The Articles illustrations are from Sefve 1910, Sefve 1912, and Boule et Thévenin 1920.
According to Alberdi (1993) the synonyms for
Hippidion principale are (among others): Onohippidion compressidens and Hippidium bonaerense;
Hippidion devillei: Hippidium bolivianum, Onohippidion peruanum, (...)