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Nov 26, 2008 01:14 PM | 10
Ever wonder how a turtle got its shell? You're not the only one. Evolutionary biologists and paleontologists have long been stumped by the question. But a recently unearthed turtle fossil, the oldest on record, may hold the answer. Researchers report in Nature today that the fossil indicates shells evolved as an extension of turtles' backbones and ribs.
"Its discovery opens a new chapter in the study of the origins and early history of these fascinating reptiles," says vertebrate paleontologists Robert Reisz and Jason Head of the University of Toronto, in a commentary accompanying the article.
Scientist have been in the dark until now because all fossilized turtles previously discovered had complete shells. But this 220 million-year-old fossil is an ancestor of the modern turtle at a stage when its shell was still evolving.
An international team of paleontologists led by Chun Li of the Chinese Academy of Sciences in Beijing analyzed the 16-inch- (40 centimeter-) long fossil, which was discovered in Guizhou Province in southwestern China. They conclude that the bones belonged to a Triassic turtle ancestor, which they named Odontochelys semitestacea, meaning "toothed turtle with a half shell."
The newly discovered species sported a shelled belly and a little extra bone on its spine, supporting the theory that turtles' shells formed over eons as their backbones and ribs grew. The main competing idea is that hard, bony plates in their skin (such as those in the skin of modern-day crocodiles) fused together.
The authors say that this turtle species probably lived in water and that their stomach shell kept them safe from predators below while they were swimming.
(Turtle fossil photo above courtesy of Institute of Vertebrate Palaeontology and Palaeanthropology, Beijing; Illustration of Odontochelys semitestacea below courtesy of Marlene Donnelly)
Tags:
shell,
vertebrate,
reptile,
evolutionary biology,
evolution,
turtle
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10 Comments
Add Commentagenntucky, if you ever get your GED maybe you would understand
Reply | Report Abuse | Link to thisouch, harsh. I have a degree in computer science...
Reply | Report Abuse | Link to thisdid they teach you humor where you got yours?
@agenthucky; After you have read The Origin of Species by C. Darwin very thoughtfully and critically, please go to www.vengansa.org for follow-up commentary.
Reply | Report Abuse | Link to this@agenthucky; Sorry, that's supposed to be: www.venganza.org
Reply | Report Abuse | Link to thisSarcasm is hard.
Reply | Report Abuse | Link to thisNeat story!
I had an old friend who used to tlsk about eating turtles...he told me 'there is 7 kinds of meat in a turtle!'
Reply | Report Abuse | Link to thisI thought it was ALL turtle meat. My bad.
The way I understood it by the passer downers was that Turtle meat had 7 different "tastes". My favorite was the one part that tasted like turtle...
Reply | Report Abuse | Link to thisowlvee
it's a cool site-and of course a great magazine. Anyone here knows of any other great sites of this nature with a chat forum?
Reply | Report Abuse | Link to thisFascinating. Yes I did wonder about Turtles. Makes sense. Funny how some reptiles turned into birds isn't it? Very cool article.
Reply | Report Abuse | Link to thisAny fossil finds such as this are exciting. Not just because they fill certain gaps in the fossil record, and therefore add to our body of knowledge, but because they stimulate us to reflect upon animals that must have existed, but as yet are undiscovered. Think of all the species that came both before and after this one that evolved over time to become the shelled turtles that are more familiar to us. So many fossils are awaiting discovery.
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