Main changes in microfossil communities throughout the Upper Proterozoic of Russia

More than 50 years of study have resulted in the description of hundreds of taxa of Precambrian microfossils from the different regions of Russia. These forms are usually preserved either as silicified or organic-walled remains and generally are morphologically simple and stratigraphically long-ranging. The systematics of Precambrian microorganisms still needs a serious revision, although efforts by specialists from all over the world to solve these problems have helped to clarify the biological assignment of some taxa.