Bryozoan internal moulds from the La Meseta Formation (Eocene) of Seymour Island, Antarctic Peninsula

Abstract

AbstractThe loose, small zooecia of the cheilostome bryozoans have been discovered in the lowermost part of the LaMeseta Formation on Seymour (Marambio) Island. They systemati− cally include the representatives of Beanidae Canu et Bassler, Catenicellidae Busk, Savi− gnyellidae Levinsen, and Calwelliidae MacGillivray. The bryozoan assemblage is comprised of separate, small−sized internal moulds dominated by distinct, boat−shaped zooecia belonging to Beania, scarce, unizooidal internodes tentatively included into a ditaxiporine catenicellid ?Vasignyella, and representative of the family Savignyellidae. A few branched segments composed of multiserial zooecia arranged back to back were tentatively incorporated into ?Malakosaria. Beania, marks the oldest fossil record, whereas representatives of Savignyelli− dae along with ditaxiporine catenicellid and ?Malakosaria are for the first time reported from Antarctica. The relationship between the taxonomic composition, colony growth−patterns rep− resented by membraniporiform/petraliform, catenicelliform and cellariform, along with asso− ciated biota and sedimentary structures of the LaMeseta Formation implies nearshore environ− ment, with considerable wave action, and warm climatic conditions.