Full reference: E. C. Olson. 1962. Late Permian terrestrial vertebrates, U.S.A. and U.S.S.R. Transactions of the American Philosophical Society, New Series 52(2):1-224
Type specimen: CNHM (FMNH) UR 257, a set of postcrania (femur, vertebrae, parts of ribs). Its type locality is Locality KR (Upper San Angelo Fm.), which is in a Kungurian/Roadian terrestrial shale/sandstone in the San Angelo Formation of Texas.