living organisms see Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
   Superkingdom Eukaryotae see Domain Eukaryota Chatton, 1925
     Kingdom Animalia Linnaeus, 1758 - animals
       Subkingdom Eumetazoa Butschli, 1910 see [unranked] Eumetazoa Bütschli, 1910
         Phylum Mollusca Linnaeus, 1758 - molluscs
           Class Gastropoda Cuvier, 1795 - snails and slugs
             Subclass Prosobranchia Milne-Edwards, 1848 - prosobranchs see Class Gastropoda Cuvier, 1795
               Order Mesogastropoda Thiele, 1925 - mesogastropods see [unranked] mesogastropods
                 Superfamily Tonnacea Suter, 1913 see Superfamily Tonnoidea Suter, 1913 (1825)
                   1 Family Cassidae P.A. Latreille, 1825 - helmet snails see Subfamily Cassinae Latreille, 1825
                   2 Family Tonnidae Suter, 1913 (1825) - tuns
                   3 Family Ficidae Meek, 1864 (1840) - fig snails
                   4 Family Cymatiidae Iredale, 1913 see Family Ranellidae Gray, 1854
                   5 Family Bursidae Thiele, 1925 - frog snails