Evolution of paleobiocommunities is one of the most intractable problems of biostratigraphy

The biostratigraphic material accumulated to date on the subdivision of the Phanerozoic marine strata allows us to decipher the features of the evolution of not only low biota taxa, but also paleocommunities (assemblages), which can be considered as biotic groupings historically formed under certain conditions. Examples of the stages of their evolution in various marine ecosystems of Geomerida are given. The opinion is expressed about the need to intensify research on this topic with the involvement of both geologists and biologists.