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 Opisthobranchia Milne-Edwards, 1848 - opisthobranchs see Order Opisthobranchia Milne-Edwards, 1848
               Order Nudibranchia Cuvier, 1814 - "true" nudibranchs
                 Suborder Doridoidea Rafinesque, 1815 see Suborder Doridina Odhner, 1934
                   Superfamily Eudoridacea Boss, 1982, nom. inval., orth. inval. see Superfamily Eudoridoidea Vaught, 1989, nom. inval.
                     Family Hexabranchidae Bergh, 1891
                       Genus Hexabranchus Ehrenberg, 1828
                         Hexabranchus sanguineus (Rüpp. & Leuck.)