This genus is poorly known due to the fragmentary nature of its fossils ; a comparison with some of its better-known relatives tends to indicate that it was roughly the size of a modern agouti.

The center of the lingual wall of the upper molars featured a small groove, less marked than in several of its relatives such as Prosotherium and Propachyrucos.

Hegetotheriopsis sulcatus was first described in 2013, based on fossil remains found in the Chubut Province of Argentine Patagonia, in terrains dated from the Early Miocene.

Other remains, found in the Cabeza Blanca locality of the Sarmiento Formation and attributed to the same species, are dated from the Late Oligocene.

Furthermore, fossils of this genus have also been found in the Agua de la Piedra,[1] Cerro Bandera, and Chichinales Formations of Mendoza, Neuquén, and Río Negro Provinces of Argentina.