After Hooker, 1989
<==o Hippomorpha Wood, 1937 (horses and relatives; hevosmaiset kavioeläimet) |--o †Pachynolophoidea Pavlow, 1888 | `--o †Pachynolophidae Pavlow, 1888 | |?- †“Hyracotherium” sp.1 [=? †"Hyracotherium" seekensi] | `--+-- †Pachynolophus duvali Pomel, 1847 | `-- †Anchilophus depereti Gervais, 1852 `--o Equoidea Hay, 1902 (hevosensukuiset kavioeläimet) |?- †Hyracotherium craspedotum |?- †Hyracotherium index |?- †Indolophus Pilgrim, 1925 [Indolophidae Schoch, 1984] `--+-- †Cymbalophus cuniculus [“Hyracotherium” cuniculum] `--+-- †Systemodon tapirinum [“Hyracotherium” tapirinum] `--+-- †Pliolophus vulpiceps [“Hyracotherium” vulpiceps] |-- †Palaeotheriidae [Pachynolophoidea] `--+--o †Hyracotherium vasacciense (Cope, 1872) | `-- †H. v. venticolum `-- Equidae Gray, 1821 (horses; hevoset)
Reference(s):
- Albright III, L. B., 1998: New genus of tapir (Mammalia: Tapiridae) from the Arikareean (Earliest Miocene) of the Texas Coastal Plain.
–Journal of Vertebrate Paleontology: Vol. 18, #1, pp. 200-217 - Froehlich, D. J., 1999: Phylogenetic systematics of basal perissodactyls.
–Journal of Vertebrate Paleontology: Vol. 19, #1, pp. 140 - 159 - Froehlich, D. J., 2002: Quo vadis eohippus? – The systematics and taxonomy of the early Eocene equids (Perissodactyla).
–Zoological Journal of the Linnean Society: Vol. 134, #2, pp. 141-256 - Hooker, J. J., 1989: Character polarities in early perissodactyls and their
significance for Hyracotherium and infraordinal relationships. 79-101.
in Prothero, D. R. & Schoch, R. M., (eds.) 1989: The Evolution of Perissodactyls.
–Oxford University Press, New York, New York & Oxford, England, 1989, ix-537 - McKenna, M. C. & Bell, S. K., (eds.) 1997: Classification of mammals – above the species level.
–Columbia University Press, New York, 1997, xii-631 - Prothero, D. R. & Schoch, R. M. 1989: Classification of the Perissodactyla. 530-537.
in Prothero, D. R. & Schoch, R. M., (eds.) 1989: The evolution of perissodactyls.
–Oxford University Press., New York. 1989, ix-537 - Schoch, R. M., 1989: A brief historical review of Perissodactyl classification. 13-23.
in Prothero, D. R. & Schoch, R. M., (eds.) 1989: The Evolution of Perissodactyls.
–Oxford University Press, New York, 1989, ix-537 - Thewissen, J. G. M., Williams, E. M. & Hussain, S. T., 2001: Eocene mammals faunas from Northern Indo-Pakistan.
–Journal of Vertebrate Paleontology: Vol. 21, #2, pp. 347-366