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).
Changing the subject entirely, I took high school German in a small class with two native speakers. I only learned three words of German, and gefübart wasn't one of them. In fact it only gets one hit in google.
Where did you learn German?
Can't imagine how it gets even one, given that I made it up the other night. I noticed you used it correctly, however.
I "learned" German serving two years in Berlin, 1972-1974 for the USAF. Never got very good at it, especially since I was under pressure to get much better at another language for much of that time. What I learned is GI pidgin German.
As in, "My computer is so FUBARed I see no option but to reformat again."
He pissed off someone who complained to a mod.
That's what I thought, but it was interesting to find your neologism used by a native speaker on a German forum.
The only "original" thing I've ever come up with is the Emperor of Utopia, Heili Unlikli.
Vee Gates?
(maybe one of Bill's kids?)
He questioned orthodoxy about the nature of homosexuality in a homosexual agenda thread. He believes that not all homosexuals can be "cured" even if they wanted to be. Apparently openly professing such a belief (which I do not comment on either way) is enough to get you banned. He was accused of promoting the homosexual agenda.
("Ooo-bon")
Thanks for the ping!
Can't we just drive down to the new creationist theme parks and look?
They have living dinosaurs.
That's sad. Sad and unnecessary. Thanks for the info.
And I was teasing YOU for not getting jokes. Just got this one. (Shakes head.)
The thing I regret not doing was traveling to Berlin back then and crossing over into the east. There was an effort going on to persuade us to make trips over there so we could keep established our right to do so. But I wouldn't have been able to take my family, and I'd have had to sew stripes on my Class A's, so I didn't do it.
I finally made the trip to Berlin a couple of years ago. Saw the "Checkpoint Charlie" museum. You'd be hard pressed to find where the wall was in the city, but I think I caught a glimpse of it from the train on the trip through. Apparently that's the only place it still exists is through farm fields outside of town.
One of the most emotional moments in my life was watching the Berliners dancing atop that wall in early 1989, around New Years if I recall. One guy wailing away on a trombone still sticks in my mind. It was a two shirtsleve moment at the time and I can still get a little choked and misty just remembering.
LOL!!
Parrots sometimes get neurotic syndromes (or perhaps skin disorders) which cause them to eventually pluck out all of their own feathers. I've seen quite a few naked parrots as a result of this, and they look very distinctly reptilian. You could do a few close-up videos, and use them as stand-ins for nightmarish dinosaurs in some low-budget remake of "Land of the Lost".
Yes. It must be true! Didn't George Flintstone have a fine feathered pet? Dino!
http://bedrock.deadsquid.com/information/index.php
(Sorry frustrating day at work with some dinosaur brains!) LOL
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