A putative triradial macrofossil from the Ediacaran Jiangchuan Biota

Mingsheng Zhao; Giovanni Mussini; Yulan Li; Feng Tang; Patricia Vickers-Rich; Ming Li; Ailin Chen

doi:10.1016/j.isci.2024.108823

A putative triradial macrofossil from the Ediacaran Jiangchuan Biota

iScience. 2024 Jan 9;27(2):108823. doi: 10.1016/j.isci.2024.108823. eCollection 2024 Feb 16.

Authors

Mingsheng Zhao¹, Giovanni Mussini², Yulan Li³, Feng Tang⁴, Patricia Vickers-Rich^{5

6}, Ming Li⁴, Ailin Chen⁷

Affiliations

¹ College of Paleontology, Shenyang Normal University, Shenyang 110034, China.
² Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ, UK.
³ 111 Geological Brigade, Guizhou Bureau of Geology and Mineral Resources, Guiyang 550081, China.
⁴ Key Laboratory for Stratigraphy and Palaeontology, MNRC, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China.
⁵ School of Earth, Atmosphere and Environment, Monash University, Melbourne, VIC 3800, Australia.
⁶ Department of Chemistry, Chemistry and Resources precinct, Curtin University, Perth, WA 6845, Australia.
⁷ Research Center of Paleobiology, Yuxi Normal University, Yuxi 653100, China.

Abstract

The late Ediacaran Jiangchuan biota, from the Dengying Formation in eastern Yunnan, is well-known for its diverse macroalgal fossils, opening a window onto eukaryotic-dominated ecosystems from the late Neoproterozoic of South China. Although multiple lines of evidence suggest that metazoans had already evolved by the late Ediacaran, animal fossils have not yet been formally described from this locality. Here, we report a putative disc-shaped macrofossil from the Jiangchuan biota, Lobodiscus tribrachialis gen. et sp. nov. This specimen shows the triradial symmetry characteristic of trilobozoans, a group of Ediacaran macrofossils previously documented in Australia and Russia. Lobodiscus could record the youngest known occurrence of trilobozoans, strengthening taxonomic and ecological continuities between the Ediacaran "White Sea" and "Nama" assemblages. Our findings may expand the known paleogeographical distribution of trilobozoans and provide data for Ediacaran biostratigraphic correlations across the Yangtze block and globally, helping to track the diversification of early metazoan-grade organisms.

Keywords: Ecology; Evolutionary biology; Fossil geochemistry.