The specimen upon which this genus is based was collected by the Field Columbian Museum paleontological expedition of 1900, from the Grand River valley of western Colorado. Credit for its discovery is due to Mr. HW Menke of this Museum. The specimen consists of the humerus, coracoid, femur and ilium, all from the right side; the sacrum, seven thoracic and two caudal vertebrae, together with a number of ribs and other bones. The parts were, with the exception of the ribs, preserved in their relative positions, and as the specimen was isolated there can be no question that all belonged to one individual.

The distal end of the humerus was exposed, broken and displaced as surface fragments. Associated with its proximal end was the fairly well-preserved coracoid. Some fifteen feet farther along the hillside the sacrum and pelvic bones appeared lying with spines downward. Two partially weathered caudals were closely connected with the posterior end of the sacrum.