Extant cheilostomatous bryozoans of the Middle Miocene from the north Western Desert, Egypt

Abstract

Twenty-nine extant Bryozoan species, belonging to the order Cheilostomata are described. They are from the Middle Miocene Marmarica Formation of the northern Western Desert in Egypt. The described bryozoans are collected from Matruh and Siwa areas.Fourteen species belong to the suborder Anasca, and the other fifteen species belong to the suborder Ascophora. The identified bryozoan species exhibit many zoarial growth forms. The encrusting forms are membraniporiform and celleporiform, while the erect forms are adeoniforms, eschariforms, vinculariiforms, reteporiform, and cellariiforms.They extend in the geologic record from the Eocene to the Recent, distributed mainly in the Tethyan realm, and recorded also from North America.The extant species are mainly of Mediterranean affinity, some are of wider distribution in the Atlantic and Pacific oceans, and are rarely cosmopolitan.