Previously Unknown Ancient Shark Species Found in World’s Largest Cave System Through Fossil Research

Specialists were able to discover a previously unknown ancient spark species at the Mammoth Cave National Park in Kentucky.

New Ancient Shark Species Found

Mammoth Cave's unique environment has enabled the ancient shark fossils to be found in an exceptionally preserved condition. Over 100 different species of ancient cartilaginous fishes, which includes skates, rays, and sharks, have been found in the area.

The Cave system's Mississippian rocks are chunked into different layers known as the Big Clifty Sandstone, the Girkin Formation, St. Genevieve Formation, and St. Louis Formation. The older ones, St. Genevieve and St. Louis, the greatest ancient shark diversity.

The ancient shark species was identified after the discovery of several spoon-like and tiny teeth in the wall of a cave. The discovery was released by the National Park Service (NPS) during National Fossil Day.

The teeth were found as part of a research project called the paleontological resources inventory (PRI) that was coordinated by officials from the NPS Paleontology Program and the Mammoth Cave Park. They were discovered at the St. Genevieve later, making them date back to around 340 to 320 million years ago.

The shark has been named Strigilodus tollesonae, which means "Tolleson's scraper tooth." It was named after Kelli Tolleson, a guide in Mammoth Cave who played a vital role in the PRI. Tolleson was able to find several vital fossil sites in the Cave park. Several of these sites are hard to access.

The species is a type of petalodont, which is an extinct cartilaginous marine fish group that can be found in present-day Europe and US. Interestingly, it is more related to modern ratfish compared to other rays and sharks of today.

The shark's teeth exhibit all possible positions of the teeth of both juveniles and adults. Apparently, the arrangement of the teeth is similar to a fan-like structure. The fossil characteristics show that the shark's way of life may have been similar to modern skates, feeding on smaller fish, worms with soft bodies, bivalves, and snails.

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Mammoth Cave National Park

Superintendent Barclay Trimble of the park explains that teams of paleontologists, geologists, staff, and volunteers have been exerting great efforts in the cave to pinpoint and gather fossils since the start of the PRI in 2019. The research enables a better understanding of the significance, coverage, and management issues linked to the fossil record discovered in the cave system.

Mammoth Cave National park, which houses the world's largest cave system, stretches over 643 kilometers. The rocks of the system go back to the Mississippian time roughly 359 to 323 million years ago when the Pangea supercontinent was forming.

During this period, the land stretch, which now comprises present-day Kentucky and was situated by the equator's south, was full of tropical seas that were shallow.