Mammalia Linnaeus 1758 [Rowe 1988], nom. cl. inval. see Class Mammalia Linnaeus, 1758
   Metatheria Huxley 1880 [O'Leary, Allard, Novacek, Meng & Gatesy 2004] see Infraclass Metatheria Huxley, 1880
     [Order] †Deltatheroida Kielan-Jaworowska, 1982
       1.1 Genus †Atokatheridium Kielan-Jaworowska & Cifelli, 2001
       1.2 Genus †Oklatheridium Davis, Cifelli & Kielan-Jaworowska, 2008
       2.1.1 Genus †Lotheridium Bi, Jin, Li & Du, 2015
       2.1.2.1 Genus †Deltatheridium Gregory & Simpson, 1926
       2.1.2.2 Genus †Deltatheroides Gregory & Simpson, 1926
       2.2.1 Genus †Sulestes Nessov, 1985
       2.2.2.1 Genus †Nanocuris Fox, Scott & Bryant, 2007
       2.2.2.2 Genus †Tsagandelta Rougier, Davis & Novacek, 2015