Posted on 10/10/2005 3:58:29 AM PDT by PatrickHenry
Biologists examining evidence for the claim that birds evolved from dinosaurs have reached some surprising new conclusions. However, they caution that "the problem of avian origins is far from being resolved." Their analysis is published online October 10, 2005 in the Journal of Morphology, published by John Wiley & Sons, Inc. and available via Wiley InterScience (www.interscience.wiley.com/journal/morphology).
Dinosaurs have long captured the imagination while their relationships have eluded full explanation. Innovative research and a comprehensive consideration of the old can also inspire new interpretations, as researchers recently found when examining the evidence supporting the current theory about feather origins and the relationships of birds and dinosaurs.
All experts agree that birds are related to theropod dinosaurs; however, debate has raged on over whether today's winged creatures are derived directly from advanced theropods, or from an earlier shared ancestor. The current theory supports direct derivation, but recent fossil discoveries in China have led to new questions about the claim. The Chinese discoverers reported finding all stages of feather evolution and ancestral birds, even though the deposits are at least 25 million years younger than those containing the earliest known bird Archaeopteryx.
Researchers, led by Alan Feduccia of the University of North Carolina at Chapel Hill, considered the new findings in the context of the existing literature and furthered the knowledge base with additional experiments. Theagarten Lingham-Soliar of the University of KwaZulu-Natal in South Africa examined the skin of modern reptiles, the effects of decomposition on skin, and the fossil evidence relating to alleged feather progenitors (protofeathers). Richard Hinchliffe of the University College of Wales also examined evidence relating to the tridactyl hand, which is composed of digits 1-2-3 in dinosaurs, the most critical characteristic linking birds to derived theropods.
Feduccia, Lingham-Soliar and Hinchliffe found no evidence for the existence of protofeathers on dinosaurs and no evidence in support of the morphogenesis of the feather from putative filamentous protofeathers. They suggest that 'protofeathers' described on fossil findings "are probably the remains of collagenous fiber 'meshworks' that reinforced the dinosaur integument." Based on their examination of fossilized remains of dinosaurs with no relationship to birds, they suggest that decomposition of skin can lead to patterns resembling feathers.
Birds have been thought to be related to theropod dinosaurs because both groups have a hand reduced to three digits. Theropods are known from fossil evidence to exhibit a hand with digits 1-2-3, the thumb and next two digits. However, the researchers found that the vast majority of evidence supports a 2-3-4 digit identity for bird wings. The bird hand "appears different from that in theropod dinosaurs," they say, and casts doubt upon the theropod derivation hypothesis. Finally, they discuss the significance of the Chinese discoveries with respect to bird origin and flight.
The authors emphasize that the totality of evidence from various branches of science must be included if we are ever to solve the mystery of bird origins and the origin of avian flight. From their careful examination of the available evidence they offer an interim attempt to define morphologically the most salient features of Aves: "Birds are mesotarsal bipedal archosaurs with pennaceous feathers, and a tridactyl avian hand composed of digits 2-3-4."
It is too early to abandon debate on the origin of birds, the authors say. However, mounting evidence suggests that "a possible solution to the disparate data is that Aves plus birdlike maniraptoran theropods (e.g., microraptors and others) may be a separate clade, distinctive from the main lineage of Theropoda, a remnant of early avian radiation, exhibiting all stages of flight and flightlessness."
Article: "Do Featured Dinosaurs Exist?: Testing the Hypothesis on Neontological and Paleontological Evidence," by Alan Feduccia, Theagarten Lingham-Soliar, and J. Richard Hinchliffe, Journal of Morphology, Published Online: October 10, 2005 (DOI: 10.1002/jmor.10382).
Sure....The scientists noticed the middle finger was more extended....Ah, yes...It's a bird!!
Scales are modified feathers.
Scales are modified feathers.And Liberals are modified bird-brains.
Ah. David Drake.
That probably explains my reading of the book...
I'm just wishing Jerry Pournelle would put something new out. C'mon Jerry, have mercy on the fans!
Yes. That's why I try to post (or ping to) serious articles (not from creationist websites, of course) about factual disagreements, academic misconduct, etc.
We've been told repeatedly that scientists don't allow any information to be presented that might conflict with existing theory.
Yes, but we've been told that repeatedly by the same people who keep getting confused by the word "theory."
...and they tasted like chicken!
then they formed democRAT party and and that wiped them out.
Vote the bastRATs out into oblivion!
Fossils with spectacular preservation of dinosaur feathers have turned up since he started doing that and he's still going.
This, for instance:
a closeup of a tuft near the left shoulder of this dromaeosaur:
From the AMNH site.
The specimen, BTW, is considered a near-relative of Archaepteryx, despite it being a dinosaur and Archy being nominally a bird.
I always thiught so. (Eyes glassing over)
I'm hoping Senator Swimmer tries to find out Harriet Miers' position on this question during the confirmation hearings. She's certainly left no paper trail!
Just because you are suspicious, doesn't make you an expert.
I could have told you that!
This morning I had the honor, along with my entire family, to come face to face with a magnificent bull moose, right in my front yard. The only thing I could do was call the family and hope he wasn't feeling too aggressive, cause there wasn't any place for me to hide.
Distance - about 30 ft.
Ol' Bucket Nose was a sight to behold.
So your opinion, based on nothing, is something we should pay attention to?
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