Archaeogastropoda

The Altschnecken or Urschnecken ( Diotocardia or Archaeogastropoda ) were according to the system of Johannes Thiele ( 1925), an order of prosobranch ( Prosobranchia ). They were after Thiele evolutionarily a sideline of the other snails that still had a number of original features. So have the questions to this group yet double Family atria, double gills and excretory organs duplicate. They have very different shaped housing, which in many cases still have locations in nacre of the shell in contrast to all other snails. The groups were expected to Altschnecken, are mainly found in the sea, but also occur in fresh water or on land. Thiele expected to Archaeogastropoda the superfamilies Zeugobranchia (now invalid, contained the families Haliotidae, Pleurotomariidae, Bellerophontidae and Fissurellidae ) Patelloidea, Trochoidea, Neritoidea and Cocculinoidea.

The taxon Altschnecken has now been recognized as a polyphyletic taxon and abandoned.