Neornithes Gadow, 1893 - living birds Palaeognathae - palaeognaths see Cohort Palaeognathae Pycraft, 1900 ratites see Subcohort Ratitae Merrem, 1813 Family Rheidae Bonaparte, 1849 - rheas 1 Genus Rhea Brisson, 1760 [monotypic] 2 Genus Pterocnemia Gray, 1871 [monotypic]