Sunday, 31 January 2010
A feathered dinosaur and a bird ancestor – or perhaps not?
A Confuciusornis fossil. Image courtesy of Wikipedia. Recently, researchers found melanosomes in this bird.
Natural history museums often present birds as the descendants of dinosaurs. This idea has become a Darwinian myth that has lived a life of its own despite studies and evidence that have shown that it is impossible.
The popular press is abuzz with the news of two recent discoveries made in China. Nature published a paper detailing research conducted by Michael Benton, a paleontologist at the University of Bristol, UK, and colleagues on fossilized melanosomes in different animal fossils.
Melanosomes can be found in skin, fur and feathers. Benton and his colleagues looked at birds and dinosaurs. They noticed that Confuciusornis, which is a bird, had two types of melanosomes. They also found one of them on the dinosaur Sinosauropteryx in which no feathers were observed. The researchers think that they saw ”feather-like bristles”, though. They assume that this supports the view that dinosaurs had feathers.
However, not all experts are convinced that they made the correct interpretation. Finding melanosomes might say something about the colour of a dinosaur, but it is a long way to feathers. Alan Feduccia, a biologist at the University of North Carolina at Chapel Hill, disagrees with their view, saying that they "make a leap of faith going from Confuciusornis to Sinosauropteryx."
Science published a paper by Jonah Choiniere of George Washington University, Xing Xu and colleagues on a well-preserved dinosaur of the family Alvarezsauridae. Named Haplocheirus sollers, Science’s Richard Stone said it was 15 million years older than the earliest bird Archaeopteryx.
The researchers did not find any feathers on the earthly remains of Haplocheirus sollers and they did not claim that it was a transitional form between dinosaurs and birds. The missing feathers did not keep the popular media from getting excited, though.
This is interesting since according to physorg.com, ”Mr. Choiniere's research demonstrates that the family Alvarezsauridae evolved in parallel to birds and did not descend from them.” (bold added).
Dinosaur discovery helps solve piece of evolutionary puzzle (w/ Video).(28 January) http://www.physorg.com/news183909269.html
Lundin, Sverker. 2010. The Lost World, Now in Color. ScienceNOW Daily News. (27 January)
Stone, Richard. 2010. Bird-Dinosaur Link Firmed Up, And in Brilliant Technicolor. Science(29 January). http://www.sciencemag.org/cgi/content/short/327/5965/508