Species: lentus MARSH, 1890
Etymology:

Holotype: YPM 429

Locality: Piedmont Quarry, Black Hills, 1 1/2 miles East of Piedmont, Meade County, South Dakota.

Horizon: Member? Morrison Formation.

Biostratigraphy: Zone?

Age: Age? Stage? Malm Epoch, Late Jurassic.

Material: 4 cervical, 6 dorsals, and 19 caudal vertebrae, sacrum, 1 sternal plate, 1 scapula, ilium, pubis, ischium, fragments of femur, tibia and fibula.
Note: Gastroliths were found with the specimen.