<==o PERISSODACTYLA Owen, 1848 sensu McKenna and Bell, 1997 [Mesaxonia, Perissodactylomorpha] (kavioeläimet) |-- HIPPOMORPHA (hevosmaiset kavioeläimet) `--o CERATOMORPHA Wood, 1937 [Meropomorpha] (sarvikuonomaiset kavioeläimet) |--o †SELENIDA | |-- †BRONTOTHEROIDEA | `-- †CHALICOTHEROIDEA `--o TAPIROMORPHA (tapiirimaiset kavioeläimet) |-- RHINOCEROTOIDEA (sarvikuononsukuiset kavioeläimet) `--+-- †Heptodon calciculus `--o TAPIROIDEA (tapiirinsukuiset kavioeläimet) |-- †Isectolophidae `--+-- †Helaletidae [paraphyletic?] |-- †Lophiodontidae |-- †Deperetellidae [incl. Rhodopagidae] |-- †Lophialetidae [incl. Eoletidae] `-- Tapiridae Burnett, 1830 (tapiirit)Reference(s):
Froelich, D. J., 1999: Phylogenetic systematics of basal perissodactyls. –Journal of Vertebrate Paleontology: Vol. 19, #1, pp. 140 - 159 Holbrook, L. T., 2001: Comparative osteology of early Tertiary tapiromorphs (Mammalia; Perissodactyla) –Zoological Journal of the Linnean Society: Vol. 132, #1, pp. 1-54McKenna, M. C. & Bell, S. K., eds., 1997: Classification of mammals; above the species level.
Prothero, D. R. & Schoch, R. M. 1989: Classification of the Perissodactyla. 530-537. In Prothero, D. R. & Schoch, R. M. 1989: The evolution of perissodactyls. --Oxford University Press., New York. 1989.
--Columbia University Press, New York, 1997.