Class Mammalia Linnaeus, 1758 - mammals †"Symmetrodontans" Simpson, 1925, incertae sedis see Infraclass Symmetrodonta Simpson, 1925 Superlegion Trechnotheria McKenna, 1975 see Clade Trechnotheria McKenna 1975 Family †Spalacotheriidae Marsh, 1887 Genus †Spalacotheriumᵀ Owen, 1854, incertae sedis †Spalacotherium tricuspidensᵀ Owen, 1854