Opisthokonta Cavalier-Smith 1987, nom. cl. inval. see Clade Opisthokonta Cavalier-Smith 1987 [Simpson & Medina 2020]
   Metazoa Haeckel 1874 - multicellular animals see Kingdom Animalia Linnaeus, 1758
     Epitheliozoa Ax, 1996
       Eumetazoa Bütschli, 1910 - eumetazoans
         Acrosomata Ax, 1996 see [unranked] Eumetazoa Bütschli, 1910
           Bilateria Hatschek, 1888 - bilaterians see Subkingdom Bilateria Hatschek, 1888
             Protostomia Grobben, 1908 see Infrakingdom Protostomia Grobben, 1908
               Lophotrochozoa Halanych, Bacheller, Aguinaldo, Liva, Hillis & Lake 1995 - lophotrochozoans
                 Spiralia Schleip, 1929 - spiralians see Superphylum Spiralia Schleip, 1929
                   Platyzoa Ax, 1987 see [unranked] Spiralia Schleip, 1929
                     1 Rotifera Cuvier, 1798 - rotifers see Phylum Syndermata Ahlrichs, 1995
                     2 Cycliophora Funch & Kristensen, 1995 - cycliophorans
                     3.1 Gnathostomulida Ax, 1956 - gnathostomulids
                     3.2 Platyhelminthes Gegenbaur, 1859 - flatworms