Genus: Trapalcotherium ROUGIER, CHORNOGUBSKY, CASADIO, ARANGO & GIALLOMBARDO, 2008
Etymology: In reference to Bajo Trapalco, Rio Negro Province, Patagonia, Argentina, the basin where the Cerro Tortuga locality is located, and Greek, therium, "beast," commonly used in taxonomy as a suffix meaing mammal.

Species: matuastensis ROUGIER, CHORNOGUBSKY, CASADIO, ARANGO & GIALLOMBARDO, 2008
Etymology: In reference to Puesto El Matuasto, a herder's shed facilitated by the Cabaza family for the use of the expedition while prospecting at the Cerro Tortuga locality.

Holotype: MML-Pb 16

Locality: Microvertebrate layer, Cerro Tortuga, Rio Negro Province, Patagonia, Argentina.

Horizon: 38 meters below the top of the Allen Formation.

Biostratigraphy:

Age: Maastrichtian Stage, Uppermost Senonian Subepoch, Uppermost Gulf Epoch, Late Cretaceous.

Material: Left m1.