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 Anas clypeata Linnaeus, 1758 - northern shoveler