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Re: 11th specimen of Archaeopteryx



On 11/2/2011 2:27 AM, Scott Hartman wrote:
My explicit thesis is that Archie shows no adaptations at all for
climbing, and does exhibit adaptations for other activities.

That is not a thesis -- that is an observation.

As such
it's simply not responsible to continue to use Archie as the
inflection point for all of these hypothetical scenarios (or, if we
are to use Archie, to come up with scenarios that are reflected in its
anatomy).

Archie is well-suited physically to the minimal climbing needed -- as to all the rest, I am puzzled -- I thought we agreed that Arch + ancestors + etc were not birds...

As in --

Really?  Which birds that "only roost in trees" demonstrate the same
total lack of arboreal adaptations seen in the foot of Archaeopteryx?
Not just claw curvature, but phalangeal curvature, phalangeal
proportion, hallux position, and the utter lack of an enlarged flexor
tubercle of any kind on the claws.  And then add in "lack of flight"
and see where that puts Archaeopteryx.

Not a bird. That came later. You have the cart before the horse. As previously stated, I do not argue that Arch was a bird that roosted. I argue that being a feathered bipedal roosting cursorial animal is the only clear path to bird-hood, should the limited upstroke case be correct.

If you want to argue that Archaeopteryx simply
climbed up each night, then we should at least expect some sort of
climbing adaptations.

Why? How would putative climbing adaptations improve reproductive success in a roosting animal that forages on the ground?

As I said, there may simply be no need of potential energy.  Almost
all extant birds (Mike, correct me if I'm wrong, but perhaps Puffins
actually need some potential energy to take wing efficiently?) simply
don't make much use of it.

They were not birds, and had (assumed) limited upstroke. How is this relevant? They may have been able to fly some, but could glide. How would an animal w/ limited upstroke evolve passive gliding minus potential energy? Or do you exclude gliding as well?

Once you move past the ongoing (not just you) fixation
of trying to pin all of this on Archaeopteryx I think its a fine
working hypothesis.

As explicitly stated, ad nauseum, I am not trying to "pin all of this on Archaeopteryx".

Having fun already and haven't even gotten to Vegas?

Etc...