Paleogeographically, South China was located near the equator during Late Ordovician–early Silurian. Well developed graptolite
zones and shelly fauna of upper Ordovician successions in South China correlate well with those from Katian and Hirnantian successions
elsewhere in the world. We report here acritarch assemblages from the Katian black shales of the Wufeng Formation in the Lingfeng coal
section, southeastern Sichuan, and from the Hirnantian carbonate rocks of the Kuanyinchiao Formation in the Yanzikou section of
northwestern Guizhou and the Huanggexi section of northeastern Yunnan. This study provides the first description and biostratigraphic
data of the acritarch assemblage of the Hirnantian Kuanyinchiao Formation in South China, and enables the interpretation of paleogeographic
and paleoenvironmental changes during the major glaciation of the latest Ordovician in South China. These acritarch assemblages
represent the microphytoplanktonic communities of preglacial, Hirnantian glacial and postglacial in South China. Two new
species, Multiplicisphaeridium pugnusum n. sp., and Perissolagonella irregular n. sp., are described.