Class Mammalia Linnaeus, 1758 - mammals
   Subclass Acrotheria Averianov & Lopatin, 2011
     Infraclass Zatheria McKenna, 1975 see Clade Zatheria McKenna 1975
       Superlegion Theria Parker & Haswell, 1897 see Subclass Theria Parker & Haswell, 1897
         1 Legion †"Tribotheria" Butler, 1978 [paraphyletic]
         2 Legion Metatheria Huxley, 1880 see Infraclass Metatheria Huxley, 1880
         3 Legion Eutheria Gill, 1872 see Infraclass Eutheria Gill, 1872