Species: polyonychius McINTOSH, COOMBS & RUSSELL, 1992
Etymology: Greek, polys, "many" and Greek, onyx, "claw" in reference to the claws of digits IV and probably V.
Holotype: Amherst Collage, AC 663
Locality: Vicinity of Lance Creek, eastern Wyoming.
Horizon: Uncertain, probably Morrison Formation.
Age: Late Jurassic.
Material: Distal ends of left(?) ulna and radius, partial head of left femur, proximal end of left tibia, distal end of right tibia, left astragalus, left metatarsal I, II, III and proximal half of metatarsal IV, left phalanges I-1, III-1, and IV-1, unguals of I, II, III (proximal half) and IV, possible ungual of V.