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
Marsupialiformes Vullo, Gheerbrant, de Muizon & Néraudeau, 2009
[Order] †Alphadontia Archer, 1984
[Suborder] †Hatcheriformes Case, Goin & Woodburne, 2005
Genus †Xenostylus Goin, Case, Woodburne, Vizcaino & Reguero, 1999, nom. illeg.