Posted on 06/15/2006 11:39:26 AM PDT by PatrickHenry
Five fossil specimens of a near-modern bird found in the Gansu Province of northwestern China show that early birds likely evolved in an aquatic environment, according to a study reported today in the journal Science. Their findings suggest that these early modern birds were much like the ducks or loons found today. Gansus yumenesis, which lived some 105 to 115 million years ago during the Early Cretaceous period, took modern birds through a watery path out of the dinosaur lineage.
The report was co-authored by Peter Dodson of the University of Pennsylvania and his former students Hai-lu You of the Chinese Academy of Geological Sciences, Jerald Harris of Dixie State College of Utah and Matthew Lamanna of Carnegie Natural History Museum in Pittsburgh.
"Gansus is very close to a modern bird and helps fill in the big gap between clearly non-modern birds and the explosion of early birds that marked the Cretaceous period, the final era of the Dinosaur Age," said Peter Dodson, professor of anatomy at Penns School of Veterinary Medicine and professor in Penns Department of Earth and Environmental Sciences. "Gansus is the oldest example of the nearly modern birds that branched off of the trunk of the family tree that began with the famous proto-bird Archaeopteryx."
Gansus yumenensis takes its name from the Gansu region, where it was found, and the nearby city of Yumen. According to Dodson, Gansus is something of a lost species, originally described from a fossil leg found in 1983, but since largely ignored by science. The five specimens described by Dodson and his colleagues had many of the anatomical traits of modern birds, including feathers, bone structure and webbed feet, although every specimen lacked a skull.
"It appears that the early ancestors of modern birds lived lifestyles that today we would stereotype as being duck-like, heron-like, stork-like, loon-like, etc.," said Jerald Harris, director of paleontology at Dixie Sate College of Utah. "Gansus likely behaved much like its modern relatives, probably eating fish, insects and the occasional plan. We won't have a definitive dietary answer until we find a skull."
The skeletons, headless as they are, offer plenty of evidence for a life on the water. Its upper body structure offers evidence that Gansus could take flight from the water, like a modern duck, and the webbed feet and bony knees are clear signs that Gansus swam.
"Webbed feet is an adaptation that has evolved repeatedly in widely separate groups of animals, such as sea turtles, whales and manatees, and would only hinder climbing or landing in trees," Harris said. "The big bony crest that sticks off the knee-end of their lower leg bones are similar to structures seen in loons and grebes. These crests anchor powerful muscles needed for diving under water and swimming."
According to Harris, these adaptations all demonstrate how the Gansus branch of the family tree, the structurally modern birds called ornithuromorphs, split from the enantiornitheans (or "opposite birds"). Enantiornitheans were among the feathered fossils found in northeastern China during the 1990s.
"The enantiornitheans had the best adaptations for perching, so they were able to dominate the ecological niche that we would associate with songbirds, cuckoos, woodpeckers or birds of prey," Harris said. "Gansus appears to have had adaptations for a lifestyle centered around water, based on things like the proportions of the leg and foot bones."
While the enantiornitheans are now long gone, their perching lifestyle has now been taken over by the descendents of birds like Gansus. What remains a mystery for now, according to the researchers, is how the amphibious lifestyle of birds like Gansus helped enable them to survive the cataclysmic end of the dinosaurs 65 million years ago.
Funding was provided by the Discovery Channel (Quest program) and the Science Channel, the Carnegie Museum of Natural History, Dixie State College, the Chinese Geological Survey of the Ministry of Land and Resources of China and the Gansu Bureau of Geology and Mineral Resources.
If you want to debate their phylogenies, why don't you email them.
Here, let me finish the sentence for you:
"How you take doesn't make one bit of difference to me...."
"....since I'm really just here to troll, not to actually contribute anything to the discussion."
And your reply is exactly what I predicted.
You trolls are SOOOOO predictable.
I get it, use the word "plesiomorphic" when describing the features of allegedly gabillion-year-old specimens.
I wonder if the 11 million year old "extinct" Laotian rock rat, recently found in a meat market and other places, has any "plesiomorphic" features.
another one here
(but i cannot get the source to transmit the photo)
http://www.geotimes.org/current/WebExtra061506.html
interesting that these photos show the almost entire skeleton....together, not scattered (as i had conjectured)...
*sigh* No, you don't get it. Plesiomorphic refers to traits not found in a more derived group. You can't describe this bird as a duck because it has traits that no duck has.
"You will find what you are looking for. When you know what the results are you need, there are many examples of otherwise good scientists who manage to FIND those results, whether they are correct or not. Just human nature."
The power of perception is a fascinating topic. Humans are way more subject to it than most people even realize.
I have an article somewhere (can't find it right now) which discusses a research project where they took 50+ wine experts and gave them a test. They mixed white wine with red food coloring and put it in a bottle with a red wine label. About 80% of the experts said that it was red wine and they said that it even had the different constituent flavors found in red wine.
These experts were convinced because of their prior perceptions, not because of the current reality. I'm sure this would never happen in science, though. </sarcasm>
Likewise I'm sure it never happens in matters people consider of great import to their religion. [/sarcasm]
"Likewise I'm sure it never happens in matters people consider of great import to their religion. "
On the contrary, it applies to all people. Religious people definitely exhibit this behavior.
My observation from these threads is that scientists consider themselves immune from such influences, and that's where I believe they deceive themselves.
Yes, understandably creationists would object to any such words as "primitive" and "derived." I think your approach is the most honest one. There is another article posted saying that there is nothing unusual about this bird and it is just a duck exactly like modern ducks. This is definitely dishonest if we examine the skeletal data.
the vertebrae is interesting, are all birds today, solely heteroceolous?
It appears that this is a necessary but not sufficient trait to be classified as a modern bird.
If any of you care, and I'm sure you don't, check out this link: ŚaṃkaraÂ’s Principle and Two Ontomystical Arguments
Excerpt:
We thus have to characterize the sort of seeming to which the principle applies while avoiding the problem of possible misidentification of oneÂ’s experience. Consider another more difficult case. Suppose that it is an essential property of living elephants to be have heads, but that it appears to me that I am faced with a living headless elephant. If ŚaṃkaraÂ’s principle applies, it would follow that headless living elephants are possible, which is false. To take care of this, we introduce the more technical locution “really seems”. “An x really seems to s” is true if and only if s would be correctly identifying the content of a single phenomenal experience of hers if she were identifying it to be an x. In the case of the apparent perception of a living headless elephant, I am presumably misidentifying the object of my experience as an elephant, since anything that is living and headless cannot be an elephant and anything that appears living and headless should not be identified as an elephant. I am making a mistake about what it is that I seem to perceive. I should instead say “An elephant-like living headless animal really seems to me”, and of course an elephant-like living headless animal is possible.
LOL! Cajun can be some mighty good eatin'.
Because evolution suggests that anything is possible, if the appropriate mutations occur and if the result is viable and has an opportunity to succeed in breeding within the population.
Surely, a theory that says that land creatures could eventually live under water, and water creatures could walk on land, can support the postulate that some species may find advantage in not having heads.
Maybe the shock is that there is so little diversity in the structure of living creatures, given the time frames involved and the tremendous changes observed in life over that time. A one-celled organism became a creature with a head, and you think it odd to postulate that a headless creature might evolve?
But in truth, see my other recent post. I've no real time for any further attempts at opening minds to the infinite possibilities of non-designed life.
"Because evolution suggests that anything is possible,..."
No it doesn't.
There most certainly are headless creatures. Molluscs and sponges are examples.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.