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Re: Re: Flightly PaleoWorld



>The show did not mention any common ancestral forms for Archy
>and dromaeosaurids, for example, nor did they mention small size as a
>necessary pre-adaptation for flight.
and
>The overall impression I was left with was that we had these 50-100 kg
>Deinonychus-size dinosaurs climbing into trees as the first stage in the
>development of flight. Balderdash.

You are dead on target here.  They certainly portrayed the BAAM (Birds Are
Advanced Maniraptorans, just can't bring myself to use BADD... :-) ) in the
worse possible light: i.e., that large dromaeosaurids were directly
ancestral to birds. No one has advocated this position, since raptors occur
to late and are too derived to be directly ancestral to birds.  Sister
group, yes; ancestor, no.

>Longisquama is a good example of a small Triassic protobird, although it is
>too derived to serve as a theropod/avian ancestor. I can't imagine that it
>appeared by special creation in the fossil record of Russia, so there must
>have been related/ancestral species, very probably dozens, probably even
>hundreds, alive during the Triassic all over Pangaea. Why is this so hard to
>believe?

It's not that it is hard to believe, it's just that fossil evidence for them
in great quantities in the Triassic are lacking.  A globally distributed
Longisquama is certainly a strong possibility, but a highly diverse
assemblage of such critters will need more fossils for support.

(Then again, since the Middle and Late Triassic are the peak of bizarre
reptilian experimentation, it wouldn't be especially surprising).

Thomas R. Holtz, Jr.
Vertebrate Paleontologist
Dept. of Geology
University of Maryland
College Park, MD  20742
Email:Thomas_R_HOLTZ@umail.umd.edu (th81)
Fax: 301-314-9661
Phone:301-405-4084