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Re: Re: early birds, etc.



>
>>From Thomas_R_HOLTZ@umail.umd.edu Tue Mar 29 09:52:47 1>
> > This is probably true for Sinornis' lineage.  However, almost all
> other
> > Mesozoic birds (Icthyornis, Hesperornis, Patagopteryx, the
> > Enatornithoformes, etc.) are demonstrably nonarboreal.
>
>These are all very specialized forms, anatomically speaking,
>so they are hardly likely to be characteristic of the earliest
>birds.
>
>[The fossil record of birds is deomnstrably worse than of any
>other boney organism, excpet perhaps small theropods].
>
> > Thus, Sinornis shows
> > that birds were capable of evolving arboreal forms, but is
> phylogenetically
> > distant from the common ancestor of modern perchers/tree dwellers.
>
>Probably, but so were the aquatic forms you listed!
>

Actually, all these aquatic forms, and particularly the icthyornithoformes
and hesperornithoformes have been shown to share a more recent common origin
with modern birds than with Sinornis, even though Sinornis does have the
general "gestalt" of modern perchers.

>swf@elsegundoca.ncr.com                sarima@netcom.com
>
>The peace of God be with you.
>
>

Thomas R. HOLTZ
Vertebrate Paleontologist, Dept. of Geology
Email:Thomas_R_HOLTZ@umail.umd.edu (th81)
Phone:301-405-4084