organisms see Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
   Kingdom Animalia Linnaeus, 1758 - animals
     Subkingdom Eumetazoa Butschli, 1910 see [unranked] Eumetazoa Bütschli, 1910
       Bilateria Hatschek, 1888 see Subkingdom Bilateria Hatschek, 1888
         Acoelomata see [unranked] Acoelomates Hyman, 1951
           Phylum Gnathostomulida Ax, 1956 - gnathostomulids
             Genus Problognathia W. Sterrer & R.A. Farris, 1975
               Problognathia minima Sterrer & Farris, 1975