After McKenna & Bell, 1997
<==o †Helohyidae |?- †Bunodentus |?- †Poeprodon |-- †Apriculus [Protelotherium] |-- †Ithygrammodon |-- †Lophiohys |-- †Parahyus |?-o †Achaenodon | |-- †A. insolens | `-- †A. robustus |-- †Pakkokuhyus `--o †Helohyus Marsh, 1872 |-- †H. lentus (Marsh, 1871) |-- †H. plicodon Marsh, 1872 |-- †H. valitus (Marsh, 1872) `-- †H. milleri Sinclair, 1914
Reference(s):
- Carroll, R. L., 1988: Vertebrate paleontology and evolution.
–W. H. Freeman and company, New York, 1988, 698. - Carroll, R. L., 1988: Appendix. 594-648.
in Carroll, R. L., 1988: Vertebrate paleontology and evolution.
–W. H. Freeman and company, New York, 1988, 698. - Gazin, C. L., 1976: Mammalian faunal zones of the Bridger Middle Eocene.
–Smithsonian Contributions to Paleobiology: No. 26, pp. iv-25 - McKenna, M. C. & Bell, S. K., (eds.) 1997: Classification of mammals – above the species level.
–Columbia University Press, New York, 1997, xii-631 - Métais, G., Qi, T., Guo, J. & Beard, K. C., 2005: A new bunoselenodont artiodactyl from the Middle Eocene of China and the early record of selenodont artiodactyls in Asia.
-Journal of Vertebrate Paleontology: Vol. 25, #4, pp. 994-997