Species: arctatus COPE, 1874 (nomen dubium)
Etymology: Greek, arctatus, "compressed."
= Cinodon arctatus COPE, 1874 (nomen nudum)
= Trachodon arctatus (COPE, 1874) KUHN, 1936 (nomen dubium)
= Thespesius arctatus (COPE, 1874) STEEL, 1969 (nomen dubium)

Holotype: AMNH 3951

Locality: Lodge Pole Creek, Colorado.

Horizon: Denver Formation.

Biostratigraphy:

Age: Late Maastrichtian Stage, Upper Senonian Subepoch, Upper Gulf Epoch, Late Cretaceous.

Material: Portion of right maxilla (A), 2 dorsal vertebrae (C), distal end of metatarsal (D E), distal end of ulna (F).

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Species: stenopsis COPE, 1875 (nomen dubium)
Etymology:
= Trachodon stenopsis (COPE, 1875) KUHN, 1936 (nomen dubium)
= Thespesius stenopsis (COPE, 1875) STEEL, 1969 (nomen dubium)

Holotype: AMNH (uncatalogued)

Locality: Milk River, near Wild Horse Lake, almost on the International Boundary, Cypress County, Alberta Province, Canada.

Horizon: Judith River Formation.

Biostratigraphy:

Age: Judithian age, Campanian Stage, Senonian subepoch, Upper Gulf epoch, Late Cretaceous.

Material: Fragments of a right maxilla with teeth.