New Ancient Shark Species’ Fossils Discovered
On Monday (7/28/25), Ancient shark fossils were discovered in Mammoth Cave National Park, KY
(Kentucky) by Jay Wright, Rick Olson, and Rick Toomey. They were found as fossils due to Kentucky’s abundance of exposed sedimentary rocks, which helped preserve them.
The fossils identified a new species of ancient (extinct) shark, which was then named Macadens olsoni. Macadens olsoni is notable for its unique tooth whorl, which is a curved row of teeth designed for crushing small sea creatures.
This ancient shark was no giant, and only grew about the length of a school ruler (approx. 30cm) and feasted on mollusks and worms. The fossils of Macadens olsoni were found in the Ste. Genevieve Formation, which dates back approximately 340 to 335 million years.
Superintendent Barclay Trimble stated, and underscores the importance of preserving and studying our natural history.”
and also added, “The fossil discoveries in Mammoth Cave continue to reveal a wealth of new information about ancient shark species,”
“Researchers have collected samples from the main Mammoth Cave system, and have been able to provide new data on previously known ancient sharks, while also discovering brand new species to science.”
Some examples of species are: cave cricket (Hadenoceus subterraneus), various bat species (the extinct Stock’s vampire bat), Shark species (Such as the one we’re talking about, Macadens olsoni), and more.
The rocks of Mammoth Cave formed around 320-360 million years ago and were once a shallow saltwater sea, known as the Mississippian Sea. The cave system itself is much younger and had only formed approximately. 10-15 million years ago, when water from rivers and streams on the surface had sunk into the rock and carved out the cave’s passages found today, according to NPS. (National Park Service News)
While the exact length of Mammoth Cave is unknown, explorers have mapped out more than 426 miles (686 kilometers) of it, and are still uncovering new passages. It also hosts a treasure trove of ancient fish fossils, with more than 70 different long-lost species having been identified within its walls so far.
References:
https://www.bbc.co.uk/newsround/articles/c15l4gn08vdo, https://www.livescience.com/animals/extinct-species/ancient-shark-discovered-deep-inside-worlds-longest-cave-system,
https://www.nps.gov/maca/learn/news/mammoth-cave-national-park-discovers-another-new-species-of-ancient-shark.htm,
https://www.nps.gov/maca/learn/news/fossil-research-identifies-new-shark-species-at-mammoth-cave-national-park.htm#:~:text=%E2%80%93%20A%20new%2Dto%2Dscience,from%20deep%20inside%20the%20Ste.