Seven species occur in shallow-marine limestone of the Sete Lagoas Formation, Bambuí Group, in Januária, Brazil, including Siphonophycus robustum, Leiosphaeridia crassa, Leiosphaeridia jacutica, Leiosphaeridia minutissima, Leiosphaeridia tenuissima, Germinosphaera bispinosa, and a new species named Ghoshia januarensis. In the lower part of the studied section, these occurrences are common, but only Ghoshia januarensis is found in the upper part. This is likely due to changes in the environment or preservation conditions. The Leiosphaeridia species, especially Leiosphaeridia minutissima, dominates the assemblage of organic-walled microfossils. While most described taxa have long stratigraphic ranges, they are consistent with a terminal Ediacaran age, as indicated by detrital zircon data and tubular fossils (e.g., Cloudina and Corumbella) from the Sete Lagoas Formation.

This work presents a detailed taxonomic study on organic-walled microfossils from the Ediacaran Sete Lagoas Formation (Bambuí Group) at the Barreiro section in the Januária area of the São Francisco basin, Brazil. Seven species are described, including Siphonophycus robustum (Schopf, 1968), Ghoshia januarensis new species, Leiosphaeridia crassa (Naumova, 1949), Leiosphaeridia jacutica (Timofeev, 1966), Leiosphaeridia minutissima (Naumova, 1949), Leiosphaeridia tenuissima Eisenack, 1958, and Germinosphaera bispinosa Mikhailova, 1986. These taxa are recovered for the first time in the Sete Lagoas Formation. They occur abundantly in the lower portion of the studied section, but only Ghoshia januarensis is present in the upper part of the studied section, probably due to environmental or taphonomic changes. Leiosphaeridia species, particularly Leiosphaeridia minutissima, dominate the organic-walled microfossil assemblage. Although most taxa described here have long stratigraphic ranges, they are consistent with a terminal Ediacaran age as inferred from detrital zircon data and tubular fossils (e.g., Cloudina and Corumbella) from the Sete Lagoas Formation.