Genus: Orretherium MARTINELLI, SOTO-ACUNA, GOIN, KALUZA, BOSTELMANN, FONSECA, REGUERO, LEPPE & VARGAS, 2021
Etymology: Aonikenk (original inhabitants of the patagonian plains in Chile and Argentina), orre, "teeth" and Greek, therium/therion, "beast."

Species: tzen MARTINELLI, SOTO-ACUNA, GOIN, KALUZA, BOSTELMANN, FONSECA, REGUERO, LEPPE & VARGAS, 2021
Etymology: Aonikenk, tzen, "five"; the number of teeth preesrved in the in locus sequence.

Holotype: CPAP-5007

Locality: From a small hill, named Mammal Quarry, located in teh Rio de Las Chinas Valley, 50°42'S, 72°32'W, Estancia Cerro Guido, Ultima Esperanza Province, Magallanes and Chilean Antartic Region, Chilean Patagonia, Chile.

Horizon: Lower levels of the Dorotea Formation.

Biostratigraphy:

Age: Late Campanian-Early Maastrichtian Stage, Senonian Subepoch, Gulf Epoch, Late Cretaceous.

Material: Patial left dentary with p2, p3 adn m1-m3.

Referred material:

CPAP-5008: Almost complete right upper P3 with some remains of the maxillary bone.