This paper describes a new species of lungfish, Ptychoceratodus roemeri, sp. nov., based on 25 tooth plates from the Upper Triassic (Carnian) freshwater sediments of the Krasiejów locality, in Poland. Two vomerine teeth and numerous scales were also found associated with the tooth plates. Specific variations in Ptychoceratodus tooth plates are analyzed together with morphological evidence of ontogenetic changes among selected species. This study permits the discrimination between diagnostic, systematic characters and those affected by ontogeny. The new species together with nine other ptychoceratodonts from the Triassic of Europe are compared in order to assess their interrelationships. On the basis of morphological and biometrical comparisons, P. roemeri, sp. nov., is most closely related to P. concinnus from the Lehrberg Beds in Germany.