The genus was first described by Ameghino 1895. He distinguished it from the Santacrucian (late Early Miocene) Astrapotherium (Burmeister 1879) based on the greater number of upper and lower molars. Although later researchers disagreed and concluded that Ameghino based his conclusion on very fragmentary materials, they mostly agreed to distinguish the genus from other groups of astrapotherians.[1]
Ameghino, Florentino (1894). "Sur les oiseaux fossiles de Patagonie; et la faune mammalogique des couches à Pyrotherium". Boletin del Instituto Geográfico Argentino. 15: 501–660. OCLC85042509.
Ameghino, Florentino (1895). Première contribution à la connaissance de la faune mammalogique des couches à Pyrotherium. Buenos Aires: P.E. Coni. OCLC40071157.
Burmeister, Hermann (1879). Description physique de la République Argentine : d'après des observations personnelles et étrangères. Vol. 3 Animaux vertébrés, 1. partie, Mammifères vivants et éteints. Paris: Savy. p. 520. OCLC162707154.