Navigation Links
Ancient fossils reveal how the mollusc got its teeth

TORONTO, ON The radula sounds like something from a horror movie a conveyor belt lined with hundreds of rows of interlocking teeth. In fact, radulas are found in the mouths of most molluscs, from the giant squid to the garden snail. Now, a "prototype" radula found in 500-million-year-old fossils studied by University of Toronto graduate student Martin Smith, shows that the earliest radula was not a flesh-rasping terror, but a tool for humbly scooping food from the muddy sea floor.

The Cambrian animals Odontogriphus and Wiwaxia might not have been much to look at the former a naked slug, the latter a creeping bottom-dweller covered with spines and scales. Despite the hundreds of fossil specimens collected from the Canadian Rockies by the Royal Ontario Museum, scientists could not agree whether they represented early molluscs, relatives of the earthworm, or an evolutionary dead-end. Smith, a PhD candidate in Uof T's Department of Ecology and Evolutionary Biology and author of a study published this week in Proceedings of the Royal Society B, employed a new, non-destructive type of Electron Microscopy to reveal the new details.

"I put the fossils in the microscope, and the mouth parts just leaped out," says Smith, a PhD candidate in U of T's Department of Ecology and Evolutionary Biology. "You could see details you'd never guess were there if you just had a normal microscope."

After examining some 300 fossils, Smith was able not just to reconstruct the mouthparts, but work out how they grew. "The fossils are squashed completely flat, which makes them really hard to reconstruct in 3D," says Smith. "I surrounded myself with micrographs of the mouth parts and lumps of plasticine, and spent weeks trying to come up with a model that made sense of the fossils."

The new observations demonstrated that the mouthparts consisted of two to three rows of 17 similarly-shaped teeth, with a symmetrical central tooth and smaller teeth on the edges. The teeth would have moved round the end of a tongue in the conveyor-belt fashion seen in molluscs today, scooping food algae or detritus from the muddy sea floor. By establishing how the teeth were arranged, moved, grew, and were replaced, Smith was able to demonstrate that they formed a shorter and squatter forerunner to the modern radula.

"When I set out, I just hoped to be a bit closer to knowing what these mysterious fossils were," says Smith. "Now, with this picture of the earliest radula, we are one step closer to understanding where the molluscs came from and how they became so successful today."

The findings are reported this week in the paper "Mouthparts of the Burgess Shale fossils Odontogriphus and Wiwaxia: implications for the ancestral molluscan radula".

Contact: Sean Bettam
University of Toronto

Related biology news :

1. Melting glaciers, enough sand to bury London, and ancient ecosystem engineering
2. Ancient civilizations reveal ways to manage fisheries for sustainability
3. Ancient whale species sheds new light on its modern relatives
4. Ancient Egyptian cotton unveils secrets of domesticated crop evolution
5. Ammonites found mini oases at ancient methane seeps
6. New coelacanth find rewrites history of the ancient fish
7. LSU research finds orangutans host ancient jumping genes
8. Whale population size, dynamics determined based on ancient DNA
9. Ancient giant turtle fossil revealed
10. Like curry? New biological role identified for compound used in ancient medicine
11. Tongue analysis software uses ancient Chinese medicine to warn of disease
Post Your Comments:
Related Image:
Ancient fossils reveal how the mollusc got its teeth
(Date:6/2/2016)... The Department of Transport Management (DOTM) of ... project, for the , Supply and Delivery of ... Infrastructure , to Decatur , ... Management Solutions. Numerous renowned international vendors participated in the tendering ... selected for the most compliant and innovative solution. The contract ...
(Date:6/1/2016)... Favorable Government Initiatives Coupled With ... Identification to Boost Global Biometrics System Market Through 2021  ... report, " Global Biometrics Market By Type, By ... 2011 - 2021", the global biometrics market is projected ... of growing security concerns across various end use sectors ...
(Date:5/16/2016)... , May 16, 2016   EyeLock LLC , ... announced the opening of an IoT Center of Excellence ... and expand the development of embedded iris biometric applications. ... level of convenience and security with unmatched biometric accuracy, ... identity aside from DNA. EyeLock,s platform uses video technology ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... ... June 23, 2016 , ... Supplyframe, ... of the Supplyframe Design Lab . Located in Pasadena, Calif., the Design ... of how hardware projects are designed, built and brought to market. , The ...
(Date:6/23/2016)... ... June 23, 2016 , ... In a new case report published today ... a patient who developed lymphedema after being treated for breast cancer benefitted from an ... paradigm for dealing with this debilitating, frequent side effect of cancer treatment. ...
(Date:6/23/2016)... , June 23, 2016  Blueprint Bio, a ... discoveries to the medical community, has closed its Series ... Matthew Nunez . "We have received a ... the capital we need to meet our current goals," ... provide us the runway to complete validation on the ...
(Date:6/23/2016)... , June 23, 2016 On ... session at 4,833.32, down 0.22%; the Dow Jones Industrial Average ... 500 closed at 2,085.45, down 0.17%. has initiated coverage ... INFI ), Nektar Therapeutics (NASDAQ: NKTR ), Aralez ... Inc. (NASDAQ: BIND ). Learn more about these ...
Breaking Biology Technology: