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Re: Campbell's even crazier than a MANIAC? (archeopteryx climbing)



I'm sure this has been raised before many times, but how does does the morphology of the Hoatzin compare with that of of Achaeopetryx, or for that matter to other to other birds. Stated another way, are there any unique osteological features for bush climbing in hoatzins that might be useful in inferring behavior in archie and dromaeosaurs? I suspect not, which is, of course, the root problem of the debate. This is beginning to look like the movie Ground Hog Day. Then again maybe less is known about the functional morphology, osteology, and biology of the hoatzin than one would expect.

Dan

dinoboygraphics@aol.com wrote:
"Good point, but do any climbing vertebrates actually stick their claws well into the bark in the manner of crampons in ice? Couldn't they simply use the pedal claws to grasp the bark? "

That of course is probably a better question, but takes us right back to wrist and ankle morphology. I am unaware of any analogous trunk climbers that lack highly mobile ankles and wrists (and femora, for that matter). These guys all sprawl and twist their hands and feet around to get up the substrate, which Archaeopteryx (and other manirap...heck: theropods) could not do.

I'm not saying Archaeopteryx could never, ever get into a tree. If an archie found a tree (no easy chore in its particular environment) and was highly motivated (perhaps a competition?) I'm sure they could manage to scamper up some form of tree. I'm just pointing out that they lack specializations for the activity, and exhibit several that hinder climbing, so the inferred importance of arboreal behavior should be kept to a minimum at the level of Archaeopteryx.


Scott Hartman Science Director Wyoming Dinosaur Center 110 Carter Ranch Rd. Thermopolis, WY 82443 (800) 455-3466 ext. 230 Cell: (307) 921-8333

www.skeletaldrawing.com


-----Original Message----- From: Dan Chure <danchure@easilink.com> To: dinoboygraphics@aol.com Cc: dinosaur@usc.edu Sent: Wed, 10 Sep 2008 9:45 am Subject: Re: Campbell's even crazier than a MANIAC? (archeopteryx cli mbing)


Good point, but do any climbing vertebrates actually stick their claws well into the bark in the manner of crampons in ice? Couldn't they simply use the pedal claws to grasp the bark? Dan dinoboygraphics@aol.com wrote:
Sorry, I just got to this point in the discussion:
Crampons have points directed in two directions. A set of 8 or so
> are on the bottom of the crampon for walking on icy / snowy surfaces. > Two point forward from the front, to gain purchase on high angle or > vertical surfaces, with the foot simply projecting into space. One can > even stand with a single front directed point in the ice, is it is set > well enough in the ice. But is such cases one is using ice axes or > some such with one's arms.<<<
Um, crampon spikes are all essentially straight along the blade, for
a > very important reason: so you can get them out again! Unless the > second pedal claw was particularly straight, it would be near > impossible to pull out of the substrate, especially if you've moved > yourself up relative to the original point of insertation. With manus > claws this is less of an issue, since the axis of rotation is usually > set below the point of entry even after pulling yourself up, but the > toes have no such advantage, especially in non-splayed stiff-limbed > maniraptorans. Trying to make Archie a
n adapted climber is an act in > trying to make the facts fit a theoretical preconception on how flight
should begin (if it even began in an Archaeopteryx-grade paravian).
My advice is to stick with skateboarding. <<<
They'd have to, as climbing vertical trunks would be right out. Scott Hartman Science Director Wyoming Dinosaur Center 110 Carter Ranch Rd. Thermopolis, WY 82443 (800) 455-3466 ext. 230 Cell: (307) 921-8333 www.skeletaldrawing.com -----Original Message----- From: Dan Chure <danchure@easilink.com> To: david.marjanovic@gmx.at Cc: DML <dinosaur@usc.edu> Sent: Sun, 7 Sep 2008 6:20 pm Subject: Re: Campbell's even crazier than a MANIAC? (archeopteryx >
climbing)
I'm not sure what you mean by side-to-side. Crampons have points >
directed in two directions. A set of 8 or so are on the bottom of the > crampon for walking on icy / snowy surfaces. Two point forward from > the front, to gain purchase on high angle or vertical surfaces, with > the foot simply projecting into space. One can even stand with a > single front directed point in the ice, is it is set well enough in > the ice. But is such cases one is using ice axes or some such with > one's arms. My advice is to stick with20skateboarding. > > Dan > > David Marjanovic wrote: >>> Setting aside true arboreality for the moment - how well would they > >> be have been able to use their claws as crampons for ascending >> > trunks, rocks, whatever? >> >> Don't crampons work side-to-side? Sickle claws worked top-down and > > probably had a cutting edge. They were not round in cross-section. >>

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