175-5 Evolutionary biotas of Proterozoic eukaryotes

Session: The Neoproterozoic Earth and Life Co-evolution, Part I

Presenting Author:

Qing Tang

Authors:

Tang, Qing¹, Zhang, Shuhan², Zheng, Wentao³, Wang, Jiayue⁴, Xue, Lang⁵, Chu, Tianyi⁶, Fan, Junxuan⁷, Zhang, Feifei⁸, Shi, Yukun⁹, Wang, Xiangdong¹⁰, Zhao, Guochun¹¹, Shen, Shuzhong¹², Xiao, Shuhai¹³

(1) Nanjing University, Nanjing, Jiangsu, China, (2) Nanjing University, Nanjing, Jiangsu, China, (3) Department of Earth Science, University of California, Santa Barbara, Santa Barbara, CA, USA, (4) Nanjing University, Nanjing, Jiangsu, China, (5) Nanjing University, Nanjing, Jiangsu, China, (6) Nanjing University, Nanjing, Jiangsu, China, (7) Nanjing University, Nanjing, Jiangsu, China, (8) Nanjing University, Nanjing, Jiangsu, China, (9) Nanjing University, Nanjing, Jiangsu, China, (10) Nanjing University, Nanjing, Jiangsu, China, (11) University of Hong Kong, Hong Kong, Hong Kong SAR, China; Northwest University, Xi'an, China, (12) Nanjing University, Nanjing, China, (13) Virginia Tech, Blacksburg, VA, USA,

Abstract:

Evolutionary ecological investigation of the fossil record provides key insights into the macroevolution of life and its interactions with the environment. While numerous Proterozoic eukaryote fossils have been documented in the past decades, few studies have quantitatively examined the coordinated changes in space and time. This is largely due to the difficulty of integrating scattered Proterozoic fossil records into a high-resolution temporal framework. To address this knowledge gap, we compiled a Proterozoic database integrating paleontological, sedimentological, geochemical, and geochronological data from 263 fossiliferous sections worldwide. We applied the Constrained Optimization (CONOP) method of quantitative stratigraphy to build a best-fit composite sequence for all studied eukaryotic taxa. The stratigraphic range of each taxon was then calculated based on the intercalated radiometric ages in the composite sequence. Subsequently, the community overlap propagation algorithm (COPRA) was employed to detect evolutionary biotas (analogous to Sepkoski’s evolutionary faunas in the Phanerozoic) and their dynamics within a high-resolution temporal framework. The results reveal that Proterozoic eukaryotes form three distinct evolutionary biotas. The earliest evolutionary biota mainly consists of organic-walled microfossils, vase-shaped microfossils, and phosphatized scales in the pre-Cryogenian Proterozoic. The succeeding evolutionary biota is dominated by Doushantuo-Pertatataka acritarchs and macroalgae in the early (pre-Gaskiers) Ediacaran. The final evolutionary biota mainly comprises animal body and trace fossils in the late Ediacaran. These evolutionary biotas indicate two first-order evolutionary-ecological transitions: from simple microorganisms to morphologically complex eukaryotes, and subsequently to macroscopic animals. Additionally, these evolutionary-ecological transitions temporally coincide with major ice ages—the Cryogenian glaciations and Ediacaran Gaskiers glaciation—suggesting an intriguing relationship between Proterozoic eukaryote evolution and environmental perturbations.

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

doi: 10.1130/abs/2025AM-11046

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