Picture a shark-like animal, not with rows of razor-sharp teeth like modern sharks, but with a jaw that unfurls into a perfect spiral—like a buzzsaw made of teeth. Meet Helicoprion, the ...

After all, some living sharks had spines or spikes on their bodies, and shark skin itself ... some authorities restored Helicoprion with a static, saw-blade arrangement of teeth at the front ...

"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 ...

The study that nailed down the sharks' saw-tooth arrangement also found that Helicoprion were likely not technically sharks, but close shark relatives called ratfish. But with teeth like that ...

Helicoprion had saws for jaws. That’s really all there was to the 270 million year old ratfish’s dental cutlery. No upper teeth or anything else to slice against – just an ever-growing whorl ...

"Our studies on Helicoprion show it was the largest ... So much the better, because the buzz saw shark had no teeth in its upper jaws at all. With this single row of radial, razor-sharp teeth ...

“Shark-like scales from the Late Ordovician have been found, but no teeth. If these were from sharks it would suggest that the earliest forms could have been toothless. Scientists are still debating ...

With just two rows of teeth, Edestus slid its lower jaw to slice ... before the dawn of the dinosaurs, there lived a shark with a bite unlike any other: Edestus, the scissor shark.

When those teeth come from a relatively ... this opportunity to reevaluate how this strange shark might have fed. Lebedev's 2009 restoration of Helicoprion. Despite the presence of ammonites ...