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Re: Dinosaurs and birds



Mike Keesey wrote:

_Archaeopteryx_ is probably not ancestral to modern birds, but it's probably fairly similar to some actual ancestor in many ways. In most ways it's a good ancestor model.

Yes, most models that provide a hypothetical pathway for the evolution of avian flight use _Archaeopteryx_ as the prototype for how later birds came to fly. There's no phylogenetic or ecomorphological evidence to overturn that assumption, AFAIK.


Yes, but (last I heard) he also calls any arboreal, volant dinosauromorph a "bird", and his argument is almost more ecological than phylogenetic. I.e., he doesn't disagree radically with "normal" phylogenies (well, maybe in a few areas, but that's not entirely relevant to the basic idea), but he thinks the lineage leading to modern birds was arboreal and volant for a long time before _Archaeopteryx_, and that most Mesozoic dinosaurs we know are secondarily terrestrial and nonvolant (as well as a few Cenozoic ones of course!).

This leads me to ask, are there any arboreal, volant dinosauromorphs aside from birds? Microraptorans, while not avians, are darn close to birds; they were probably arboreal, and maybe volant (biplane-style). I'd be willing to bet that basal oviraptorosaurs were arboreal too. But that's about it. I have trouble believing that the first sauropods lived in trees, or even the first tyrannosaurs. Then again, as Mike Taylor says, "I have a hard time believing" is not admissable evidence. :-)


I've heard that Mr Olshevsky is self-publishing a book (or books) about "BCF". Then again, I've been hearing this for quite a while now.

This argument hasn't found a lot of support, although some think flight may have originated somewhere in basal _Maniraptora_, at least.

Yep, that's the gist of Greg Paul's idea, as per PDW and DA. "BCF" is far, far more radical, and has far, far less support.


(Then again, some don't even think _Archaeopteryx_ was volant.)

Is the non-flying _Archaeopteryx_ idea still around?

Cheers

Tim

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