Helicoprion, also known as the “buzzsaw shark,” is a type of ancient fish that lived 290 million years ago during the Permian Period. Some of the world’s bestHelicoprionfossils have been found in Idaho, and they have also been discovered in Russia, Australia, and China.Helicoprionwas not a true shark, but rather a member of a related group called the eugeneodontids, whose closest living relative is the ratfish.Helicopriongrew over 30 feet long and was a powerful predator. It probably ate fish and cephalopods, using its unique jaw to rip and slice through its prey.
Helicoprionhad unique teeth, which grew in a whorl shape somewhat like a circular saw blade. This is different from any other fish, prehistoric or modern. The tooth whorl continued to grow over the animal’s lifetime. Newer and larger teeth appeared at the back of the mouth, while older, smaller teeth spiraled into the lower jaw. A hard plate on the upper jaw gave the tooth whorl a surface to press against for cutting.