Genus: Leonardus BONAPARTE, 1990
Etymology: In honor of Guiseppe Leonardi, Italian-Brazillian vertebrate paleontologist.

Species: cuspidatus BONAPARTE, 1990
Etymology:

Holotype: MACN-RN 172

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: A fragment of a left maxilla with four of the last molars complete.

Hypodigm:

MACN-RN 231: A complete left upper molar.