Neornithes Gadow, 1893 - living birds
   Neognathae Pycraft 1900 see Cohort Neognathae Pycraft, 1900
     Galloanserae Sibley, Ahlquist & Monroe Jr., 1988 see Subcohort Galloanserae Sibley, Ahlquist & Monroe Jr., 1988
       [Order] Anseriformes Wagler, 1831 - waterfowl and screamers
         Family Anatidae Vigors, 1825 - ducks, geese, swans
           Subfamily Tadorninae Reichenbach - sheldrakes
             Genus Tachyeres Owen, 1875
               1 Tachyeres patachonicus (King, 1831) - flying steamer duck
               2 Tachyeres pteneres (Forster, 1844) - Magellanic steamer duck
               3 Tachyeres brachypterus (Latham, 1790) - Falkland Island steamer duck
               4 Tachyeres leucocephalus Humphrey & Thompson, 1981 - white-headed steamer duck