Saurorictus australis (Modesto and Smith 2001) SAM PK-8666, skull length ~2.2 cm, estimated total length 15 cm, Late Permian, was considered the most complete captorhinid from that stratum. Here Saurorictus was derived from a sister to Stephanospondylus and Orobates. It nested as a sister to Nyctiphruretus far from the captorhinids.

Much smaller and distinct from Stephanospondylus, the skull of Saurorictus had a deeper premaxilla. The jugal was smaller. The nasals were shorter. The frontals were longer. The posterior skull was not indented.

Saurorictus (left) with phylogenetic successors, Macroleter (center) and Lanthanosuchus (right). Note the steady size increase, the increase in the supratemporal, tabular and quadratojugal horns and the widening of the skull in dorsal view.

The Lanthanosuchia is defined as Varanus, Saurorictus, their last common ancestor and all of its descendants. So, lizards, pterosaurs and snakes also had a flat-headed phase in their ancestry. The lower temporal fenestra in Macroleter and Lanthanosuchus was homologous with later lateral fenestrae in owenettids, etc.

The Lanthanosuchidae is defined as Macroleter, Lanthanosuchus, their last common ancestor and all of its descendants.

Modesto SP and Smith RMH 2001. A new Late Permian captorhinid reptile: a first record from the South African Karoo. Journal of Vertebrate Paleontology 21(3): 405–409.

wiki/Saurorictus