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 †Yohelcionelloidea nom. null. see Superfamily Yochelcionelloidea Runnegar & Jell, 1976
               Family †Trenellidae Parkhaev, 2001
                 01 Genus †Figurina Parkhaev, 2001
                 02 Genus †Horsegullia Parkhaev, 2004
                 03 Genus †Mackinnonia Runnegar, 1990, nom. illeg.
                 04 Genus †Obscurella Vassiljeva, 1990, nom. illeg.
                 05 Genus †Oelandia Westergård, 1936
                 06 Genus †Parailsanella Zhegallo, 1987
                 07 Genus †Perssuakiella Peel, 1988
                 08 Genus †Prosinuites Poulsen, 1967
                 09 Genus †Rugaeconus Vassiljeva, 1990
                 10 Genus †Trenella Parkhaev, 2001
                 11 Genus †Tubatoconus Feng, Sun & Qian, 2000
                 12 Genus †Xianfengella He & Yang, 1982