Helicoprion

extinct sharks · permian ocean · weird teeth

Spiral tooth saw. Helicoprion had an incredible tooth structure called a tooth whorl, which looked like a circular saw blade made entirely of teeth spiraling outward. Scientists still debate exactly how this strange creature used its spiral teeth to hunt and eat other fish.

Ancient ocean dweller. Helicoprion swam in Earth's oceans between about 290 and 270 million years ago, during the Permian period, long before dinosaurs roamed the planet. This was a time when the oceans were filled with creatures very different from the fish we know today.

Mystery of the spiral. The name Helicoprion means 'spiral saw' in Greek, which perfectly describes its most famous feature. When paleontologists first discovered its fossils in Russia and Australia, they were completely puzzled by how such an odd fish could have survived.

Three known species. Scientists have identified three main species of Helicoprion: H. bessonowi, H. davisii, and H. ergassaminon. Each species had slightly different shapes and spacing of the teeth in their spiraling tooth whorls.

Relative of chimaeras. Helicoprion was actually closer to modern chimaeras (also called ghost sharks) than to regular sharks, even though it looked shark-like. Chimaeras are strange deep-sea fish that still swim in our oceans today.