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 Chordata Bateson, 1885 - chordates
           Subphylum Vertebrata Cuvier, 1812 - vertebrates
             Class Osteichthyes Huxley, 1880 - bony fishes see [unranked] Euteleostomi
               Subclass Actinopterygii Woodward, 1891 - ray-finned fishes see Class Actinopterygii Woodward, 1891
                 Order Anguilliformes Rafinesque, 1810 - eels
                   Suborder Anguilloidei Rafinesque, 1810
                     01 Family Anguillidae Rafinesque, 1815 - freshwater eels
                     02 Family Heterenchelyidae Regan, 1912
                     03 Family Moringuidae Gill, 1885 - spaghetti eels
                     04 Family Nemichthyidae Kaup, 1859 - snipe eels
                     05 Family Cyematidae Regan, 1912 - bobtail eels
                     06 Family Xenocongridae Regan, 1912 - false moray eels see Family Chlopsidae Rafinesque, 1815
                     07 Family Myrocongridae Gill, 1890
                     08 Family Muraenidae Rafinesque, 1815 - morays
                     09 Family Synaphobranchidae Johnson, 1862 - cutthroat eels
                     10 Family Simenchelyidae Gill, 1879 see Subfamily Simenchelyinae
                     11 Family Dysommatidae Gill, 1893 see Family Synaphobranchidae Johnson, 1862
                     12 Family Macrocephenchelyidae Fowler, 1934 see Family Congridae Kaup, 1856
                     13 Family Congridae Kaup, 1856 - conger eels
                     14 Family Muraenesocidae Kaup, 1859 - pike conger eels
                     15 Family Nettastomatidae Kaup, 1859 - duckbill eels
                     16 Family Serrivomeridae Trewavas, 1932 - sawtooth eels
                     17 Family Ophichthidae Günther, 1870 - snake eels and worm eels
                     18 Family Derichthyidae - longneck eels