Mammoth Cave National Park fossil research identifies new ancient shark species

WNKY Staff,

MAMMOTH CAVE, Ky. – A significant discovery has been made at Mammoth Cave National Park.

MCNP says a new-to-science species of ancient shark was discovered through a Paleontological Resource Inventory (PRI) in the park.

Researchers identified the new species of obruchevodid petalodont, called Clavusodens mcginnisi, through fossil teeth collected deep inside the Ste. Genevieve Formation within the cave.

“The fossil discoveries in Mammoth Cave continue to reveal a wealth of new information about ancient shark species,” said Superintendent Barclay Trimble. “Researchers and volunteers collected samples from the main Mammoth Cave system and from smaller isolated caves throughout the park that have provided new data on previously known ancient sharks and revealed several species that are brand new to science. These discoveries help scientists to better understand the relationship and evolution of modern shark species within this relatively small geographic region.”

Clavusodens mcginnisi Explained

Clavusodens mcginnisi, or “McGinnis’ nail tooth,” was discovered from a number of small teeth found throughout the Ste. Genevieve Formation rock layer in Mammoth Cave National Park. Its name is derived from the shark’s back teeth which superficially look like old iron nails because of their flat crowns and long tooth bases. Nick-named “Chipmunk sharks” for their small size and chisel-like front teeth and crushing back teeth, members of the Obruchevodidae were between 3-4 inches in length. Their small size allowed them to avoid larger predators as they foraged on crustaceans, worms, and small brachiopods found along the sea floor. The species name, mcginnisi, honors retired National Park Service superintendent and naturalist David McGinnis, whose 39-year career started at Mammoth Cave National Park.

Ste. Genevieve Formation Explained

The Ste. Genevieve Formation at Mammoth Cave is a layer of rocks that date back to approximately 340 million years ago. The rocks consist of limestones and shales which formed on the bottom of a warm ocean reef. The majority of fossilized sharks are found in invertebrate hash beds, a rock layer made of skeletal and shell parts of crinoids, blastoids, corals, gastropods, and brachiopods. Prior to the discoveries made at Mammoth Cave over the last several years, no shark fossils were known from the Ste. Genevieve Formation. To date, over 70 species of sharks and other fish have been identified from this geologic layer, including four new species.

To view photos of the discovery, click here.

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