organisms see Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
   Kingdom Animalia Linnaeus, 1758 - animals
     Eumetazoa Bütschli, 1910 - eumetazoans
       Bilateria Hatschek, 1888 - bilaterians see Subkingdom Bilateria Hatschek, 1888
         Protostomia Grobben, 1908 see Infrakingdom Protostomia Grobben, 1908
           Aschelminthes Grobben, 1910 see [unranked] Protostomia Grobben, 1908
             Phylum Chaetognatha Leuckart, 1854 - chaetognaths
               Genus Spadella Langerhans, 1880
                 Spadella cephaloptera (Busch, 1851)