Holotype:
Locality: Mygatt-Moore (M&M) Quarry, Mesa County, Western Colorado.
Horizon: Middle Brushy Basin Member, Morrison Formation.
Biostratigraphy: Zone 3.
Age: Comobluffian age, Kimmeridgian Stage, Uppermost Malm Epoch, Late Jurassic.
Material: Fragmentary skeletons, some of a very large individual.