[Kingdom] Animalia Linnaeus, 1758 - animals
   Grade Enterozoa
     Grade Cœlomata
       Phylum Vertebrata (Lamarck, 1801)
         Branch Craniata Linnaeus, 1758
           Grade Gnathostoma
             Subgrade Pentadactyla lipobranchia
               Branch Amphicondyla [monotypic]
                 Class Mammalia Linnaeus, 1758 - mammals
                   Grade Cloacalia
                     Order Platypoda Gill, 1872 - platypuses see Order Monotremata Bonaparte, 1837
                       1 Genus Ornithorhynchus Blumenbach, 1800 - duck-billed platypus