[_ Old Earth _] Discovery Raises New Doubts About Dinosaur-bird Links

[Crying Rock]

Discovery Raises New Doubts About Dinosaur-bird Links

ScienceDaily (June 9, 2009)  Researchers at Oregon State University have made a fundamental new discovery about how birds breathe and have a lung capacity that allows for flight – and the finding means it's unlikely that birds descended from any known theropod dinosaurs.

http://www.sciencedaily.com/releases/20 ... 092055.htm

Quick, D. E., and J. A. Ruben, 2009, Cardio-pulmonary
anatomy in theropod dinosaurs: Implications from
extant archosaurs. Journal of Morphology. Published
Online, May 20, 2009, DOI: 10.1002/jmor.10752.

http://www3.interscience.wiley.com/jour ... 1&SRETRY=0

 

[Barbarian]

There are some similarities between birds and dinosaurs, and it is possible, they said, that birds and dinosaurs may have shared a common ancestor, such as the small, reptilian "thecodonts," which may then have evolved on separate evolutionary paths into birds, crocodiles and dinosaurs. The lung structure and physiology of crocodiles, in fact, is much more similar to dinosaurs than it is to birds.

This one comes up from time to time, mostly from followers of Allan Feduccia and Stors Olsen, both of whom are ornithologists who strongly dislike the notion of birds as evolved dinosaurs. Since this article cites a Feduccia claim of bird fossils preceding dinosaurs, it's likely that is where this news story came from.

It's not much comfort for creationists, though. It merely means that birds are a sister group to dinosaurs, both having evolved from thecodonts, instead of birds being an offshoot from the dinosaur clade. The fact that T-rex heme is more like that of birds than of living reptiles makes that somewhat unlikely, but not impossible.

If you want to pursue this thinking, or just want to learn a great deal about the evolution of birds, I would strongly reccomend Feduccia's The Origin and Evolution of Birds. I don't think he's right about everything, but he's pretty good.