Class Mammalia Linnaeus, 1758 - mammals
   Subclass Boreosphenida Luo, Cifelli & Kielan-Jaworowska, 2001 - tribotherians see Clade Boreosphenida Luo, Cifelli & Kielan-Jaworowska 2001
     Order †Aegialodontia Butler, 1978 [monotypic]
       ?Genus †Tribactonodon Sigogneau-Russell, Hooker & Ensom, 2001 [monotypic]
         †Tribactonodon bonfieldi Sigogneau-Russell, Hooker & Ensom, 2001