中国科学院南京地质古生物研究所机构知识库

Abundant sphaeroidal acritarch Leiosphaeridia asperata, with vesicle size ranging from 13 to 360 mu m, occurred in the Proterozoic Liulaobei Formation shales in Huainan, Anhui Province. TEM/SEM studies of these sphaeroidal acritarchs have revealed complex ultrastructures, including ridges, bands, and possible trilaminar structures (TLS). Ridges, spaced similar to 1 mu m apart, are distributed regularly on the vesicle internal surface of one specimen. Some specimens have alternating electron-dense and electron-tenuous bands that are perpendicular to vesicle walls. Some specimens have trilaminar structures (TLS), while a few others have both bands and TLS. These wall ultrastructures provide evidence that the Liulaobei leiosphaerids are of green microalgae. The variation in wall ultrastructures may represent various stages in a life cycle or developmental phases in the cyst formation analogous to some modern chlorophyceaen microalgae.