MermaidBrittany
02-27-2013, 07:39 PM
This was on Facebook and I found it to be very interesting. A shark with only teeth on the bottom? Very strange, it almost sounds like it is some sort of science fiction monster.
The buzzsaw jaw of Helicoprion has perplexed scientists for over a hundred years, but new research has finally revealed where its whorl of teeth was located.
As the only remains we have of this strange creature is its whorl of teeth (their skeletons, formed of cartilage, did not fossilize), the 270-million-year-old Helicoprion has gone through many reincarnations. Its discoverer suggested the saw started in the mouth and sat on the nose. Later scientists imagined it not as a spiral of teeth, but as spines located on its back. Next it was moved down to the tail, then back to the upper jaw or the end of the lower jaw. The last time we wrote about it, consensus had placed it inside the mouth toward the back of the throat.
But new techniques and tools have finally solved the mystery. Using a specimen found with remnants of cartilage, the team created a 3D computer model using CT scans. They found that rather than sitting at the end of the lower jaw, the whorl was the jaw. It entirely filled it. What's more, it was all the fish's teeth - Helicoprion had no upper teeth.
"Imagine that... instead of having a tongue, you have this large spiral of teeth. Only maybe a dozen teeth are poking up out of your lower jaw so you can bite," explained Dr Leif Tapanila, one of the new paper's authors. "As the mouth closes, the teeth spin backwards... so they slash through the meat that they are biting into." This motion also forces food inside the mouth.
These findings reveal that Helicoprion ate soft-bodied food such as squid. The team also found that it was not a shark, as previously assumed, but a Holocephalan - a group containing today's ratfish and chimeras. "The main thing it has in common with sharks is the structure of its teeth, everything else is Holocephalan," says Tapanila.
To read the paper: http://bit.ly/XGtFdP (http://www.facebook.com/l.php?u=http%3A%2F%2Fbit.ly%2FXGtFdP&h=XAQHjHuQBAQEl6OQu52Scgc4nucd5as-TUsLMVNcWA2wRMA&s=1)
Image credit: Ray Troll.
http://ivl.imnh.isu.edu/Library/VIP/VIP.html
http://phenomena.nationalgeographic.com/2013/02/26/buzzsaw-jaw-helicoprion-was-a-freaky-ratfish/
http://blogs.scientificamerican.com/running-ponies/2013/02/27/prehistoric-ghost-shark-helicoprions-spiral-toothed-jaw-explained/
http://www.bbc.co.uk/nature/21589719
http://sphotos-a.xx.fbcdn.net/hphotos-ash3/s480x480/156431_10152587362285125_141498634_n.jpg (http://www.facebook.com/photo.php?fbid=10152587362285125&set=a.10150689361175125.699970.456762545124&type=1&relevant_count=1&ref=nf)
The buzzsaw jaw of Helicoprion has perplexed scientists for over a hundred years, but new research has finally revealed where its whorl of teeth was located.
As the only remains we have of this strange creature is its whorl of teeth (their skeletons, formed of cartilage, did not fossilize), the 270-million-year-old Helicoprion has gone through many reincarnations. Its discoverer suggested the saw started in the mouth and sat on the nose. Later scientists imagined it not as a spiral of teeth, but as spines located on its back. Next it was moved down to the tail, then back to the upper jaw or the end of the lower jaw. The last time we wrote about it, consensus had placed it inside the mouth toward the back of the throat.
But new techniques and tools have finally solved the mystery. Using a specimen found with remnants of cartilage, the team created a 3D computer model using CT scans. They found that rather than sitting at the end of the lower jaw, the whorl was the jaw. It entirely filled it. What's more, it was all the fish's teeth - Helicoprion had no upper teeth.
"Imagine that... instead of having a tongue, you have this large spiral of teeth. Only maybe a dozen teeth are poking up out of your lower jaw so you can bite," explained Dr Leif Tapanila, one of the new paper's authors. "As the mouth closes, the teeth spin backwards... so they slash through the meat that they are biting into." This motion also forces food inside the mouth.
These findings reveal that Helicoprion ate soft-bodied food such as squid. The team also found that it was not a shark, as previously assumed, but a Holocephalan - a group containing today's ratfish and chimeras. "The main thing it has in common with sharks is the structure of its teeth, everything else is Holocephalan," says Tapanila.
To read the paper: http://bit.ly/XGtFdP (http://www.facebook.com/l.php?u=http%3A%2F%2Fbit.ly%2FXGtFdP&h=XAQHjHuQBAQEl6OQu52Scgc4nucd5as-TUsLMVNcWA2wRMA&s=1)
Image credit: Ray Troll.
http://ivl.imnh.isu.edu/Library/VIP/VIP.html
http://phenomena.nationalgeographic.com/2013/02/26/buzzsaw-jaw-helicoprion-was-a-freaky-ratfish/
http://blogs.scientificamerican.com/running-ponies/2013/02/27/prehistoric-ghost-shark-helicoprions-spiral-toothed-jaw-explained/
http://www.bbc.co.uk/nature/21589719
http://sphotos-a.xx.fbcdn.net/hphotos-ash3/s480x480/156431_10152587362285125_141498634_n.jpg (http://www.facebook.com/photo.php?fbid=10152587362285125&set=a.10150689361175125.699970.456762545124&type=1&relevant_count=1&ref=nf)