After McKenna & Bell, 1997, and Foss, 2007

<==o †Helohyidae Marsh, 1877
   |?- †Bunodentus [not recognized by Foss (2007)]
   |?- †Poeprodon [not recognized by Foss (2007)]
   |?- †Apriculus [Protelotherium] [not recognized by Foss (2007)]
   |?- †Ithygrammodon [not recognized by Foss (2007)]
   |?- †Lophiohys [not recognized by Foss (2007)]
   |?- †Pakkokuhyus [not recognized by Foss (2007)]
   |-- †Parahyus vagus Marsh, 1876
   |-- †Simojovelhyus pocitosense Ferrusquía-Villafranca, 2006
   |-- †Dyscritochoerus lapointensis Gazin, 1956 [has been treated as an entelodontid]
   |--o †Achaenodon Cope, 1873
   |  |-- †A. insolens Cope, 1873
   |  |-- †A. robustus Osborn, 1883
   |  |-- †A. uintense Osborn, 1895
   |  `-- †A. fremdi Lucas et al., 2004
   `--o †Helohyus Marsh, 1872
      |-- †H. lentus (Marsh, 1871)
      |-- †H. plicodon Marsh, 1872
      |?- †H. sp. [Stucky, 1998]
      |?- †H. valitus (Marsh, 1872) [not recognized by Foss (2007)]
      `?- †H. milleri Sinclair, 1914 [not recognized by Foss (2007)]

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