Species: gracilis WILLISTON, 1910
Etymology: Latin, gracilis, "slender."

Holotype: FMNH UR 341

Locality: Craddock bonebed, in a ravine near the west line of Craddock's ranch, near Seymour, 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: Skull and skeleton.

WILLISTON,

Referred material:

CNHM UC 659, 660, 662: 3 fragmentary skeletons lacking skull, neck and tail.

CNHM UC 661: 2 skulls and 2 cervical vertebrae.

CNHM UC 1708: Fragmentary skeleton.

 

Locality: Texas.

Horizon: Petrolia Formation (formerly Belle Plains Formation, middle Wichita Group), Lower Wichita Group.

Biostratigraphy: Land-vertebrate faunachron upper B.

Age: Upper Wolfcampanian stage, Upper Rotliegendes Epoch, Early Permian.

Material:

MCZ 4380: Skull, vertebrae 1-20 with some associated ribs, portions of the pectoral girdle, right forelimb with a partial carpus, left forelimb and a partial manus, partial right femur, tibia, fibula and a complete right pes.

After REISZ, BERMAN & SCOTT, 1984

Modified from REISZ, BERMAN & SCOTT, 1984

MCZ 8828: Vertebral series from presacral vertebrae 20 to caudal 17, caudal with some associated ribs, pelvic girdle, right hindlimb and pes except for the phalanges and proximal half of the left femur.

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Species: casei (BROOM, 1913) VAUGHN, 1955
Etymology: In honor of E. C. Case.
= Ophiodeirus casei BROOM, 1913

Holotype: AMNH 4685

Locality: Godlin's Creek (properly Godwin), Sec. 1, SPRR Co., A-298, Baylor County, Texas.

Horizon: Lowermost Petrolia Formation (formerly Upper Admiral Formation, middle Wichita Group), Lower Wichita Group.

Biostratigraphy: Land-vertebrate faunachron middle B.

Age: Upper Wolfcampanian stage, Upper Rotliegendes Epoch, Early Permian.

Material: Fragmentary skull and fragmentary skeleton.

Referred material:

AMNH 4686: Fragmentary skull and fragmentary skeleton.

 

VAUGHN 1955

Locality: 1 1/2 miles west of Williams Ranch, Turbeville Pasture, Bar X Ranch, Baylor County, Texas.

Horizon: Petrolia Formation (formerly Belle Plains Formation, middle Wichita Group), Lower Wichita Group.

Biostratigraphy: Land-vertebrate faunachron upper B.

Age: Upper Wolfcampanian stage, Upper Rotliegendes Epoch, Early Permian.

Material:

MCZ 1259: Mandibular scrap, a few incomplete vertebrae, part of a sacral rib, pelvic fragments, and parts of the humerus, femur and tibia.

MCZ 1260: Fragmentary skull.

MCZ 1261: Fragmentary skull, axis and atlas.

MCZ 1262: Fragmentary skeleton.

MCZ 2043a, 2043b: 2 skulls, jaw fragments, and fragmentary skeletons.