Article

Shark Fossil—"Glikmanius"

prehistoric shark
The Late Mississippian "Glikmanius" found at Mammoth Cave National Park, Kentucky. This ctenacanth shark was approximately over 2.5 feet in length and sported two dorsal fin spines that act as a deterrent to larger predators (like Saivodus) to prey upon them.

Painting by Julius Csotonyi.

A small articulated upper and lower jaw (approximately 11 centimeters long) with elements of the gills and a number of teeth were discovered by NPS Partners from the Cave Research Foundation in the early 1990’s. This specimen was recently examined and identified. The teeth identify this partial skull as a small ctenacanth shark called Glikmanius. What is exciting about this discovery, this represents the first known set of cranial cartilages for this species of shark ever to be identified. In addition, Glikmanius was previously primarily known from the Pennsylvanian (323 to 298 million years ago) and Permian (298 to 251 million years ago) marine sedimentary rocks, making the fossil from Mammoth Cave one of the oldest examples (335-340 million years ago) of this genus.

3D Fossil Shark—Glikmanius
Mammoth Cave National Park, Kentucky

A 3D model. This model shows a rock cliff with a trail and boulders below. The model can be rotated and tilted using a computer interface.

Glikmanius is a species of Late Mississippian age shark (~330 myo). Its fossil is found within the limestone ceiling of a cave passage within Mammoth Cave National Park. Sharks fossils other than teeth are exceptionally rare. Lacking hard skeletal structures, sharks have cartilaginous skeletons, and do not easily fossilize. This fossil preserves a portion of the shark’s head, including portions of the upper and lower jaws and even gill structure. In life, this specimen was about 75 cm (2-1/2 ft) in length.

Last updated: May 3, 2021