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RE: Yet more on pterosaur quad arm posture



> Date: Thu, 4 Jul 2013 13:54:20 +1000
> From: tijawi@gmail.com
> To: dinosaur@usc.edu
> Subject: Re: Yet more on pterosaur quad arm posture
> 
> Gregory S. Paul <GSP1954@aol.com> wrote:
> 
>> In every single ground dwelling theropod we have the keration sheath for,
>> the toe claws II-IV are always flat. Same for all large land predators,
>> except those with retractile claws. The possiblity that large dromaeosaurs 
>> had
>> strongly arced toe claws is nearly zero (If they did it means that were
>> climbers, like big cats).
> 
> Circular reasoning.
If its even that. I remember using the comparison of big cats, and was reminded 
in no uncertain terms that the comparison was worse than useless because the 
tails, hips, and shoulders of the big cats and the dromaeosaurs are utterly 
different.

>> Because the ground is gritty and broad it will do much more foot feather
>> damage than less abrasive foliage that can be more easily avoided. Breeders 
>> of
>> feather footed pigeons and chickens don't let them wander about on dirt,
> 
> So if breeders didn't stop these ornamental birds from wandering about
> on the ground, they would go ahead and do it...?
One would certainly think so. 
> 
> 
> It's worth noting that we are not absolutely certain what the wings of
> small non-avialan theropods were actually used for. So we cannot
> assume that there was an adaptive penalty incurred by damaging the
> long feathers - such as inflicted by struggling prey; by snagging
> feathers on branches; by courtship/territorial battles; or by just
> walking around on terra firma.
To say nothing of the birds who lose most or all of their flight feathers when 
they molt.

>> Toe claws of ground animals are often worn down by the
>> grit, those of climbers keep sharp tips.
> 
> So do all theropods with extensive hindwings show _Microraptor_-like
> claw curvatures...?
This is a trick question, right?

>> Am disputing his posts just to make sure nonprofessional readers do not
>> swallow them without realizing they are controversial at best.
 Thanks for the consideration; but pretty much everything these days is 
controversial.