The oldest records of the stem amniote Discosauriscus (Seymouriamorpha, Discosauriscidae) from the European Carboniferous-Permian boundary

The skeletal remains of early tetrapod Discosauriscus (Seymouriamorpha) are known from the lower Permian deposits of the Central and Western Europe. We describe here two specimens of Discosauriscus : one from the Czech Republic ( D. pulcherrimus ) and the second from Germany ( D. cf. pulcherrimus ). Discosauriscus pulcherrimus is represented by the complete skull and partial anterior postcranial skeleton, and represents the oldest record of this species from the Czech Republic. To identify the diagnostic characters of D. pulcherrimus , we used the high-resolution X-ray microcomputed tomography. This enabled us to identify all three characters typical for this species, in contrast to the morphology of the contemporaneous D. austriacus . The discosauriscid from Germany, known on the basis of the postcranial skeleton ( Discosauriscus cf. pulcherrimus ), represents the first record of the genus Discosauriscus from the Upper Carboniferous. •