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| Lobodiscus tribrachialis Zhao, Mussini, Y. Li, Tang, Vickers-Rich, M. Li & Chen, 2024 |
Highlights:
• The Jiangchuan biota of Yunnan preserves a late-Ediacaran eukaryotic assemblage
• We describe the first potential animal fossil from the Jiangchuan biota
• This new triradial fossil might represent the youngest known trilobozoan
• Our finding may strengthen taxonomic overlap among late-Ediacaran faunas
Summary
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.
Fossil geochemistry, Ecology, Evolutionary biology
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| Artistic reconstruction of Lobodiscus tribrachialis as a benthic metazoan-grade organism |
Systematic palaeontology
Genus Lobodiscus gen. nov.
Lobodiscus tribrachialis gen. et sp. nov.
Etymology: Lobo- from the Latin lobus, meaning lobe, -discus from the Latin discus, meaning disk, denoting the disc-like main body with radiating lobes; the species name combines the prefix tri- (from the Latin tres, three) and brachium, the Latin for “arm”, with reference to its 3-fold symmetry.
Mingsheng Zhao, Giovanni Mussini, Yulan Li, Feng Tang, Patricia Vickers-Rich, Ming Li and Ailin Chen. 2024. A putative triradial macrofossil from the Ediacaran Jiangchuan Biota. iScience. 27(2); 108823. DOI: doi.org/10.1016/j.isci.2024.108823 [16 February 2024]
