Re: PTEROSAURS: AVIAN ANCESTORS?

["James R. Cunningham" <jrccea@bellsouth.net>]

Matthew Troutman wrote:

> Early pterosaurs also have a unique coracoidal articulation to the
> sternum; the coracoids are articulated one behind the other.

Quetzalcoatlus maintained the stepped coracoid articulation right up to the
end of the Cretaceous.

> 2)  This scenario assumes that bird ancestors had a large amount of
> aerodynamic control because hind leg first landings are hard to
> accomplish.

Matt, I'm not sure I followed what you're saying here.  To me it seems that
hind leg first landings would be easier to accomplish.  Is that your point
as well?

> Pterosaur wrists seem to been rather specilized.  The elements do not
> seem to be analogs to the cuneiform, scapholunar, and semilunates of
> bird wrists.  _Archaeopteryx_ has four carpal elements.  Pterosaurs have
> two or three.

The pterosaur wrist casts I have here show no geometric similarity whatever
to bird wrists.  They allow a similar motion, but do so with a very
different structure.

> So, in conclusion, it seems that pterosaurs and birds share no real
> similiarities other than classic flight features.

I agree.JimC
P.S. Are you going to be at Snowbird?  I look forward to seeing you there

> Matt Troutman