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 †Pelagielliformes Runnegar & Pojeta, 1985
             Family †Pelagiellidae Knight, 1952
               1 Genus †Costipelagiella Horný, 1964
               2 Genus †Pelagiella Matthew, 1895
               3 Genus †Tannuspira Missarjevsky, 1989