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 Archaeogastropoda Thiele, 1925 see Order Vetigastropoda Salvini-Plawen, 1980
                 Superfamily Fissurellacea Fleming, 1822 see Superfamily Fissurelloidea Fleming, 1822
                   Family Fissurellidae Fleming, 1822 - keyhole limpets
                     Subfamily Emarginulinae Children, 1834
                       Genus Emarginula Lamarck, 1801
                       Genus Clypidina Gray, 1847
                       Genus Emarginella Pilsbry, 1891
                       Genus Hemitoma Swainson, 1840
                       Genus Notomella Cotton, 1957
                       Genus Puncturella Lowe, 1827
                       Genus Rimula Defrance, 1827
                       Genus Scutus Montfort, 1810
                       Genus Tugalia Gray, 1857, nom. illeg. see Genus Tugali Gray, 1843
                       Genus Zeidora Adams, 1860