The researchers were "stunned" when they discovered the remains of a huge fossilized shark head in the walls of a cave in Kentucky. The remains of the ancient animal were found in the Mammoth Cave National Park, which according to the National Park Service is the longest cave system in the world. The shark fossil discovered by scientists investigating the cave system is believed to be around 330 million years old, according to John-Paul Hodnett, paleontologist and program coordinator at Dinosaur Park in Maryland. Scientists sent Hodnett photos of the results so that it could help them identify them. He was able to identify most of the fossils, but what made him "really excited" was seeing a number of shark teeth associated with large sections of fossilized cartilage. Shark skeletons are made of cartilage, which does not fossilize as well as bone, therefore it is rarely preserved. Preserved cartilage can only be found in select locations around the world. Shark teeth, on the other hand, are among the most common fossils found across the planet since they are replaced during the life of the animal. Eventually Hodnett visited the park to examine the fossils and, although he did not discover a complete skeleton, he found parts of a head that belonged to a prehistoric shark, which he believed was the size of a modern great white shark. Based on what has been exhibited in the cave wall, he identified a 2 1/2 foot long lower jaw, teeth and other cartilages belonging to this great shark and about 100 extremely detailed teeth of other shark species.
“What we saw in the cave was fantastic because only from the shape of the jaw will we be able to find out more about how this species lived and we can adapt it to the shark family tree more accurately,” Hodnett said. Based on what has been exhibited in the cave wall in Mammoth Cave National Park, John-Paul Hodnett identified a 2 1/2 foot long lower jaw of an ancient shark. On the right is the posterior end of the jaw where it attaches to the head. On the far left is the “chin” of the barely protruding jaw. In the middle are teeth and pieces of other cartilage. The ladder bar has a length of 10 centimeters. JOHN-PAUL HODNETT The team determined that the shark belonged to a species called Saivodus striatus, which lived during the geological period of the late Mississippian, over 330 million years ago. Most of the shark fossils discovered by researchers come from a layer of rock that extends from Missouri to Virginia. However, this is the first time that the presence of sharks has been documented. “Mammoth Cave has a rich record of fossil sharks and there is still much more to discover,” said Hodnett.