Cretaceous Shark Dorsal Spine Fossil

Description: This is a fine example of a dorsal fine spine of an extinct shark known as Hybodus. They had a double dorsal fin, with each supported by a sturdy spine. Males of the species had roughened spines between the eyes. Perhaps the rugosity seen here reflects that as well. The taxon was a swift predator which included both fish and belemnites in its diet as shown by fossilized stomach contents which have been found. The genus arose during the Permian and went extinct by the end of the Cretaceous. I have included a life restoration.