Vertebrata Cuvier, 1812 - vertebrates Gnathostomata Teleostomi Tetrapoda Hatschek & Cori 1896 [Gauthier, Kluge & Rowe 1988] Amniota Haeckel, 1866 [Gauthier, Kluge & Rowe 1988] - amniotes Class Mammalia Linnaeus, 1758 - mammals Subclass Theria Parker & Haswell, 1897 Theria of Metatherian-Eutherian grade Infraclass Eutheria Gill, 1872 Order †Litopterna Ameghino, 1889 Family †Macraucheniidae Gervais, 1855