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RE: Campbell's even crazier than a MANIAC? (archeopteryx climbing)
Well, while I am unconvinced archie dwelt in trees, its worth noting that goats
climb trees quite well, but their morphology (particularly having hooves) does
not immediately suggest this, and parhaps the focus on the foot is over rated.
I wouldn't say they couldn't have regularly went in trees. I still think its
more likely any flying they did was along a coastal bluff with a seabreeze, and
its still possible they used their forlimbs for something other than wings.
Goats in trees:
--- On Tue, 9/16/08, Tim Williams <email@example.com> wrote:
> From: Tim Williams <firstname.lastname@example.org>
> Subject: RE: Campbell's even crazier than a MANIAC? (archeopteryx climbing)
> To: email@example.com, firstname.lastname@example.org, email@example.com
> Date: Tuesday, September 16, 2008, 5:10 PM
> Augusto Haro wrote:
> > It is true that primates can grasp, but what I said is
> that they do not
> > have such a retroverted pollex as in birds, yet they
> can grasp the same. If
> > the digits are sufficiently splayed out, they can
> grasp more firmly, even if
> > not having a completely retroverted pollex.
> > I do not think that the lack of perching foot is to be
> strange in a glider.
> > as far as I know, there are no retroverted digits in
> either colugos, *Draco*,
> > or gliding squirrels. Indeed, grasping foots are most
> developed in slow
> > climbers, such as chameleons, or lorisids. Arboricole
> iguanas do not present
> > perching feet yet they are faster moving than
> Yes... but all these critters have (by and large) a
> quadrupedal gait, flexible wrist and ankle joints, and a
> supple spine. In short, they're fairly well adapted to
> life in the trees (or at least climbing). Gliding
> squirrels, for example, use gliding to commute from tree to
> tree and so bypass the ground. So, the comparison between
> any of these animals and _Archaeopteryx_ breaks down very
> quickly. _Archaeopteryx_ was a biped with a fairly rigid
> backbone, and wrist and ankle joints with proscribed ranges
> of motion.
> Perching is a way of reconciling obligate bipedalism with
> arboreality. Theropods (as dinosaurs) are primitively
> bipedal. So if birds had descended from arboreal animals
> (like a 'tetrapteryx'), or had become arboreal early
> in their history, one might expect to see specialized
> perching adaptations in the most primitive birds, like
> _Archaeopteryx_. Yet we don't.
> > Yikes, that paper you pointed to seems to get the
> arboreal-claw-argument to
> > trash (will try to download). Serious blow to the
> arboricole theory (and I
> > think perhaps its better support), but thank you.
> You're welcome. The "tree-dwelling
> _Archaeopteryx_" idea has never had much support from
> anatomical evidence. Sure, _Archaeopteryx_ might have
> ventured up trees; but it certainly wasn't very well
> adapted to this kind of behavior. Glen and Bennett's
> study reinforces the hypothesis that _Archaeopteryx_ divided
> its time between the ground and the trees. There's
> other studies that support this idea (e.g., Hopson's
> paper in the Ostrom symposium volume.)
> > You can climb without using the forearms, for example,
> using WAIR.
> But can WAIR get you all the way up a vertical trunk?
> >From another thread...
> Eric Boehm wrote:
> > So my related question is: Is there a fundamental
> superiority to Mammalian quadruped predators that
> > resulted in them outcompeting the Biped "terror
> birds" (really the closest thing after the KT to a
> > dinosaur), or was it an accident of geographhy?
> Maybe the success of predatory mammals vs predatory birds
> has more to do with teeth, rather than bipedality vs
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