Systema naturæ - nature
   Universum - universe see [unranked] Mundus Plinius
     naturalia - natural bodies
       Regnum Animale nom. inval. - animal kingdom see Kingdom Animalia Linnaeus, 1758
         Class Aves Plinius, nom. inval. - birds see Class Aves Linnaeus, 1758
           Order Anseres nom. inval. see Order Anseres Linnaeus, 1758
             Genus Mergus nom. inval. see Genus Mergus Linnaeus, 1758
               1 Mergus nom. inval.
               2 Merganser nom. inval.