The stratigraphic distribution of irregular archaeocyaths (archaeocyathids) species in the Atdabanian Stage of the Altay-Sayan Foldbelt is established. One assemblage characterizes the Bazaikha Superhorizon and two assemblages are observed in the Kameshki Horizon. These assemblages are consistent independently of the facies type and traceable throughout Batenevskiy Ridge (carbonate facies), Tuva (volcanic-carbonate facies) and Eastern Sayan (siliciclastic-carbonate facies). This observation confirms the existence of a single Altay-Sayan basin by the middle Atdabanian time. Three new species (Loculicyathus voznesenskii, Mikhnocyathus irregularis, Sakhacyathus karpinskii) are described and the most typical species are revised and redescribed.
Archaeocyathida, Atdabanian, Altay-Sayan, correlations