Imperium naturæ C. Linnaeus, 1758 - nature
   Mundus Plinius - physical world
     naturalia - natural bodies
       Regnum Animale C. Linnaeus, 1758 - animal kingdom see Kingdom Animalia Linnaeus, 1758
         Class Aves Linnaeus, 1758 - birds see Subclass Aves Linnaeus, 1758
           Order Anseres Linnaeus, 1758 see Suborder Anseres Linnaeus, 1758
             Genus Anas Linnaeus, 1758 - Pacific black duck
               01 Anas cygnus Linnaeus, 1758 see Cygnus cygnus (Linnaeus, 1758)
               02 Anas cygnoid Linnaeus, 1758 see Anser cygnoides (Linnaeus, 1758)
               03 Anas tadorna Linnaeus, 1758 see Tadorna tadorna (Linnaeus, 1758)
               04 Anas spectabilis Linnaeus, 1758 see Somateria spectabilis (Linnaeus, 1758)
               05 Anas fusca Linnaeus, 1758 see Melanitta fusca (Linnaeus, 1758)
               06 Anas nigra Linnaeus, 1758 see Melanitta nigra (Linnaeus, 1758)
               07 Anas anser Linnaeus, 1758 see Anser anser (Linnaeus, 1758)
               08 Anas erythropus Linnaeus, 1758 see Anser erythropus (Linnaeus, 1758)
               09 Anas canadensis Linnaeus, 1758 see Branta canadensis (Linnaeus, 1758)
               10 Anas caerulescens Linnaeus, 1758 see Anser caerulescens (Linnaeus, 1758)
               11 Anas bernicla Linnaeus, 1758 see Branta bernicla (Linnaeus, 1758)
               12 Anas mollissima Linnaeus, 1758 see Somateria mollissima (Linnaeus, 1758)
               13 Anas moschata Linnaeus, 1758 see Cairina moschata (Linnaeus, 1758)
               14 Anas bahamensis Linnaeus, 1758 - white-cheeked pintail
               15 Anas albeola Linnaeus, 1758 see Bucephala albeola (Linnaeus, 1758)
               16 Anas clypeata Linnaeus, 1758 - northern shoveler
               17 Anas platyrhynchos Linnaeus, 1758 - mallard
               18 Anas strepera Linnaeus, 1758 - gadwall
               19 Anas bucephala Linnaeus, 1758
               20 Anas clangula Linnaeus, 1758 see Bucephala clangula (Linnaeus, 1758)
               21 Anas rustica Linnaeus, 1758
               22 Anas perspicillata Linnaeus, 1758 see Melanitta perspicillata (Linnaeus, 1758)
               23 Anas glaucion Linnaeus, 1758
               24 Anas penelope Linnaeus, 1758 - Eurasian wigeon
               25 Anas acuta Linnaeus, 1758 - northern pintail
               26 Anas hyemalis Linnaeus, 1758 see Clangula hyemalis (Linnaeus, 1758)
               27 Anas ferina Linnaeus, 1758 see Aythya ferina (Linnaeus, 1758)
               28 Anas querquedula Linnaeus, 1758 - garganey
               29 Anas crecca Linnaeus, 1758 - common teal
               30 Anas histrionica Linnaeus, 1758 see Histrionicus histrionicus (Linnaeus, 1758)
               31 Anas minuta Linnaeus, 1758
               32 Anas circia Linnaeus, 1758
               33 Anas autumnalis Linnaeus, 1758 see Dendrocygna autumnalis (Linnaeus, 1758)
               34 Anas boschas Linnaeus, 1758
               35 Anas adunca Linnaeus, 1758
               36 Anas galericulata Linnaeus, 1758 see Aix galericulata (Linnaeus, 1758)
               37 Anas sponsa Linnaeus, 1758 see Aix sponsa (Linnaeus, 1758)
               38 Anas arborea Linnaeus, 1758 see Dendrocygna arborea (Linnaeus, 1758)
               39 Anas fuligula Linnaeus, 1758 see Aythya fuligula (Linnaeus, 1758)