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RE: Campbell's even crazier than a MANIAC? (archeopteryx






> Date: Wed, 24 Sep 2008 23:39:27 -0500
> From: twilliams_alpha@hotmail.com
> Subject: RE: Campbell's even crazier than a MANIAC? (archeopteryx
> To: simkoning@msn.com; dinosaur@usc.edu
>
>
>
> Sim Koning wrote:
>
>
>> so I'm not to entirely sure what I was trying to get at LOL. Anyway, I think 
>> my point was that more
>> derived dromaeosaurids were probably descended from arboreal, flying 
>> animals, and may have
>> retained their ability to climb rather well, albeit not too habitually.
>
>
> Gregory Paul proposed this nearly 20 years ago - that derived dromaeosaurids 
> were descendents of small, arboreal flying theropods (like _Archaeopteryx_). 
> One day he may be shown to be right. These days, the idea isn't as 
> revolutionary as it once sounded (which is a credit to GSP).

I'm aware of this, I was basically just agreeing with what he proposed. I guess 
I should have cited him as a reference so I didn't come off like I thought I 
dreamed the idea up yesterday.





> But claiming that _Archaeopteryx_ or any non-avian theropod could "climb 
> rather well" is an overstatement, given their overall morphology ('bauplan') 
> and the proscribed ranges of motion at the joints (wrists, ankles, shoulders, 
> hips).

 This makes me want to ask this again; how much more mobile are the wrist and 
ankle joints of a hoatzin chick when compared with those of Archaeopterx? 
Hoatzin hatchlings seem to be pretty good at climbing to me.





>> For example, lions are not very good at climbing trees, but they still 
>> retain this ability that was inherited
>> from their smaller ancestors.
>
>
> I didn't know this. Which "smaller ancestors" do you mean?

Good point, tigers are pretty damn good climbers, and they are actually larger. 
Not really sure what I was thinking there.


>> As far as what Archaeopteryx were climbing; the fact that they had greatly 
>> elongated hooked fingers
>> seem indicative to me that they climbed through bushes and trees not unlike 
>> a Hoatzin chick.
>
>
> Long fingers tipped with curved claws are standard issue for maniraptoran 
> theropods. Deinonychosaurs used them in predation, and there's no reason why 
> they didn't perform the same function in _Archaeopteryx_. The hands of 
> _Archaeopteryx_ might have been used for both climbing and predation. If they 
> were used for climbing, the hands could maybe have been used for grappling 
> branches, or grasping trunks with both hands.

Yes I agree, but most predatory theropods had much shorter fingers. 
Deinoniychus had very long fingers, but this animal may have decended from 
forms similar to Archaeopteryx. Therizinosaurs had greatly elongated claws, but 
these may have been used to grasp branches. To me the long, thin fingers of 
Archaeopteryx look more like the toes of tree climbing lizards than the massive 
grasping claws of other predatory dinosaurs.









>
> Cheers
>
> Tim


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