Species: arizonensis HUNT, LUCAS, HECKERT, SULLIVAN & LOCKLEY, 1998
Etymology: Alludes to the state of Arizona, which yielded the holotype.
Holotype: UCMP 34498
Locality: Placerias quarry (UCMP A269, MNA 207C), Big Hollow Wash near Romero Springs, a small valley 6 1/2 miles (approximately 10.4 km) S 65"W of St. Johns, Apache County, Arizona. (Located 0.3 miles northwest of Romero Springs at approximately Long. 109'28'W and lat. 34’27”N on the USGS St. Johns quadrangle of 1921.)
Horizon: Bluewater Creek Formation, Lower Chinle Group.
Biostratigraphy:
Age: Adamanian, Latest Carnian Stage, Late Triassic Epoch, Late Triassic.
Material: Incomplete sacrum, distal ends of fused tibia-fibulae-astragalae, left and right tibia, fibula, astragalus and calcanum (Strongly fused).
Note: LONG & MURRY, 1995 list the following as Theropoda incertae sedis.
Paratypes:
UCMP (192A-E): Proximal right femur.
UCMP (A269/CG2): Sacrum with 4 fused vertebrae.
UCMP (A269/CK2-1): Proximal extremity of left pubis.
UCMP (A269/CF2-7): Incomplete sacrum with 2 fused centra.
UCMP (A269/C63M): Sacrum with 3 fused centra.
Referred material:
LONG & MURRY, 1995, fig 192K-L: A proximal left pubis.