Mammalia Linnaeus 1758 [Rowe 1988], nom. cl. inval. see Class Mammalia Linnaeus, 1758
Status: extant
   1 †Mesonychia Matthew, 1937
  Status: fossil
   2.1 Perrissodactyla
  Status: extant
   2.2 Cetartiodactyla Montgelard, Catzeflis & Douzery 1997 see Order Cetartiodactyla Montgelard, Catzeflis & Douzery, 1997
  Status: extant