Orobates pabsti (Berman et al. 2004) Wolfcampian, Early Permian, 1.5m in length, was derived from a sister to Milleretta RC70. Orobates phylogenetically preceded Tetraceratops, Tseajaia, Limnoscelis, Oradectes and Colobomycter.
Distinct from Milleretta the skull of Orobates had a deeper rostrum. The naris was larger. The jugal developed a postorbital process. The teeth were not sharp, but show adaptations to herbivory. The quadratojugal was larger and flared laterally. The mandible was deeper.
A few more cervicals were The vertebrae were broader. The rib cage costal processes. The robust caudal transverse processes turned posteriorly. The tail was short and gracile.
The scapula was taller and more rectangular. The clavicle was more robust. The top of the ilium had a narrow "neck" below the wider dorsal posterior process. The limbs were more robust.
Orobates nested at the base of the Diadectomorpha, a clade that is widely and traditionally considered a pre-reptile clade. Here the entire clade nests in the middle of the new Lepidosauromorpha. Surprisingly this creates an interesting ancestry for all modern lizards, snakes and pterosaurs in which there was a bulky, sluggish plant-eater phase. Limnoscelis appears to have been the only carnivore in this clade.
See the complete tree.