Öztürk, B. & van Aartsen, J. J. (2006). Indo-Pacific species in the Mediterranean. 5. Chrysallida micronana nom. nov. for Chrysallida nana (Hornung and Mermod, 1924) (Gastropoda: Pyramidellidae). Aquatic invasions. 1(4): 241-244.
More than 140 aquatic alien species (AAS) have been reported from coastlines of the North Sea and the Baltic Sea and from inland waters within the national borders of Germany. The majority of these species has established self-sustaining populations. The most important vectors of introduction are shipping, species imports for aquaculture purposes and species imports as part of the ornamental trade. Several AAS have reached German waters via shipping canals. Many species show a locally limited distribution, but almost half of all AAS have spread successfully across larger areas. Several introduced species are abundant and approximately 20 % of all AAS in Germany can be considered as invasive. Prime source regions are the north-western Atlantic, the Indo-Pacific, and the Ponto-Caspian region. For all source regions considered, the invasion rate has been increasing since the end of the last century.