MAMMOTH CAVE — Rick Toomey spent some time earlier this month talking to guides at Mammoth Cave National Park about shark fossils that have been found inside the cave.
News of the paleontology find made national headlines recently.
“Yesterday, I sat with them for an hour, talking about, among other things, the shark fossils so that they could be better informed to know what we had found and why it was important,” said Toomey, a cave resource management specialist at MCNP.
The guides can use the information to answer visitors’ questions when leading a tour of the cave.
The fossils of approximately 10 different shark species that are now extinct have been found in two different locations inside Mammoth Cave based on the teeth and other skeletal remains that were discovered.
The one that has gotten the most attention is a fossil of the species called Saivodus Striatus, which is an enormously large shark.
“It would have a great white-sized shark,” Toomey said.
But the paleontology find is not new.
The shark fossil was originally discovered in the early 1990s by a group of guides.
Toomey looked at it in 1995 while doing a paleontology inventor, but information about the find wasn’t released either time because MCNP officials didn’t have a lot of information on it or its significance, Toomey said.
When MCNP learned the National Park Service’s paleontology program was working on an exhibit of fossils from caves, they sent a photograph of the Saivodus Striatus to program officials.
At that time, Vincent Tucci, head of the NPS paleontology program, was working with Dinosaur Park paleontologist J.P. Hodnett, who was identifying shark fossils found at the Grand Canyon that were similar in age to those at MCNP.
Hodnett expressed interest in the shark fossils at MCNP and spent three days at the national park in November looking at the various shark fossils, starting with the Saivodus Striatus.
Until November, when Hodnett examined it, MCNP officials did not know what kind of shark it was or how rare and important it was.
When Hodnett saw the Saivodus striatus at MCNP for the first time, he said he was blown away.
“That’s literally how I felt. One, because here’s this like rare fossil that is kind of like paved on the inside of the cave wall and it’s just sitting there,” he said.
Some of the shark’s teeth and portion of the shark’s jaw have been identified.
“It is possible some of the cartilage may represent other portions of the skull, but we cannot tell that yet,” Toomey said.
The Saivodus Striatus fossil at MCNP is spectacular because it is the first evidence of skeletal material for the shark species.
Sharks don’t have bones. Instead, their skeletons consist of cartilage and connective tissue. Cartilage can fossilize, but it is rare that it happens.
“If it gets buried deep quickly and gets isolated away from bacteria that might break it down, it can be preserved long enough for water percolating through to mineralize it and fossilize it,” Toomey said. “It’s much rarer, but it does occur. In this particular case we’ve gotten very lucky and gotten a nice preservation of this jaw portion of this shark.”
The jaw of the Saivodus Striatus is about 2 ½ feet in length.
The shark species became extinct about 320 million years ago. Reasons for the shark species’ extinction is not known. The shark species lived at the edge of 8the Mississippian and Pennsylvanian time periods.
“There was some sort of extinction event that occurred right at the boundary between the Mississippian and the Pennsylvanian (periods), but we’re not 100 percent sure what happened,” Hodnett said.
Finding the shark fossils in the cave tells scientists that there was a shallow sea covering the entire southcentral Kentucky area at one time, and because of that it is possible that similar fossils could be found in the area.
Due to the fossils being exposed to the elements, they don’t show up very well and are hard to find, Toomey said.
“Because the cave dissolved out slowly, the fossils are exposed beautifully in the cave. This gives us a picture of what was happening 330 million years ago all over southcentral Kentucky and not just at Mammoth Cave,” he said.
Hodnett was impressed by the number of shark fossils that were found in the cave. About every foot they would find some type of shark fossil.
“It was ridiculous,” he said.
Hodnett has taken most of the shark fossils from MCNP with him to Washington D.C. where he is trying to determine the various species of the fossils.
The head of the Saivodus Striatus is still in the cave. To remove it would mean cutting a large block of the cave wall out to get it. The shark fossil is in a part of the cave that is not easily accessible and that section of the cave is not part of any tour.
MCNP officials are hoping to use photogrammetry to do a 3-D map and potentially a 3-D restoration of the fossil. The 3-D print of the shark fossil could then be used in an exhibit, Toomey said.
“We are still in the beginnings of this project,” Hodnett said, adding that they are probably a year away from creating any type of exhibit that would be viewed by the public.