Holotype:

Locality: Howe Ranch, Howe Quarry located at the very foot of the big Horn Mountains, near the original Cloverly Post Office, 25 miles northeast of Greybull, and 25 miles south of the Montana line, Big Horn County, Wyoming.

Horizon: Salt Wash Member, Morrison Formation.

Biostratigraphy: Zone 2.

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

Material: Fragmentary skeletons with skin impressions and trangular spines and gastroliths.