The extraordinarily well-preserved remains of a 330-million-year-old shark’s head have been found embedded in the walls of a Kentucky cave. The discovery, while far from the eastern shoreline, indicates that these caves were once under water and populated by sharks.
“Based on what [paleontologists] see exposed in the cave wall,” they wrote, “there is a lower jaw, indeterminate cranial cartilages, and several teeth to a shark approximately the size of a living great white shark.”
The fossilized remains, Hodnett explained, were identified as belonging to a species called Saivodus striatus, a shark around the size of a modern-day great white. The shark lived during the Late Mississippian period, around 330 million years ago, and may have reached between 16 and 20 feet in length as a fully grown adult.
While describing the excavation of the fossilized shark’s head as “super exciting,” Hodnett was also careful to note that it is a huge challenge to avoid damaging the internal structure of the cave.
The findings, once fully excavated, will be presented to the Society of Vertebrate Palaeontology in Cincinnati in October 2020. Until then, to avoid fossil theft and vandalism, the specific location of the shark’s head within the Mammoth Caves remains a secret.
The fossilized shark head hails from a time when much of North America was under water and was preserved in sediment that impacted over time to form the limestone of the cave networks we know today.
“Kentucky was the happening place to go scuba diving or snorkeling,” Toomey joked, referring to the Late Mississippian epoch.
“We’re starting to get a pretty good idea of what this ocean would have looked like,” he added, referring to the fossils. “What makes it worth it is the thrill of discovery.”
Before the discovery of the Saivodus striatus shark’s head, the Mammoth Cave National Park’s Fossil Shark Research Project had already unearthed approximately 100 different specimens of shark fossils within the cave walls in the form of shark teeth.
“The preservation of these shark fossils is superb,” the team said. “Because the cave is not exposed to external elements such as rain, snow, and wind, the rate of erosion of the limestone in the cave is slow, so fossils tend to be very detailed and mostly intact.”
