Genus: Neoplagiaulax LEMOINE, 1880
Etymology: Greek, neo, "new" + Plagiaulax; New Plagiaulax.

Species: ? burgessi ARCHIBALD, 1982 (Not Type)
Etymology:

Holotype: UCMP 116896

Locality: UCMP V73087, Flat Creek 5, Garfield County, Montana.

Horizon: Hell Creek Formation.

Biostratigraphy:

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

Material: Left LP4.

Referred material:

4 LP4.