Species: texensis WILLISTON, 1914
Etymology: In reference to the state of Texas, where the specimen was found.
lectotype: FMNH UC684
Locality: Mitchell Creek, Archer County, Texas.
Horizon: Lower to middle Waggoner Ranch Formation (formerly Clyde Formation, upper Wichita Group) Upper Wichita Group.
Biostratigraphy: Land-vertebrate faunachron lower to middle C.
Age: Lower Leonardian Stage, Lower Rotliegendes Epoch, Early Permian.
Material: Skull, dorsal armor and miscellaneous limb bones.
FMNH UC 685: Skull, dorsal armor and miscellaneous limb bones.
Species: brevis CARROLL, 1964
Etymology: Latin, brevis, "short."
Holotype: MCZ 1424
Locality: Archer City bone bed, 1 mile southwest of Archer City, Archer County, Texas.
Horizon: Upper Archer City Formation (formerly Putnam Formation, Wichita Group), upper Bowie Group.
Biostratigraphy: Land-vertebrate faunachron upper A.
Age: Wolfcampanian stage, Lower Rotliegendes Epoch, Early Permian.
Material: Skull and lower jaw with 12 vertebrae, 9 armor plates, 9 ribs, left and right cleithra and scapulae, fragments of the clavicles and left humerus.
MCZ 3272: Partial skull and fragments of bone lower jaws, an almost complete pelvic girdle, and a part of sacral ribs, and the proximal portion of the left femur.
Species: arroyoensis DEMAR, 1967
Etymology: In reference of the Arroyo Formation, Texas.
Holotype: FMNH UR431
Locality: East Coffee Creek, Baylor County, Texas.
Horizon: Arroyo Formation, Lower Clear Fork Group.
Biostratigraphy: Land-vertebrate faunachron lower D.
Age: Middle Leonardian stage, upper Rotliegendes, Early Permian.
Material: Anterior two-thirds of a skull, including the entire skull roof to a point just posterior to the orbits, and the complete upper and lower jaws to the articulation on the right side.
FMNH UR808: A sacral rib and 5 articulated vertebrae.
FMNH UR809: Part of the anterior portion of the skull and sphenethmoid.
FMNH UR810: A nearly complete armor carapace.
FMNH UR811: The posterior part of the skull and braincase.
FMNH UR812: Part of the shoulder girdle and carapace.
Species: olsoni DEMAR, 1967
Holotype: UT 31189-8
Locality: Thaxton Ranch Locality, Clay County, Texas.
Horizon: Nocona Formatin, Wichita Group.
Age: Early Permian.
Material: Two-thirds of a skull, including the almost complete anterior portion, and part of the posterior portion on one side.
UT 3189-8: Consisting of a ventral posterior lateral part of a skull, including the maxillary, posterior part of the lower jaw, and the ventral part of the otic notch.
Species: reiszi HOLMES, BERMAN & ANDERSON, 2013
Etymology: Inhonor of Robert R. Reisz, whose contributions to vertebrate paleontology, in particular Permocarboniferous tetrapods faunas, are many and highly regarted.
Holotype: CM 41705
Locality: Arroyo del Agua, Rio Arriba County, New Mexico.
Horizon: El Cobre Canyon Formation.
Age: Early Permian.
Material: Skull and anterior portion of postcranial skeleton.