Redescription of the cranial anatomy of Ariekanerpeton sigalovi (Seymouriamorpha: Discosauriscidae; Lower Permian, Tadzhikistan) highlights new diagnostic features which permit a new skull reconstruction and revised diagnosis. The largest Ariekanerpeton specimens differ from like-sized Discosauriscus, a second member of Discosauriscidae, in showing: oblique anterior margin of tabular ornamented surface; acute, elongate posterolateral corner of supratemporal; postorbital ventrolateral ramus with small anteroventral process and forming oblique suture with jugal dorsomedial ramus; jugal posterior ramus tapering rearward, forming subhorizontal suture with quadratojugal; weak ventral sculpture lateral to pterygoid articular recess; parasphenoid subrhomboidal, with lightly sculptured anterior wedge-like process; more densely arranged denticle rows on top of low radiating ridges on pterygoid palatal ramus. Gill filaments occur in specimens with skull lengths of up to 30 mm. Detailed examination of ontogenetic changes in Ariekanerpeton and comparisons with other seymouriamorphs are presented.

The skull roof, palate and lower jaw of the seymouriamorph Utegenia shpinari (?Upper Carboniferous–Lower Permian; Kurgalin Formation, Kazakhstan) are described in detail, and a new cranial reconstruction is presented. Important features include: skull slightly longer than broad; elongate nasals; deep, elongate posterior cheek region; long, dorsoventrally deep posterior jugal ramus; flat, recurved, blade-like tabular process; denticle-covered anterior ventral part of pterygoid quadrate ramus; transverse pterygoid flange; low radiating ridges with denticle rows on pterygoid and parasphenoid cultriform process; incipient anterior wedge-like process on posterior end of parasphenoid cultriform process; distinct, robust posterolateral processes of posterior plate of parasphenoid. Degree of skull ossification, ornamentation, and absence of ossified quadrate, articular and endocranium suggest that large Utegenia specimens correspond to larval Discosauriscus. In such specimens, dentine infolding extends for almost half of the crown in premaxillary and largest maxillary teeth, as in late larval/metamorphic Discosauriscus. Preliminary results of a regression analysis through some simple skull measurements indicates that, although the preorbital and interorbital regions elongate isometrically relative to the posterior skull table, they do not show a particularly strong linear correlation with the widening of the skull during ontogeny.