Cranial anatomy, ontogeny, and relationships of the Late Carboniferous tetrapod <i>Gephyrostegus bohemicus</i> Jaekel, 1902

ABSTRACTWe review the cranial morphology of the Late Carboniferous terrestrial tetrapod <i>Gephyrostegus bohemicus</i> from the coal deposits of the Nýřany Basin in the Czech Republic. <i>Gephyrostegus</i> is known from several skulls ranging in length from about 25 mm to about 58 mm (holotype). The narrow skull is about twice as long as wide and shows a well-ossified quadrate and articular, but no evidence of braincase ossification. Autapomorphic features include a pustular ornamentation on some skull table bones, and a plate-like tabular process exhibiting a fine dorsal pitting. <i>Gephyrostegus</i> shares with <i>Bruktererpeton fiebigi</i> (Late Carboniferous, Germany) the presence of low, anteromedially to posterolaterally orientated sharp ridges on the posteroventral surface of the vomer. It shares with seymouriamorphs a rectangular, transverse pterygoid process and closely packed, radially arranged rows of small denticles on the palate. A phylogenetic analysis retrieves Gephyrostegidae (<i>Gephyrostegus</i>, <i>Bruktererpeton</i>) as sister group to Seymouriamorpha, although this wider clade receives low bootstrap support.SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP