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First of all, a correction. I wrote:
J.P. Garner, G.K. Taylor, and A.L.R. Thomas. 1999. On the origins of birds:
the sequence of character acquisition in the evolution of avian flight.
Proceedings of the Royal Society: Biological Sciences.
The page nubers should be "1259-1266". So the article is 8 pages long, not
1483 pages long. Quite a difference. (I'm not sure where I got "1471-2954"
James Cunningham wrote:
In 4-winged birds, the tip fan is capable of supporting the weight of the
tail, but at first blush doesn't appear suited for also supporting the
weight of the legs, so without the hindlimb feathers those birds would also
have had a a bit of a cg problem.
It is my understanding of such things (which is not that much) is that a
posterior center of gravity (cg) is a problem for pasive (non-powered)
gliders as well as active (powered) fliers.
Note that none of this applies to modern birds with brains evolved for more
unstable flight and without the weight of a long, unfeathered tail.
One curious aspect of avian evolution (at least, curious to me) is that the
shortening of the tail and development of a pygostyle occurred in birds that
had rather long legs (e.g.,_Sinornis_). I think one of Gatesy's papers
discusses this too. So early ornithothoracine birds dispensed with the tip
fan, but kept their "primitive" theropod legs.
Also, wouldn't the long tail-frond and hindwings have interfered with a
P.S. Gatsey & Dial do good work.
That they do.
Phil Bigelow wrote:
Perhaps the new view should instead be considered a third hypothesis,
rather than being considered a replacement that falsified the earlier two
I didn't mean to imply that either the 'ground-up' or 'trees-down'
hypotheses had been falsified. No, what I was trying to say is that many
traditional pre-flight models have been constrained by the perception that
the proavian either spent all of its time on the ground, or all (or most) of
its time in trees. This did not help the formulation of individual