Note on the taxonomy of the family Notobranchaeidae and description of Notobranchaea bleekerae n. sp., a species new to science (Gastropoda, Pteropoda)

During the Amsterdam Mid North Atlantic Plankton Expedition 1983 (AMNAPE, 1983) (see Van der Spoel, in prep.), a gymnosomatous pteropod species new to science was collected. The single specimen, obtained in waters of the North Atlantic Drift with a rectangular midwater trawl, belongs to the family Notobranchaeidae Pelseneer, 1886. According to Tesch (1950) the family consists of two genera, viz., Notobranchaea Pelseneer, 1886, and Prionoglossa Tesch, 1950. However, a close taxonomic study has revealed that a division into two genera is doubtful, as no grouping of characters could be found at all.