Chitinozoans in the Wenlock-Ludlow boundary beds of the East Baltic

Abstract

The distribution of chitinozoans in the Wenlock-Ludlow boundary beds was studied in five drill core sections of the East Baltic. It was established that most of the typical Wenlock chitinozoan species became extinct in the uppermost part of the Jaagarahu Stage. In the lower part of the Rootsikilla Stage the Sphaerochitina lycoperdoides Biozone was identified for the first time. The Conochitina postarmillata and Ancyrochitina desmea biozones were established in the Dubysa Formation of the Paadla Stage in the Ventspils and Pavilosta cores and in the Gorstian Stage of the Gussev-1 core. Two stratigraphically important new species, Rhabdochitina sera and Conochitina postarmillata, were described, and Eisenackitina lagena (Eisenack) was redescribed.