New insight into the distribution and palaeobiology of the pycnodont fish Gyrodus

The pycnodont fish Gyrodus is reported for the first time from the Lower Cretaceous of Germany based on two lower jaw ele− ments from the Hauterivian and Barremian. The stratigraphic and geographic distribution of Gyrodus is summarized. Gyrodus ranges from the Middle Jurassic to the Early Cretaceous making it one of the longest living pycnodonts. Unambigu− ous Late Cretaceous records of Gyrodus are still missing. Gyrodus displays its widest distribution and greatest taxonomic di− versity in the Late Jurassic. The distribution of Gyrodus implies not only near−coastal mode of life but also a pelagic lifestyle conversely to most other pycnodonts. External body features and function of the unpaired fins support this interpretation.