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Re: The origin of flight: from the water up
----- Original Message -----
From: "Waylon Rowley" <email@example.com>
Sent: Wednesday, March 27, 2002 7:30 AM
> I doubt we can say how pneumatic Archie was just by
> identifying pneumatopores on the bones. Regardless, it
> was still a very light coelurosaur.
It certainly wasn't as pneumatic as most neornithines who have air in their
sternum, furcula, ilia...
> In regards to Dipper wings:
> > Sure? Even stubbier than Archie's?
> Hard to tell from online pics because they all show
> them with wings folded, but Dipper's do appear to have
> smaller wings, or smaller primaries at least.
I'd appreciate a URL.
> If we were talking about tiny
> hummingbird-sized maniraptors, FUCHSIA might make more
> sense, but there is just too much drag and resistance
> on a larger animal.
Maybe we are talking about at least blackbird-sized ones, considering how
small *Microraptor* was and considering the quality of the fossil record...
> If flapping flight began
> underwater, I would imagine the entire body moving up
> and down with each wingbeat as a result of this
> resistance. If your body has less resistance than your
> enormous wings, then you aren't going to be moving
Should depend on the exact shape of the wingstroke... and the shape of the
body... at least such mechanical issues are testable.
> I've seen the gulls diving and flying down into
> "bait-balls" of sardines on TV as well. They appear to
> me to be having trouble doing so.
Gulls have very long, narrow wings, compared to Archie.
> > On the published photos, the hallux isn't longer
> > than Archie's, seems to originate at the same
> > height above the other toes as in Archie, and is
> > disarticulated from the metatarsus
> I can say that this characteristic is useful in
I can say it hasn't reached the threshold beyond which it would be useful in
climbing. -- Testable.
> What purpose would you invoke using the
> FUCHSIA model?
None at all. :-)
Only one species of gull, *Rissa tridactyla*, has lost the hallux, BTW; this
species walks very little, but breeds on rocks, so some perching ability
might be considered useful.
> The formula is simple: jump,
> fold wings, extend wings, angle wings up, raise wings,
> bring wings back to horizontal. How hard is that? Most
> of it would already be employed by conventional
It would descend in a stair-shaped path: parachute-glide-parachute-glide...
IMHO this is the most complicated method to get from A to B in a forest,
short of climbing down the tree and climbing up the other. I think it might
bring about the flight stroke to such an animal's distant descendants, but
no profit to itself. Does any living glider do this?
> Note that when the wings are brought back to
> horizontal that the animal would "hop" higher into the
> air, giving it a boost.
A weak origin for the downstroke... Is this testable? :-)
> > This is outside the realm of FUCHSIA. =8-) I think
> > arboreality came later, after flapping flight on
> > the level of *Confuciusornis* and/or *Sapeornis*
> > had evolved.
> So what should we expect to see in a bird "fresh out
> of the water" as far as adaptations go? Do *C.* and
> *S.* display them, or any other primitive birds
> excluding Archie? You said that the semiaquatic
> interlude was brief, so we shouldn't expect many
> changes at all.
Yep. We might actually expect nothing. I don't think the diving behavior of
a fossil dipper could be found out, unless at least the nostril flaps are
Oh, wait. A "bird fresh out of the water" should be able to fly. And indeed,
*C.* and *S.* could, and so could *Rahonavis*. :-)
> I hope your model is testable....
The biomechanical and hydrodynamic issues should be. For testing whether it
actually happened, rather than just being possible, we'll need a
tremendously improved fossil record, something like Messel or Sihetun, of MJ
or EJ age... and, see above, even that may not be conclusive.
> > > Birds simply flew out of the water, landed on a
> > > perch, and by a macromutation miracle modified
> > > this appendage?
> > Erm... yes, basically, but that took some Ma... :-)
> Right. But unless the hallux touched anything in the
> post-aquatic birds it wouldn't receive any
> evolutionary "stimulus" to change.
True. I have pretty little to say about that. I have yet to think up an
> > I think *Rahonavis*, with its very long wings and
> > legs, had specialized into
> > a secretary bird analogue that, unlike a secretary
> > bird, didn't need to kill its prey with its jaws.
Anyway, it must have been a pretty good flier, and must have evolved this
ability (as seen from e. g. the mobile scapula-coracoid joint) independently
of Ornithothoraces. Amazing convergence. -- When you ask me, Paraves should
be anchored on it. :-)