Hipposaurus boonstrai (Haughton 1929, skull length 21cm, length 1.2m) Capitanian, Mddle Permian ~260 mya is the most primitive anomodont. Derived from a sister to Cutleria, Hipposaurus phylogenetically precede Stenocybus and the Anomodontia.

Much larger than its ancestors, Hipposaurus kept the small round skull but had longer, more slender limbs capable of a more erect pose and probably a faster gait. Dimetropus tracks that were originally attributed to a high-walking Dimetrodon, but fits Hipposaurus much better. 

Holotype:
(SAM 8950) is a complete skeleton.
Referred materials:
SAM 9081 distorted skull and postcranial elements, type of H. major\
CGP/1/66 (Skull)
WB123 (skull, mandible)

Haughton SH 1929. On some new therapsid genera: Annals of the South African Museum 28(1):55-78.

Boonstra LD 1952. Die Gorgonospier-geslag Hipposaurus en die familie Ictidorhinidae: Tydskr. Wet. Kuns 12:142-149.

wiki/Hipposaurus