тафономия

Paleogeographic reconstructions of sedimentation settings have been substantially refined from the taphonomic data from the ichthyofauna localities; the Permian fishes from East Europe have lately acquired the orthostratigraphic status. The taphonomic research in a number of the Middle and the Late Permian ichthyofauna locations has largely confirmed the reality of existence of fairly extensive sedimentation basins over European Russia in the Kazanian, the Urzhumian and the Severodvinian ages; those basins used to be periodically connected with the World Ocean. 

The examination of the modular organization in fossil skeletal sponges (Hexactinellida) is mainly related to a study of their vegetative reproduction. The concepts of the reproductive forms for both Recent and Mesozoic hexactinellids can be ambiguous. Examples of the skeletons of fossil sponges from the Late Cretaceous of the Volga River basin, with morphologically detached and naturally distributed sprouts interpreted as buds, are shown. 

The paper analyzes the taxonomic composition and the habitat of the representatives of the Middle – Late Cenomanian and the Middle Turonian marine biota. The examined fossils have been isolated from the bulk sample obtained from the phosphorite horizon lying in the bottom of the Middle Turonian carbonate rocks in the Senomanskaya Stenka section (Volgograd Region, Zhirnovsk district).