Navigation Links
Ancient fossils reveal how the mollusc got its teeth
Date:8/22/2012

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
s.bettam@utoronto.ca
416-946-7950
University of Toronto
Source:Eurekalert  

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:
*Name:
*Comment:
*Email:
Related Image:
Ancient fossils reveal how the mollusc got its teeth
(Date:2/3/2016)... PUNE, India , February 3, 2016 ... to the new market research report "Automated Fingerprint Identification ... (Tenprint Search, Latent Search), Application (Banking & Finance, Government, ... 2020", published by MarketsandMarkets, the market is expected to ... estimated CAGR of 21.0% between 2015 and 2020. The ...
(Date:2/2/2016)... , Feb. 2, 2016  BioMEMS ... are primarily focused on medical screening and ... point-of-care parameters. Wearable devices that facilitate and ... freedom of movement are being bolstered through ... human biomedical signal acquisition coupled with wireless ...
(Date:2/2/2016)... NEW YORK , Feb. 2, 2016 Technology ... service presents an analysis of the digital and computed ... Malaysia , and Indonesia ... current trends and market size, as well as regional ... by country and discusses market penetration and market attractiveness, ...
Breaking Biology News(10 mins):
(Date:2/11/2016)... Feb. 11, 2016  Vermillion, Inc. (NASDAQ: VRML ... today announced the formation of the Steering Committee for ... --> Pelvic masses can present physicians ... management. Once pregnancy is ruled out, pelvic masses may ... advanced endometriosis, benign ovarian tumors and gastrointestinal and urinary ...
(Date:2/11/2016)... 2016  Wellcentive today announced it has been ... -based community care organization (CCO) with more ... quality reporting and care management solutions and services. ... of quality managers, analysts and care managers while ... serving FamilyCare members. Oregon ...
(Date:2/11/2016)... Feb. 11, 2016   BioInformant announces the ... Cell Research Products, Opportunities, Tools, and Technologies – Market ... The first ... stem cell industry, BioInformant has more than a decade ... cell market, by stem cell type. This powerful 175 ...
(Date:2/10/2016)... MONTREAL , Febr. 10, 2016 /PRNewswire/ - BioAmber Inc. ... is pleased to announce that Mitsui & Co. Ltd., ... bio-based succinic acid plant, is investing an additional CDN$25 ... equity, increasing its stake from 30% to 40%.  Mitsui ... of bio-succinic acid produced in Sarnia ...
Breaking Biology Technology: