Prehistoric 'Shark' Helicoprion Had Saw-Like Spiral Teeth

It's a mystery that has puzzled paleontologists for a century, but scientists are now gaining a better understanding of a bizarre prehistoric fish called Helicoprion.Researchers at Idaho State University led by Dr. Leif Tapanila published new findings concerning the appearance and evolutionary history of the long-extinct 25-foot predator in Biology Letters on Feb. 27.