Re: PTEROSAURS: AVIAN ANCESTORS?

[Betty Cunningham <bettyc@flyinggoat.com>]

weren't pterosaurs (similar forms to Pteranodon) descended from
rhemphorynchinoids (little guys with teeth and long tails)?  So
pterosaur shoulders are descended from very small ancestors who did NOT
have enormous wings (yes - no ?)  

What kinda shoulder girdle did rhemphorynchinoids have?  How similar are
they to the later pterosaurs?
If the smaller earlier forms have the same shoulder details as the later
more powerful forms, it won't fit your theory. They would not have
evolved to handle heavier musculature if they evolved FIRST, BEFORE the
heavy musculature.

-Betty Cunningham

Larry Febo wrote:
> I`m not sure if these details aren`t related to the more powerful
> musculature needed by these pterosaurs to move their enormous wings without
> collapsing the ribcage. These might be  the features expected in a more
> advanced, and hence specialized form, not the more primitive, generalized
> form that birds might have evolved directly from. Even Wellnhofer states how
> even the earliest pterosaurs recorded seem already specialized to their
> particular mode of flight , and a great gap existing in the fossil record as
> to what exactly led up to the first pterosaurs,(as we know them). I guess
> what I`m looking for  as a common link between aves, and pterosaurs is as
> yet a hypothetical form. Still, I would think that what can be observed of
> the similarities between the two forms, even in their advanced, specialized
> states might suggest the existance of such a hypothetical ancestor. I know
> that "hypothetical" arguments tend to be weak, and subject to flaw, but ,
> again, in these areas of scant fossil evidence, what recourse is there? I
> guess this will remain as another of my "hunches" until some solid fossil
> evidence shows up to prove, or disprove my hypothesis. Thanks for the
> "debate", it has given me much more to think over. And, I don`t want to get
> into the "maniraptoran ancestry of birds," or vice versa, as I`m sure that`s
> already been debated to the hilt!