Dino-Bird evolution for Aggie

Knowing that Aggie and I share an interest in bird evolution I saw this and thought of him.



Birds fly over the sea after sunset. Palaeontologists have fired a broadside over a fossil which is the cornerstone evidence to back the theory that birds descended from dinosaurs.


Palaeontologists have fired a broadside over a fossil which is the cornerstone evidence to back the theory that birds descended from dinosaurs.
The row focuses on Sinosauropteryx, a fossil found in 1994 by a farmer in Liaoning province, northeastern China, a treasure trove of the Early Cretaceous period some 130 million years ago.

About the size of a turkey, the long-tailed meat-eating dino was covered with a down of fibres that, its Chinese researchers claimed, were primitive feathers.

That claim had the effect of a thunderclap.

Although the "feathers" were clearly not capable of flight, their existence dramatically supported a theory first aired in the 1970s that birds evolved from dinosaurs. As a result, a once-outlandish notion has become the mainstream concept for the ascent of Aves, as birds are classified.

But a new study, published by a team led by South African academic Theagarten Lingham-Soliar at the University of KwaZulu-Natal, sweeps away the proto-feathers claim.

The two-branched structures, called rachis with barbs, that were proclaimed as early feathers are quite simply the remains of a frill of collagen fibres that ran down the dinosaur's back from head to tail, they say.

More here: Can't copy the link. I'll post it in next post.

http://www.physorg.com/news99114780.html

Feathers are made of keratin and collagen. Certainly some sort of fibrous collagen structure is a not-surprising precursor.

I don't really see the problem. Instead of being primitive feathers, they are even more primitive pre-feather structures.

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"I'd take the awe of understanding over the awe of ignorance any day." - Douglas Adams

"Isn't it enough to see that a garden is beautiful without having to believe that there are fairies at the bottom of it too?" - Douglas Adams

"Skaloopdidit" - Keeping Skaloop as the first cause until science can rule him out.

"I'd be a theist if it weren't for God." - Me

Also, even if you ignore that this is still proof for evolution to have occured, we still have to aknowledge that this test has to be further validated before it outweights the first study. Newer doesn't mean better, or more likely right, as long as there is only one study for it.

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Your link isn't working, but I know the study you're referring to. It's being discussed at Gondolend, a paleontology forum where I'm a member.

The usual claim about these structures being collagen fibers is that they aren't a skin covering at all; that they're some sort of result of decomposition after the animal died. This claim has been around for at least ten years, and I thought most people considered it to be disproved by now. On the counterslab of Sinosauropteryx (the other half of the rock that was split to reveal the fossil), it's possible to see these fibers extending down the animal's side, which isn't consistent with the original claim about fibers of collagen having settled around the animals edges as its skin decomposed. I haven't seen this new study, though, so it's possible that it's claiming something different from this.

Scott Hartman, a professional paleontologist who posts at Gondolend, announced this morning that he's read the actual study and that in his opinion it's "awful". He's going to post something soon on a paleontology mailing list about what's wrong with it; I'll post a link to that here if I find it.

Incidentally, there's something else to keep in mind about this study, if you're considering it as evidence against evolution: Sinosauropteryx was the only known feathered dinosaur when it was discovered in 1996, but now there are around a dozen of these known, some of which have feathers that are a lot more advanced and easily recognizable than those on Sinosauropteryx. So at this point, whether or not Sinosauropteryx was feathered doesn't have much of an impact on this particular line of evidence for the relationship between dinosaurs and birds.

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The interesting thing about the structures on Sinosauropteryx is that similar features are seen on other birds and theropod dinosaurs from the area (many of which are undoubtedly feathers). If these structures were really degraded collagen, we would expect to see them on the turtles, lizards, and fish from the area -- but we don't.

I think this is just another poor paper written by a poor scientist. I've read papers by the senior author before (on mosasaurs) and his conclusions are often tenuous at best. His work often draws a lot of published critical response in academia.

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We can allow satellites, planets, suns, universe, nay whole systems of universes, to be governed by laws, but the smallest insect, we wish to be created at once by special act.

-- Charles Darwin

http://dml.cmnh.org/2007May/msg00416.html

I am finally back, sorry it has been so long.

I was not presenting this as evidence against evolution, I just had previously discussed the subject with Aggie and knew of his interest in this.

Aggie: I guess you had already seen it. Oh. well.