Class Mammalia Linnaeus, 1758 - mammals
   Subclass Theria Parker & Haswell, 1897
     Infraclass Eutheria Gill, 1872
       Cohort Ferungulata
         Superorder Paenungulata Simpson, 1945 see Grandorder Paenungulata Simpson, 1945
           Order Sirenia Gill, 1872 - sea cows