Article: A new genus of shark from the Middle Triassic of Monte San Giorgio, Switzerland

Associated material from the Middle Triassic of Monte San Giorgio, Kt. Tessin, Switzerland, demonstrates that the sharks Nemacanthus tuberculatus and Acrodus bicarinatus constitute a single taxon that must be included in a new genus, Acronemus tuberculatus. Finspine structure of Acronemus is distinctly different from that of Nemacanthus monilifer, but does correspond to the general ctenacanthiform pattern. Other features of A. tuberculatus such as tooth structure and placoid scales have previously been reported for Triassic hybodontiform sharks only. A discussion of the orders Ctenacanthiformes and Hybodontiformes concludes the study.