Australothyris smithi (Modesto, Scott and Reisz 2009) Middle Permian, ~3cm skull length, was originally described as a procolophonomorph and a sister to Lanthanosuchus (based largely on the lateral temporal fenestra) along with the Millerosauria (Eunotosaurus+Milleretta RC14). Here it nests as a sister to Feeserpeton, derived from Milleretta RC14.
Distinct from Feeserpeton the skull roof elements have different relative sizes. The parietal was narrower and the postfrontal was larger. Modesto et al. (2009) reported contact between the supratemporal and the postfrontal, which is much larger here than in Feeserpeton. The convex margin of the maxilla and the solid palate distinguish this taxon from its sisters. The orbit was shorter. The teeth were all the same size and shape.