The world’s only animal, past or present, with a complete 360-degree spiral of teeth was Helicoprion, which sliced into prey like a buzz saw.
This shark-like fish, which lived 270 million years ago, is described in the latest issue of Biology Letters. It had one of the most unusual mouths and sets of teeth in the animal kingdom.
"When the animal closed its mouth on prey, the spiral of sharp teeth rotated backwards, like a circular saw, and slashed through the meat,” lead author Leif Tapanila, an associate professor in the Department of Geosciences at Idaho State University, told Discovery News.
Tapanila is also the research curator and head of the Earth Sciences Division at the Idaho Museum of Natural History. For the study, he and his colleagues took the first ever 3D images of Helicoprion remains.
Scientists have puzzled over this animal for more than a century, given its highly unusual "tooth whorl.” The new research sheds light on what this prehistoric marine species looked like, what its ancestry was and how it behaved.
"Helicoprion looked a lot like a big-bodied modern shark, but it had a very unusual mouth,” Tapanila said. "An arc of 15 to 18 serrated teeth were exposed in the center of its lower jaw, and it had no protruding teeth in the upper jaw.”
The buzz saw-looking tooth whorl had two functions, the researchers determined. The outermost part anchored the teeth for biting, while the rest of the inner spiral was designed to house the old and previously used teeth from when the animal was younger.