The ancestors of sharks are far more sinister than the sharks we encounter today. Not long ago, a scientists team from Idaho State University, USA, discovered a fossilized giant shark with teeth like a chainsaw. This ancient sharks live in the ocean about 270 million years ago.
The fossil, discovered in Idaho, has a whorl measuring 23 cm with 117 individual teeth. Unlike other specimens, the fossil also includes impressions of the cartilage structures.
|This is a re-creation of|
a Helicoprion, which lived
270 million years ago and is
the only animal ever with a
complete 360-degree spiral
of teeth. (Picture from:
Helicoprion the name of the shark believed to be the early ancestors of sharks that exist today. Then that makes it unique is the ancient shark teeth arranged circular sharp lower jaw. Spiral-shaped teeth that rotate each time the shark ripping and tearing its prey's body.
This conclusion was drawn after scientists reconstruct the shape of the jaw shark Helicoprion with three-dimensional scanner. "The spiral-tooth was in the back of the mouth, right next to the back of the lower jaw joint," said Leif Tapanila, who led the study, on March 6, 2013.
The team of scientists analyzed hundreds of fossil specimens spiral-shaped teeth found in several locations around the world. Only shark teeth preserved, while the shark skeleton made of cartilage, like modern sharks, so it can harden into fossils.
|Helicoprion specimen, preserving cartilages of the mandibular arch and tooth whorl. (a) Photograph and (b) surface scan of fossil, positioned anterior to the right, imbedded in limestone slab. (Picture from: http://whyevolutionistrue.wordpress.com/)|
|Ray Troll's illustration of the Helicoprion, squid-eating fish will feature in a museum exhibition. (Picture from: http://www.bbc.co.uk/)|