Zur Anatomie und systematischen Stellung der Architectonicidae (Mollusca, Allogastropoda)

The anatomy of the Architectonicidae is described. The family combines prosobranch and pentaganglionate (=euthyneuran) traits, but has evolved in a very specialized way as cnidaria-feeders. There is no close relationship to the Epitoniidae, and the taxon 'Heterogastropoda' is regarded as artificial. The closest relatives of the Architectonicidae are the Mathildidae and the Pyramidellidae, all united in a taxon Allogastropoda. This taxon is regarded as a connecting link between basal marine Caenogastropoda and the most primitive Pentaganglionata (e.g. Acteon, Ringicula ). The relationships of the Architectonicidae to the Rissoellidae and Omalogyridae are briefly discussed.