中国科学院南京地质古生物研究所机构知识库

Polybessurus, as a common element of the late Mesoproterozoic to early Neoproterozoic microfossil assemblages, has yet no confirmed record from post-Cryogenian strata. In this study, we report Polybessurus sp. from the Ediacaran Doushantuo Formation chert nodules in western Hubei Province, South China. Polybessurus specimens from the Doushantuo Formation are identical to their preCryogenian counterparts in morphology (stacked concave lamellae), composition (organic matter), and preservational mode (silicification). The Doushantuo specimens generally have large tubes (average diameter -157 lm, maximum diameter -450 lm), and are often preserved separately and parallel to the bedding plane, whereas the pre-Cryogenian specimens have relatively small tubes (mostly thinner than 100 lm in diameter), and are often preserved gregariously and perpendicular to the bedding plane. Polybessurus may be formed by a variety of benthic micro-organisms, mainly cyanobacteria, e.g., stalk forming taxa like Cyanostylon and endolithic taxa like Solentia, that are capable of secreting EPS (extracellular polymeric substance) unidirectionally to push itself forward in the sediment. The producers of Polybessurus may have played a role in the benthic microbial community by making microburrows, affecting textures and microenvironments of inshore sediments. As the first unambiguous record of Polybessurus from Ediacaran strata, our new findings extend its distribution from the late Mesoproterozoic-early Neoproterozoic to the late Neoproterozoic. (c) 2021 Elsevier B.V. and Nanjing Institute of Geology and Palaeontology, CAS. All rights reserved.