The osteichthyan paleofauna of the upper Pierre Shale Group has yielded range extensions for taxa known from its Sharon Springs Formation and the underlying Niobrara Formation, notably with the genera Protosphyraena and Pachyrhizodus . Links are now more apparent with Campanian and Maastrichtian (Late Cretaceous) paleofaunas from the Atlantic and Gulf Coasts of the United States, as with Cylindracanthus and Enchodus . Common elements are to be expected, considering the similarities in their geologic ages and environments of deposition.