Phylum Mollusca Linnaeus, 1758 - molluscs
   Class Gastropoda Cuvier, 1795 - snails and slugs
     Subclass Prosobranchia Milne-Edwards, 1848 - prosobranchs see Class Gastropoda Cuvier, 1795
       Superorder Archaeogastropoda Thiele, 1925
         Order Vetigastropoda Salvini-Plawen, 1980 - archaeogastropods s.l.
           Superfamily Seguenzioidea Verrill, 1884 [monotypic]
             Family Seguenziidae Verrill, 1884
               01 Genus Seguenzia Jeffreys, 1876
               02 Genus Ancistrobasis Dall, 1889
               03 Genus Asthelys Quinn, 1987
               04 Genus Basilissa Watson, 1879
               05 Genus Basilissopsis Dautzenberg & Fischer, 1897
               06 Genus Calliobasis Marshall, 1983
               07 Genus Carenzia Quinn, 1983
               08 Genus Fluxinella Marshall, 1983
               09 Genus Guttula Schepman, 1908
               10 Genus Hadroconus Quinn, 1987
               11 Genus Rotellenzia Quinn, 1987
               12 Genus Seguenziella Marshall, 1983, nom. illeg. see Genus Quinnia Marshall, 1988
               13 Genus Seguenziopsis Marshall, 1983
               14 Genus Thelyssa Bayer, 1971
               15 Genus Thelyssina Marshall, 1983