Species: major BONAPARTE, 1990
Etymology: Latin, major, "greater."
Holotype: MACN-RN 171
Locality: West slope of Cerro Cuadrado, Arroyo Verde, Rio Negro Province, Patagonia, Argentina.
Horizon: Top of the Cerrito del Mamifero, middle section of the Los Alamitos Formation.
Biostratigraphy:
Age: Allenian Tetrapoda Assemblage, Late Campanian-Early Maastrichtian Stage, Senonian Subepoch, Gulf Epoch, Late Cretaceous.
Material: Complete crown of a right upper molar.
Note: Quirognatheridae