Species: estesi GAFFNEY & HIATT, 1971
Etymology: In honor of Richard Estes.
Holotype: AMNH 2601
Locality: SW 1/4, NW 1/4, sec.1, T15N, R55E, near Glendive, Dawson County, Montana.
Horizon: Hell Creek Formation.
Biostratigraphy:
Age: Lancian age, upper Maastrichtian Stage, uppermost Senonian subepoch, Upper Gulf Epoch, Late Cretaceous.
Material: Skull.