европейская часть России

The Polyptycha sponges have been registered for the first time in the Upper Cretaceous beds from the Volga Region. The skeletons of those true colonies are peculiar for bushy morphotype complicated by anastomoses of the parent modules at their bending. The systematic position of the genus is disputable. This results from the incomplete understanding of the diverse skeleton morphologies in the Late Cretaceous hexactinellids and, correspondingly, from the lack of any standard criteria as regards the taxa of the “family” and the “genus” levels.

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.