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
         (Achatinid Sigmurethra)
           Suborder Sigmurethra Pilsbry, 1900 see Group Sigmurethra Pilsbry, 1900
             Superfamily Streptaxoidea Gray, 1860 [monotypic]
               Family Streptaxidae Gray, 1860
                 Subfamily Enneinae Bourguignat, 1883
                   Genus Gulella Pfeiffer, 1856
                     Subgenus Aenigmigulella Pilsbry & Cockerell, 1933