Phylum Mollusca Linnaeus, 1758 - molluscs
   Conchifera Gegenbaur, 1878 see Subphylum Conchifera Gegenbauer, 1878
     Cyrtosoma
       Class Gastropoda Cuvier, 1795 - snails and slugs
         Subclass †Archaeobranchia Parkhaev, 2001
           Order †Helcionelliformes Golikov & Starobogatov, 1975
             Superfamily †Helcionelloidea Wenz, 1938 see Superfamily Scenelloidea Miller, 1889
               Family †Igarkiellidae Parkhaev, 2001, nom. illeg.
                 1 Genus †Gonamella Valkov & Karlova, 1984
                 2 Genus †Igarkiella Vassiljeva, 1998, nom. illeg.
                 3 Genus †Mastakhella Missarjevsky, 1989
                 4 Genus †Protoconus Yü, 1979