Acritarchs from the Doushantuo Formation at Liujing section in Songlin area of Guizhou Province, South China: Implications for early-middle Ediacaran biostratigraphy

A taxonomically diverse and morphologically disparate microfossil assemblage is recovered from the upper Doushantuo Formation in the Liujing section of Songlin area, Guizhou Province, including acanthomorphic and sphaeromorphic acritarchs, multicellular algae, and filamentous cyanobacteria. Acritarch Mengeosphaera membranifera sp. nov. is newly erected and genus Cymatiosphaeroides and several species (C. forabilatus, C. kullingii, Bacatisphaera baokangensis) are emended in the systematics. The acanthomorphic species are dominated by Cymatiosphaeroides forabilatus and Mengeosphaera membranifera sp. nov. The Liujing assemblage shares many species with other Ediacaran coeval assemblages from South China, Australia, Siberia, the East European Platform, India, Mongolia and Svalbard, and indicates a significant taxonomic similarity to the global, agediagnostic assemblages. New occurrence of those known taxa in the Liujing succession documents the biodiversity of the Ediacaran acritarchs in South China. The Liujing assemblage extends the palaeogeographic distribution of the Ediacaran acritarchs and may be assigned to the Tanarium conoideum-Cavospina basiconica Assemblage Zone that was recognized in the Yangtze Gorges area of South China. Alternatively, it could be partially correlated with the barren interval between T. conoideum-C. basiconica Assemblage Zone and the overlying Tanarium pycnacanthum-Ceratosphaeridium glaberosum Assemblage Zone.