After Cifelli & Diaz, 1989 and McKenna & Bell, 1997

<==o †Proterotheriidae Ameghino, 1887 [Proterotheroidea]
   |--o †Anisolambdinae
   |  |-- †Paranisolambda
   |  |-- †Richardolydekkeria [Lopholambda, Heterolambda]
   |  |-- †Anisolambda [Josepholeidya, Eulambda, Anissolambda]
   |  |-- †Wainka
   |  |-- †Xesmodon
   |  `-- †Protheosodon [Heteroglyphis]
   `--o †Proterotheriinae
      |?- †“Proterotherium” dodgei
      |-- †Deuterotherium
      |-- †Megadolodus
      |-- †Eoproterotherium
      |-- †Prolicaphrium
      |--o †Prothoatherium Ameghino, 1902 [Licaphrops; Paramacrauchenia; NeodolodusHoffstetter & Soria, 1986]
      |  |-- †P. colombianus (Hoffstetter & Soria, 1986) [Neodolodus colombianus Hoffstetter & Soria, 1986]
      |  `--+-- †P. lacerum
      |     `-- †P. scamnatum
      |-- †Licaphrium
      |--o †Diadiaphorus [Coelosoma]
      |  `-- †D. majusculus
      |--o †Thoatherium
      |  `-- †T. minisculum
      |-- †Brachytherium [Epitherium, Lophogonodon]
      |-- †Epecuenia
      |-- †Diplasiotherium
      `-- †Proterotherium

Reference(s):