Species: cretacea WHETSTONE, 1979
Etymology:

Holotype: KUVP 23488

Locality: SW 1/4 NW 1/4, S. 35, T 21N, R 37E, Garfield County, Montana.

Horizon: Hell Creek Formation.

Biostratigraphy:

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

Material: Skull lacking lower jaw, right stapes posterior horn of hyoid, right forelimb and girdle lacking phalanges of digits IV and V, left forelimb and girdle lacking pisiform and distal half of metacrarpal V, left hind limb and girdle lacking most of digits I and V, and the distal phalanx of digit If, right ilium, cervicals 3-7, anterior half of cervical 8, caudals 1-3 carapace and plastron.

Referred material:

BYRANT 1990

Locality: Eastern Montana.

Horizon: Hell Creek Formation.

Biostratigraphy:

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

Material:

UCMP 129730: Hypo-xiphilplastron.

HOLRYOD & HUTCHISON, 2002

Locality: V 86075, western North Dakota.

Horizon: Hell Creek Formation.

Biostratigraphy:

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

Material:

172420:

Locality: V 86095, western North Dakota.

Horizon: Hell Creek Formation.

Biostratigraphy:

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

Material:

172465: