<==o ALTUNGULATA [Paenungulata]
   |?- †Meniscotheriidae
   |-- †Phenacodontidae
   `--+-- †Radinskya yupingae [is an embrithopod??]
      `--+?- †Loxolophidae [Arctocyonidae: Loxolophinae]
         |-- †Phenacolophidae
         `--o PANTOMESAXONIA
            |-- ?TETHYTHERIA [URANOTHERIA]  (norsunsukuiset ungulaatit)
            `-- PERISSODACTYLA (kavioeläimet)

Reference(s):

McKenna, M. C. & Bell, S. K., (eds.) 1997: Classification of mammals – above the species level.

–Columbia University Press, New York, 1997, xii-631
Nowak, R. M., 1991: Walker's Mammals of the World; Part 1.

–The Johns Hopkins University Press, Baltimore and London, 1991, xlviii-642-lxiii

Nowak, R. M., 1991: Walker's mammals of the World; Part 2.

–The Johns Hopkins University Press, Baltimore and London, 1991, xii-643-1629

   Froelich, D. J., 1999: Phylogenetic systematics of basal perissodactyls.
–Journal of Vertebrate Paleontology: Vol. 19, #1, pp. 140 - 159