preview.tinyurl.com/4dqlhk -> www.newscientist.com/channel/life/dn14892-fossil-reveals-how-the-turtle-got-its-shell.html?feedId=online-news_rss20
Advertising A newly identified fossil could explain one of evolution's biggest mysteries the origin of the turtle's shell. Bone fragments from a 210-million year-old, land-dwelling reptile from New Mexico suggest that the earliest turtles didn't have much of a shell at all. Over millions of years, rows of protective armour plates gradually fused together and to the reptile's vertebrae, eventually creating a complete shell.
Spencer Lucas, of the New Mexico Museum of Natural History and Science in Albuquerque, discovered a neck-bone fragment of the new reptile more than a decade ago, but its provenance remained debatable because the skeleton was so small, Joyce says. However, recent erosion revealed enough pieces of Chinlechelys tenertesta Latin for thin-shelled turtle to remove any doubt. Unlike turtle fossils dating from the later Jurassic era "they're so common people stopped collecting them," Joyce says Triassic turtles are few and far between. That's probably because they lived on land, where fossilisation is far less likely to happen, he says. The new animal is about 30 centimetres long, with a shell only a millimetre wide. "This one's by far the thinnest ever found," Joyce says. More importantly, the reptile's dorsal ribs aren't fully fused to its shell or carapace as is the case in later fossils and in modern turtles.
Guillermo Rougier, at the University of Louisville in Kentucky, who uncovered the first Triassic turtles in northwest Argentina. These and other early turtles had already gained their carapaces and offered few clues as to its origin. C tenertesta, on the other hand, points to the body form that must have given rise to the shell. "This new guy is an animal that belong to the lineage of turtles, it's a proto-turtle in a way," he says. Exactly why turtles evolved their shell remains a mystery, Joyce says. A full shell might offer added protection and stability. And the proof could be in the pudding their body plan is the world's oldest, changing little over 200 million years. "For some reason just being a turtle is an idea that came along and just really works," he says.
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VIEW THREAD >> Fossil Reveals How The Turtle Got Its Shell By John Wood Ph. d Wed Oct 08 18:57:48 BST 2008 The fossil doesn't "reveal" anything. The interpretation is entirely in the eye of the beholder. There is no proof that the first creature gradually evolved to become the modern turtle. This is typical of the pseudoscience of paleontology trying to pass off speculation as fact.
REPLY Fossil Reveals How The Turtle Got Its Shell By Rich Townsend Wed Oct 08 21:14:31 BST 2008 What is your explanation, John? Of course we can't prove that creature A evolved into creature B - that will never be possible. Not all animals are fossilized, there will always be gaps. The way I see it, this creature is potentially filling a gap in the evolutionary story. How do you explain that more and more fossils are being found that appear to fill gaps?
By Mike Wed Oct 08 20:04:49 BST 2008 I agree with the previous poster even though I think he came across as closed-minded. Here is another explaination as to why the turtle has a shell: The god Zeus got married and all the animals were invited. "If you would rather be at home than come to my wedding, then you can carry your home on your back wherever you go!" Some people may prefer one or the other explaination, or neither, but only one explaination makes a great bedtime story to a 5 year old! When it really comes down to it, it doesn't really matter, and as a society we should be researching more important projects.
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