Beneath the forested hills of Kentucky, deep within the vast chambers of Mammoth Cave, researchers have uncovered fossilized remains of two ancient shark species that once roamed the shallow seas some 325 million years ago.

The Fossils That Time Didn’t Forget

Two Fin-tastic finds:

  • Troglocladodus trimblei – Known for its distinctive branching teeth, likely evolved to capture slippery prey.
  • Glikmanius careforum – A predatory brute with powerful jaws, possibly hunting other sharks and squid-like orthocones.

These sharks, part of the ctenacanth lineage (cousins of modern sharks), measured around 10–12 feet in length. Their fossils were preserved in the Ste. Genevieve Limestone, a sedimentary layer that formed when present-day Kentucky was beneath a warm inland sea.

From Darkness, Discovery

The expedition kicked off in late 2019, as part of a resource inventory spearheaded by paleontologists and National Park Service staff. They spotted fossilized shark teeth and fin spines protruding from cave walls—an extraordinary find, considering cartilage rarely fossilizes.

One standout discovery came from Mammoth Cave Superintendent Barclay Trimble, who spotted a key specimen now immortalized in the species name T. trimblei. Fossil expert John-Paul Hodnett joined the team and soon they had identified fossils from over 40 species of ancient cartilaginous fish.

A Time Capsule in Limestone

The preservation is exceptional thanks to the cave’s cool, stable conditions.