Phylum Mollusca Linnaeus, 1758 - molluscs
   Class Gastropoda Cuvier, 1795 - snails and slugs
     Subclass Divasibranchia Minichev & Starobogatov, 1975
       Order Stylommatophora Schmidt, 1855 see Infraorder Stylommatophora Schmidt, 1855
         (Helicid Sigmurethra)
           Superfamily Helixarionoidea Bourguignat, 1883, orth. inval.
             Family Urocyclidae Simroth, 1889
               Subfamily Urocyclinae Simroth, 1889
                 Genus Trichotoxon Simroth, 1888
                   Subgenus Spirotoxon Simroth, 1897