中国科学院南京地质古生物研究所机构知识库

The Weng'an Biota from the Ediacaran Doushantuo Formation in Guizhou Province, southwestern China, is known for its three-dimensionally phosphatized acritarchs, multicellular algae, and embryo-like animal fossils. Among these diverse microfossils, acanthomorphic acritarchs have played a significant role in the biostratigraphic subdivision and correlation of the lower-middle Ediacaran System. However, most previous studies on the biostratigraphy of the Doushantuo Formation in the Weng'an area have focused on large acanthomorphic acritarchs (LAAs, vesicle diameter >200 mu m), whereas the smaller acanthomorphic acritarchs (SAAs, vesicle diameter <100 mu m) from the Weng'an Biota have been largely overlooked. In this study, we examined >500 thin sections and discovered a large number of well-preserved, small (<100 mu m) and medium-sized acanthomorphic acritarchs (MAAs, vesicle diameter ranging 100-200 mu m). In total, we have identified SAAs in four genera and six species (Tanarium conoideum Kolosova, 1991, emend. Moczyd & lstrok;owska et al., 1993; Tanarium elegans Liu et al., 2014; Mengeosphaera membranifera Shang, Liu, and Moczyd & lstrok;owska, 2019; Mengeosphaera minima Liu et al., 2014; Estrella recta Liu and Moczyd & lstrok;owska, 2019; Variomargosphaeridium gracile Xiao et al., 2014), as well as two types of MAAs (Tanarium tuberosum Moczyd & lstrok;owska, Vidal, and Rudavskaya, 1993, emend. Moczyd & lstrok;owska, 2015; Weissiella cf. W. grandistella Vorob'eva, Sergeev, and Knoll, 2009, emend. Liu and Moczyd & lstrok;owska, 2019). This updated acritarch assemblage of the Weng'an Biota is valuable for correlating the Ediacaran Doushantuo Formation between the Weng'an and Yangtze Gorges areas. It also serves as a tool to test the proposed acritarch biozones in Ediacaran formations of South China and other localities, including Australia, Siberia, and the East European Platform.