Species: houssayi BONAPARTE & SORIA, 1985
Etymology:

Holotype: MACN-RN1

Locality: Rio Negro Province, Argentina.

Horizon: Los Alamitos Formation.

Biostratigraphy:

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

Material: Upper molar.

Referred material:

BONAPARTE

MACN-RN3: Molar.

MACN-RN4: Molar.

MACN-RN5: Molar.

MACN-RN7: Lower molar.

MACN-RN8: Lower molar.

MACN-RN9: Lower molar.

MACN-RN10: Lower molar.

MACN-RN11: Lower molar.

MACN-RN12: Lower molar.

MACN-RN141: Molar.

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Species: lamarquensis ROUGIER, CHORNOGUBSKY, CASADIO, ARANGO & GIALLOMBARDO, 2008
Etymology: Latinized version of Lamarque, the largest city in the area, and home of the Museo Municipal de Lamarque, which serves as repository of the specimens. The species name also recognizes the pioneering work being carred out by the personnel of this institution and thier invalauble help in making collection of the spceimens possible.

Holotype: MML-Pv 10

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: A right upper molar.

Referred material:

MML-Pv 11: A left upper molar.

MML-Pv 12: A lower molar fragment.