Biostratigraphy of Upper Devonian sections in the western Altai-Sayany region based on bryozoans

The analysis of characteristic bryozoan assemblages from Upper Devonian sections of the western Altai-Sayany region made it possible to define the following biostratigraphic units: lower Frasnian Leioclema vassinense, upper Frasnian Petalotrypa bifoliata, basal Famennian Leioclema numerosum, upper lower Famennian Megacanthopora glubokaensis, upper middle Famennian Eridocampylus striatum-Atactotoechus cellatus, and upper Famennian Monotrypa carbonica-Pseudobatostomella longipora beds. Six bryozoans species from type Frasnian assemblages of the western Altai-Sayany folded region are also recorded in the Nakhichevan Republic (Transcaucasia region) and Kazakhstan, while 11 Famennian species from the study region are known in Mongolia, the eastern Transbaikal region, Kazakhstan, China, and the South Urals.