Nyctiphruretus acudens (Efremov, 1938) Late Permian ~253 mya, ~36 cm in length, was considered a parareptile and either a procolophonid or a pareiasaur by Säila (2010) who used a matrix from Tsuji (2006). All the sister taxa found by Säila (2010) are sister taxa in the present analysis, but their nesting sites are shifted here. Derived from a sister to Orobates, Nyctiphruretus was a sister to Saurorictus and phylogenetically preceded Sauropareion and Macroleter.
Overall smaller and distinct from Orobates, the skull of Nyctiphruretus had a shorter rostrum, no supratemporal or quadratojugal "horns" and thus a greatly reduced otic notic. It was flatter with a narrower skull roof and orbits open dorsally. One specimen (below) had a ventrally open lateral temporal fenestra on a greatly reduced postorbital area. This further develops in the owenettids and lepidosauriforms. The other retained a long contact between the quadratojugal and jugal. The posterior internal nares (choanae) were not curved medially. The pterygoids contacted each other only anteriorly. A suborbital fenestra was present between the palatine and ectopterygoid. The teeth were smaller and uniform.
The ribs were more gracile. The transverse processes of the anterior caudals were not bent posteriorly.
The clavicle was smaller. The scapula and coracoid were fused. The limbs were more gracile. The ilium was taller and larger. The pubis and ischium were medially directed. The glenoid and acetabulum opened at the lowest points on the pectoral and pelvic girdles. The manus and pes elments were much longer and more gracile.