[clarification needed] The most derived of the astrapotherians, they were also the largest and most specialized mammals in the Tertiary of South America.

Around 1900, Argentine paleontologist Florentino Ameghino described eight Colhuehuapian (Early Miocene) species from specimens he found south of Lake Colhué Huapi in Patagonia and grouped them into three genera: Parastrapotherium, Astrapotherium, and Astrapothericulus.

It was obvious to Ameghino that these species represented a great diversity, ranging in size from a peccary to a rhinoceros, but his description was based entirely on fragmentary and not always comparable dental remains.

[1] According to Kramarz & Bond 2009, Astrapotheriidae includes two clades, Astrapotheriinae and Uruguaytheriinae, and a number of early genera (Astrapotheriidae incertae sedis): Astraponotus (Middle Eocene), Maddenia (Early Oligocene), and Parastrapotherium (Late Oligocene-Early Miocene).

Most genera have been found in Patagonia and adjacent areas in Argentina and Chile; whereas members of Uruguaytheriinae have been found further north: Xenastrapotherium (Late Oligocene-Middle Miocene of northern South America), Granastrapotherium (Middle Miocene of Colombia), Uruguaytherium (uncertain age, from Uruguay).