Morpho-functional innovations in Shibantan fossils fuel Ediacaran frond debates

Abstract

The Ediacara biota represents Earth’s earliest complex macroscopic organisms, but their biology and ecology remain poorly understood. Here we report Dengyingia pennata gen. et sp. nov., an exceptionally preserved frondose fossil from the late Ediacaran ( ~550–543 Ma) Shibantan limestone of South China. Dengyingia possesses a unique body plan: a bifoliate petalodium of unconstrained, flexible primary branches with pronounced two-sided differentiation—a smooth obverse surface and a reverse surface covered by secondary and tertiary modules. This innovation represents a key morphological advance among Ediacaran fronds. Its architecture, basal growth pattern, and suspension-feeding strategy align with those of modern sea pens (pennatulacean cnidarians), reflecting adaptations for dynamic filter-feeding in currents. Dengyingia bridges the ecological gap between the Ediacara biota and Phanerozoic suspension-feeding animals, demonstrating that complex, animal-like ecological strategies emerged before the Cambrian explosion. These findings expand Ediacaran diversity and provide insights into early animal functional differentiation. An exceptionally preserved Ediacaran frond, Dengyingia pennata, from South China shows a unique branched body plan and functional convergence with modern sea pens, suggesting complex suspension-feeding strategies evolved prior to the Cambrian diversification.