Mammalia Linnaeus 1758 [Rowe 2020]
   Theria Parker & Haswell 1897 [McKenna 1975] see Subclass Theria Parker & Haswell, 1897
     Metatheria Huxley 1880 [O'Leary, Allard, Novacek, Meng & Gatesy 2004] see Infraclass Metatheria Huxley, 1880
       Marsupialiformes Vullo, Gheerbrant, de Muizon & Néraudeau, 2009
         †Ameridelphia Szalay 1982
           Sudameridelphia Szalay 1994
             Notometatheria Kirsch, Lapointe & Springer 1997
               1.1 †Sternbergiidae Szalay, 1994
               1.2.1 Genus †Herpetotherium Cope, 1873
               1.2.2 [Family] †Derorhynchidae Marshall, 1987
               2 Marsupialia Jameson 1818 [O'Leary, Allard, Novacek, Meng & Gatesy 2004] see Cohort Marsupialia Jameson, 1818