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.

Referred material:

FMNH UC 685: Skull, dorsal armor and miscellaneous limb bones.

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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.

Referred material:

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.

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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.

Referred material:

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.

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Species: olsoni DEMAR, 1967
Etymology:

Holotype: UT 31189-8

Locality: Thaxton Ranch Locality, Clay County, Texas.

Horizon: Nocona Formatin, Wichita Group.

Biostratigraphy:

Age: Early Permian.

Material: Two-thirds of a skull, including the almost complete anterior portion, and part of the posterior portion on one side.

Referred material:

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.

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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.

Biostratigraphy:

Age: Early Permian.

Material: Skull and anterior portion of postcranial skeleton.