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Saturday, March 16, 2013

The Ancient Spiral-toothed Shark

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.

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:  
http://www.bbc.co.uk/)
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.

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/)
With a body length of about 8 meters and a weight of 0.5 tons, Helicoprion recorded as the largest and longest shark that ever lived on Earth. Tapanila said none of the modern sharks that match this record.
Ray Troll's illustration of the Helicoprion, squid-eating fish will feature in a museum exhibition. (Picture from: http://www.bbc.co.uk/)
Helicoprion appearance has long puzzled scientists. Especially about the spiral shape of the teeth that works like a chain saw. "Now we have learned that the shark shape, tooth position of the spiral, as well as how to eat," said Tapanila. *** [BBC | MAHARDIKA SATRIA HADI | KORAN TEMPO 4164]
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