Class Mammalia Linnaeus, 1758 - mammals
Count: [*†*] 5o; †16o;76f;282g;438s
   Subclass Boreosphenida Luo, Cifelli & Kielan-Jaworowska, 2001 - tribotherians see Clade Boreosphenida Luo, Cifelli & Kielan-Jaworowska 2001
  Count: [*†*] 4o; †5o;24f;82g;141s
     Infraclass Metatheria Huxley, 1880
    Count: 2o; †1o;7f;26g;62s
       Cohort Marsupialia Jameson, 1818 - marsupials
      Count: 2o; †1o;6f;19g;54s
         Superorder "Ameridelphia" Szalay, 1982 [paraphyletic] see Clade Ameridelphia Szalay 1982
        Count: 2o; †1o;6f;19g;54s
           Order "Didelphimorphia" Gill, 1872 [paraphyletic]
          Count: [†*] †4f;13g;46s
             Family †Alphadontidae Marshall, Case & Woodburne, 1990 [paraphyletic]
            Count: [†*] †6g;25s [24 Apr 2022]
               1 Genus †Alphadonᵀ Simpson, 1927
              Count: [†*] †10s [24 Apr 2022]
               2 Genus †Aenigmadelphys Cifelli & Johanson, 1994 [monotypic]
              Count: [†*] †1s [24 Apr 2022]
               3 Genus †Albertatherium Fox, 1971
              Count: [†*] †2s [24 Apr 2022]
               4 Genus †Protalphadon Cifelli, 1990
              Count: [†*] †2s [24 Apr 2022]
               5 Genus †Turgidodon Cifelli, 1990
              Count: [†*] †7s [24 Apr 2022]
               6 Genus †Varalphadon Johanson, 1996
              Count: [†*] †3s [24 Apr 2022]