Graptolites from the rhuddanian-aeronian boundary interval (Silurian), prague synform, czech republic

Abstract

Forty-five graptolite species belonging to nineteen genera collected from loose rocks in the field at Všeradice and assigned to the upper vesiculosus, cyphus, triangulatus and lower pectinatus biozones of late Rhuddanian and early Hj Aeronian age are described and discussed. Of 16 species recorded for the first time in the Czech Republic, five species are new (Normalograptus parvus, Normalograptus frydai, Glyptograptus perneri, Pseudorthograptus mitchelli and Pernerograptus pribyli); eight species are left in open nomenclature. The generic diagnoses of Pseudorthograptus Legrand, Demirastrites Eisel and Pernerograptus Přibyl are emended. The sedimentary and faunal succession in the Všeradice area is reconstructed by correlation with the biostratigraphically well dated graptolite-rich sections elsewhere on the southern limb of the Prague Synform.