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 Acanthocephala Kohlreuther, 1771 - acanthocephalans see [unranked] Acanthocephala Kohlreuther, 1771
           Class Palaeacanthocephala (Meyer, 1931)
             Order Echinorhynchida Southwell & Macfie, 1925
               Family Fessisentidae Van Cleave, 1931
                 Genus Fessisentis Van Cleave, 1931
                   Fessisentis necturorum Nickol, 1967