New bryozoan species from the stratotype section of the Upper Kazanian Substage

Representatives of nine bryozoan genera of four orders are identified for the first time from the carbonate deposits of the stratotype section of the Upper Kazanian Substage of the Middle Permian. Among them four new species are established and described: Permopora volgensis sp. nov., Stellahexaformis burovi sp. nov., Alternifenestella esaulovae sp. nov., and Wjatkella definita sp. nov. A brief lithological characterization is provided of the carbonate deposits that contain the remains of these bryozoans and were formed under the conditions of transgression-regression cycles of the Late Kazanian marine basin. Some questions concerning the taphonomy, ecology, and morphology of the bryozoans studied are considered.