Том: 29 , Уear of publication: 2021

The results of micropaleontological analysis of the boundary interval of the lowermiddle Callovian in the TETs-5 section (Saratov) are presented. The taxonomic composition and distribution of foraminifera and ostracods in the section are studied. The ranges of the biostratigraphic units inferred from microfauna and their correlation with the ammonite scale are refined. Two foraminiferal zones of the East European Platform are established: Haplophragmoides infracalloviensisGuttulina tatarensis and Lenticulina cultratiformisLenticulina pseudocrassa. The volume of the Lenticulina cultratiformisLenticulina pseudocrassa Zone ranges from the upper part of the lower Callovian (the upper part of the Koenigi Zone and the Calloviense Zone) to the middle Callovian. Two biostratigraphic units by ostracods are established: (1) the Acantocythere milanovskyiProcytheridea cinicinnusa Zone corresponding to the Subpatruus Zone of the lower Callovian, to the lower part of the Ch. saratovensis biohorizon, and (2) Beds with Praeschuleridea wartaePleurocythere kurskensis corresponding to the terminal part of the Subpatruus Zone (the upper part of the Ch. saratovensis biohorizon), the Koenigi and Calloviense zones of the lower Callovian, and the lower part of the Jason Zone of the middle Callovian. The images of typical taxa are provided.