Genus: Oxyprimus VAN VALEN, 1978
Etymology: Greek, oxys, “sharp” and Latin, primus, “first”: First oxyclaenid.

Species: erickseni VAN VALEN, 1978
Etymology:

Holotype: UMVP 1561

Locality: Harbicht hill, Montana.

Horizon: Hell Creek Formation.

Biostratigraphy:

Age: Lancian age, upper Maastrichtian Stage, uppermost Senonian subepoch, Upper Gulf Epoch, Late Cretaceous.

Material: Right LM1.

Referred material:

cf. O. erickseni JOHNSTON & FOX, 1984

Locality: MHBT Quarry, near the village of Ravenscrag, Saskatchewan, Canada.

Horizon: Lower Ravenscrag Formation.

Biostratigraphy:

Age: Lancian age, uppermost Maastrichtian Stage, uppermost Senonian subepoch, Upper Gulf Epoch, Late Cretaceous.

Material:

UA 16051: Fragmentary dentary having m2-3.