Species: delfsi MOOK, 1967
Etymology:

Holotype: Cleveland Museum of Natural History, No. 8028

Locality: Cleveland Museum Quarry, Red Canyon, north of Canon City, Fremont County, Colorado.

Horizon: Salt Wash Member equivalent, Morrison Formation.

Biostratigraphy: 'Haplocanthosaurus' biozone.

Age: Comobluffian age, Kimmeridgian Stage, uppermost Malm Epoch, Late Jurassic.

Material: Skull missing the anterior tip, jaw, most of the precaudal and a few caudal vertebrae, a few limb bones and scutes.

Referred material:

SMITH, ALLEN, SANDER & STADTMAN, 2010

Locality: Dry Mesa Quarry 1, sec. 23, T.50N, R.14, Mesa County, on the Uncompahgre Plateau, in Western Colorado.

Horizon: Lower Upper Brushy Basin Member, Morrison Formation.

Biostratigraphy: Zone 2.

Age: Lower Part, Comobluffian age, Kimmeridgian Stage, Uppermost Malm Epoch, Late Jurassic.

Material:

BYU 17628: Complete skull and mandibles.