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 Picae Linnaeus, 1758 see Parvclass Picae (C. Linnaeus, 1758)
             Genus Picus Linnaeus, 1758
               Picus erythrocephalus Linnaeus, 1758 see Melanerpes erythrocephalus (C. Linnaeus, 1758)