Acleistorhinus pteroticus (Daly 1969) Early Permian, ~3.5 cm skull length was consiered by DeBraga (2001, 2003) to be a Parareptile related to Lanthanosuchus, which is a mismatch. Here Acleistorhinus is derived from a sister to the RC14 specimen of Milleretta and phylogenetically preceded Eunotosaurus.

Distinct from RC14, the skull of Acleistorhinus was further downturned anteriorly. The maxilla ascended to cut off the lacrimla from the naris and to contact the prefrontal. The jugal separated from the squamosal creating a lateral temporal fenestra. The supratemporal was enlarged. The second half of the skull was expanded laterally, rotating the orbits anteriorly for better binocular vision.

Since both Eunotosaurus and Milleretta had expanded ribs, it is likely that Acleistorhinus did so too.

Daly E 1969. A new procolophonoid reptile from the Lower Permian of Oklahoma. Journal of Paleontology 43: 676-687.

DeBraga M 2001. The postcranial anatomy of Procolophon (Parareptilia: Procolophonidae) and its implications for the origin of turtles. PhD thesis, University of Toronto.

DeBragra M 2003. The postcranial skeleton, phylogenetic position and probable lifestyle of the Early Triassic reptile Procolophon trigoniceps. Canadian Journal of Earth Sciences 40: 527-556.

DeBraga M and Reisz RR 1996. The Early Permian reptile Acleistorhinus pteroticus and its phylogenetic position. Journal of Vertebrate Paleontology 16(3): 384–395.

wiki/Acleistorhinus