Early Ordovician bryozoans from north-western Russia

A bryozoan assemblage from the Billingen Stage of north-western Russia (Ing ria) is apparently the oldest known in the world. It consists of six specie s distributed among the trepostomate genera Esthoniopora, Dianulites, Reval otrypa, Phragmophora and Hemiphragma. Two species are new: Phragmophora lav aense Pushkin, sp. nov, and Hemiphragma priscum Pushkin, sp. nov. The bryoz oans are characteristic of the medium diversity benthic fauna of uncertain origin which migrated into the Baltic Basin during Billingen time (late Pri oniodus elegans-early Oepikodus evae zones). The Billingen bryozoans have a close similarity to the late Arenig bryozoan faunas of Baltoscandia that a n also dominated by trepostomates, but differ significantly from the low di versity late Arenig bryozoan assemblages of North America, Ireland, North C hina, Vajgach and Novaja Zemlja.