Re: A New Hypothesis for the Origin of Flight?

[Waylon Rowley <whte_rbt_obj@yahoo.com>]

Fam Jansma wrote:

> Pardon my sceptism, but wouldn't this just result in
> a big red spot on the Liaoning ground? 

Good reason to flap or evolve a hallux I'd say. 

> I do not mean to diss your hypothesis, not at all, >
it is based on some impressive facts, but this is 
> just plain suicide.
 
No worries, I'm not offended or anything. Pleased in
fact. Though I don't understand why branch-climbing is
suicidal among small theropods. 

> when you try to grap a branch or for instance,
> trying to get a ball out of the water, your friends
> hold you back in case you might fall.

Are you sure this is a good metaphor?

> See the friends as the elongated tail, but not 
> always it works this way, like I have
> experienced one time with a quick bath nature style.

So you're saying the tail might....detach? Or that it
might swing up and the creature would lose balance? If
you're refering to the latter, I would see that as
good reason to evolve larger terminal retrices or a
heavier tail. The arm feathers may have evolved as a
safety measure in case this took place (and obviously
it would), breaking the fall.  

> And second, not all supposed arboreal dinosaurs had
> extremely elongated tails, for instance, 
> Archaeopteryx does not have an elongated tail. 
> Should we conclude than that it was a ground-living
> bird?

If the scenario I originally proposed holds true over
time, it's likely that dinosaurs with shorter tails
represent better fliers, or descendants
of good fliers. The more flapping you did while
reaching for branches, the less need for a long tail
there would be. It's also possible the retrices of
Archaeopteryx helped make up the loss of mass. Notice
also that the distal caudals are more massive relative
to those in a normal dromie tail. For what purpose? 

> There is another example of a supposed arboreal 
> dinosaur who does not show the elongated tail, but >
I am not allowed to say much more...
> Bwahahahaha! >:)

But.....it does show other advanced climbing
adaptations that might make up for that. A very strong
hallux for one. The elongated 3rd manal digit would
also make a good wrap-around grasping organ, too
(assuming the 2nd was stiffened due to primary
feathers attached to it). If it is shown to have a
pygostyle, or interlocking caudals, the reduction in
tail length would be compensated for by feathers. It
needs a proper description before we can try to milk
any more info from our "sources"....heheheh.

   Just to clarify my view on how the arboreal dinos
climbed, lemme make a few comments so everyone knows
precisely what I'm talking about here.
   First, I don't see the animals hopping between
branches. I see them as having a firm foothold on
their *present* branch, while swinging or "jabbing"
their arms in the general direction of their *target*
branch. Basically using the momentum to heave both
them and their springy footing closer to the target.
The arms would latch on, and THEN they would hop over.
The jabbing or swinging motion could be very similar
to the flight-stroke, if not identical. Evolving a
lift surface on the wing would help get at higher
branches. Why would they do this? I'm guessing their
food source was further out on the branch....maybe
seeds or fruits, or insects or small vertebrates that
lived there. Or it was how they moved around the
forest canopy. Clearly you can't leap off a twig,
because it absorbs the energy, so you have to find
another way of moving - regardless of what was
portrayed in Crouching Tiger, Hidden Dragon.
Say...."Hidden Dragons" or a variation thereof would
make a good dino book title....

Cheers,
Waylon Rowley  

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