Species: intermedius COPE 1894 (nomen dubium)
Etymology:

Holotype: ANSP 10

Locality: Great Bend of the Missouri River, Big Bend of the Missouri River, South Dakota.

Horizon: Pierre Formation.

Biostratigraphy:

Age: Santonian Stage, Lower Senonian Subepoch, Early Gulf Epoch, Late Cretaceous.

Material: 19 cervical centra.
_____________________________________________________________________________________

Species: sternbergi WILLISTON 1906 (nomen dubium)
Etymology:

Holotype: KUVP 1312

Locality: Unknown, Gove County, Kansas.

Horizon: Niobrara Formation.

Biostratigraphy:

Age: Senonian Subepoch, Gulf Epoch, Late Cretaceous.

Material: 2 cervical and 1 dorsal vertebrae and additional fragments.