehensive new database, compiling over 2,000 occurrences of both eukaryotic and prokaryotic microfossils reported in the literature from successions 2.1 and 0.54 Ga. We estimate patterns of diversity and diversification rates in time and space primarily using the PyRate toolkit, with a focus on patterns of fossil occurrences by paleogeographical and depositional environment. We further examine microbial community composition by exploring co-occurrence patterns of species with respect to assemblages through time. Our spatio-temporal study ensures a comprehensive reconnaissance of the Proterozoic biosphere as currently documented through the lens of the microfossil record. This synthesis not only captures diversity and community shifts by geological age and paleoenvironment, but it also serves as a template for investigating future evolutionary questions.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

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