Mammalia Linnaeus 1758 [Rowe 1988], nom. cl. inval. see Class Mammalia Linnaeus, 1758
   Cetartiodactyla Montgelard, Catzeflis & Douzery 1997 see Order Cetartiodactyla Montgelard, Catzeflis & Douzery, 1997
     Whippomorpha Waddell, Okada & Hasegawa 1999 see Suborder Whippomorpha
       Cetacea Brisson 1762 see Suborder Cetacea Brisson, 1762
         Family †Protocetidae Stromer, 1908 [paraphyletic?]
           Genus †Natchitochia Uhen, 1998