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 Gnathostomulida Ax, 1956 - gnathostomulids
           Order Filospermoidea Sterrer, 1972
             Family Haplognathiidae Sterrer, 1972
               Genus Haplognathia Sterrer, 1970
                 Haplognathia simplex (Sterrer, 1966)