Concordia cunninghami (Müller & Reisz 2005) Stephanian, Late Pennsylvanian, Carboniferous, 4 cm skull length, was considered the oldest known captorhinid (like Thuringothyris). Concordia was considered distinct from all other captorhinids by the absence of a downturned premaxilla, and the presence of true caniniform teeth, a retroarticular processs, each parietal embayed posteriorly, all palatal bones (including the parasphenoid with short teeth and a short stapes.
Here, derived from a sister to Cephalerpeton, Concordia phylogenetically preceded Thuringothyris at the base of the Captorhinidae and Romeria primus, at the base of all other lepidosauromorphs.
Contra Müller and Reisz (2005), Concordia may have had a slightly downturned premaxilla. They considered the ectopterygoid lost and replaced by the pterygoid, but all sister taxa have an ectopterygoid and one may appear beneath a jugal (see above). Along the same lines, when so many of the teeth are elongated, none can be called caniniform, particularly when this clade appears to be herbivorous at its base. Müller and Reisz (2005) considered the tabular lost, but it is identified here (see above).
Distinct from Cephalerpeton, the skull of Concordia had a flatter, skull with a larger postorbital portion. The orbit and teeth were smaller, the naris was larger. The maxilla lined the base of the naris. The prefrontal and postfrontal nearly touched. The nasals and frontals were wider. The jugal developed a posterior process. The quadratojugal developed a posterolateral "horn". The vomers were very wide to reinforce the maxilla, moving the choanae (internal nares) medially and posteriorly.
The complete reptile family tree is here.