Distribution of Ediacaran acanthomorphic acritarchs in the lower Doushantuo Formation of the Yangtze Gorges area, South China: Evolutionary and stratigraphic implications

As part of the most common eukaryotic fossils in early Ediacaran strata, acanthomorphic acritarchs are crucial for understanding biostratigraphy and evolutionary dynamics marine eukaryotes after Marinoan global glaciation. Abundant diverse have been reported from Doushantuo Formation Yangtze Gorges area, South China, different biozonation schemes proposed. However, these previously published biozones were based on biostratigraphic data compiled stratigraphic sections, with little effort to test whether can be consistently recognized at despite fact that regional consistency is critical a robust framework. Also, pattern has not documented detail, especially lowermost Formation, largely due perceived low taxonomic richness In this study, we report silicified other microfossils chert nodules lower (Member II) Jiulongwan, Jinguadun, Wuzhishan sections area. From total 1547 acritarch specimens found, 24 genera 69 species identified, including two new (Annularidens gen. nov. Crassimembrana nov.), six inconditus et sp. nov., Bispinosphaera vacua crispans C. multitunica Distosphaera jinguadunensis Mengeosphaera matryoshkaformis five unnamed sp., 1, 2, Sinosphaera Variomargosphaeridium sp.), three possible forms tentatively placed open nomenclatures (Crassimembrana cf. crispans, Tanarium T. conoideum, Weissiella W. grandistella). The high-resolution fossil occurrence abundance reveal both spatial variations composition, similarities acanthomorph range abundance, indicating taxa applied subdivision correlation only if their records thoroughly investigated least scale. FADs (first appearance data) such as Appendisphaera grandis, heliaca n. comb., Ericiasphaera fibrilla, Tianzhushania spinosa, well relative certain taxa, promising markers Formation. also rapid diversification eukaryotes, acanthomorphs increasing notable levels within probably ten million years termination glaciation, followed by continuing increase evenness afterwards.