Class Mammalia Linnaeus, 1758 - mammals
   Subclass Prototheria Gill, 1872 - monotremes
     Order Monotremata Bonaparte, 1837 - monotremes
       1 Family Tachyglossidae Gill, 1872 - spiny anteaters
       2 Family Ornithorhynchidae Gray, 1825 - platypuses