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 Chordata Bateson, 1885 - chordates
           Subphylum Vertebrata Cuvier, 1812 - vertebrates
             Class Aves Linnaeus, 1758 - birds see Subclass Aves Linnaeus, 1758
               Subclass Neornithes Gadow, 1893 see Clade Neornithes Gadow, 1893
                 Superorder Palaeognathae Pycraft, 1900 see Cohort Palaeognathae Pycraft, 1900
                   Order Rheiformes Forbes, 1884 see Suborder Rheae Forbes, 1884
                     Family Rheidae Bonaparte, 1849 - rheas
                       Genus Pterocnemia Gray, 1871
                         Pterocnemia pennata (d'Orbigny, 1834) - lesser rhea