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

[David Marjanovic <david.marjanovic@gmx.at>]

> First, David, I saw the figure in the paper and do not catch what do you 
> say
> restricts femoral abduction in Microraptor. Not anything different from 
> what
> should impede abduction in the pigeon.

Well, it's just mechanically impossible given the femoral head and the 
acetabulum. The ilia are broken lengthwise to make the preserved position 
possible.

> Second, Jaime, you are right in that Cracraft 71' never said the femora 
> can
> splay out laterally in the horizontal plane. But they can rather abduct 
> much
> once they retracted so that the facies articularis antitrochanterica is no
> longer in contact with the antitrochanter. So, yes, you should not have
> completely-splayed out hindlimbs, but each hindlimb may have formed a, 
> say,
> 90° angle or somewhat more (not know of quantities) with the other in
> anterior view. Not the best for gliding but best than strictly 
> parasagittal
> limbs.

Fine, but pigeons have a distinct femoral neck and a somewhat rounded 
femoral head, right? *Microraptor* lacks all of that. (And so does 
*Archaeopteryx*.)

> Third, as far as I know, *Archaeopteryx* is more basal within the Avialae
> than *Microraptor* is within Deinonychosauria.

That doesn't mean anything except as a statement about the completeness of 
the fossil record.