Toothy Spiral Jaw Gave Ancient Sea Predator an Edge An artist's
conception of Helicoprion's bizarre spiral jaw. CREDIT: © Ray
Troll An ancient sea predator had a spiraling whorl of teeth
that acted as a lethal slicing tool, according to new scans of a
mysterious fossil. Helicoprion was a bizarre creature that went
extinct some 225 million years ago. Like modern-day sharks,
Helicoprion had cartilaginous bones rather than calcified ones,
so the only traces it left in the fossil record were weird,
whorl-like spirals of teeth that look quite unlike anything
sharks sport today. The dearth of fossil evidence has led to
multiple attempted reconstructions of what Helicoprion would
have looked like. In some, the tooth whorl is placed on the
upper jaw, curling outward like a spiky elephant trunk. In
others, it's on the lower lip, giving the fish a fearsomely
pouty expression. Researchers have also debated whether
Helicoprion was more like a modern shark or another ancient
group of cartilaginous fish, the chimaera. [25