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Re: Reporting back again!
>At 07:59 PM 10/11/98 +0000, Luis Rey wrote:
>later tried to sell us a
>>'flying' Megalancosaurus as a 'possible' bird ancestor. Sorry... didn't buy
>To be fair to Ruben, he *explicitly* stated that he did not consider
>_Megalancosaurus_ a bird ancestor of any sort. However, he did say that we
>shouldn't dismiss information from it (specifically, his interpretation of
>it as a glider) as a model for some hypothetical stage in avian origins
>(following the Bock scenario-driven hypothesis of bird flight origins).
>Thomas R. Holtz, Jr.
I think if we read the message of the talk as a whole (despite a lot of
rethoric babble to cover his back, creating an appearance of being open,
amiable and conciliatory) he was trying desperately to cling to something.
His description of Megalancosaurus included a lot of dubious protoavian
characteristics (and he didn't mention that it is regarded as a
prolacertilian, had a prehensile tail not a rudder, and that the four hand
fingers were paired and opposable as in a chameleon.)
If he really wanted to hypothesize a 'trees down' alternative he could have
done better if he endorsed George Olshevsky's BCF theory. George used to
regard Megalancosaurus as a model for a distant 'possible' ancestor... but
then we return to what Ruben doesn't want to see: Pterosaurs and Dinosaurs
would form a natural family. ALL dinosaurs would have been arboreal and
keep descending from the trees in different stages of evolution 'towards'
the ultimate bird design. That is, all dinosaurs would be birds and birds
The fact that is that his talk >still< included a reiterative appraisal of
Sinosauropteryx protofeathers as collagen fibers (which will be
demonstrated,if not it's already, as one of the greatest fairytales of the
XX Century). So I didn't see a critical and thoughtful reappraisal... just
politics as usual.
I contend that protofeathers, feathers and warmbloodedness are basal
characteristics of the Dinosauria (which Lagosuchus-like thecodontians were
incipiently developing and gave way to the also warmblooded Pterosaurs)...
and I think this will continually be proven so.
Visit my website on http://www.ndirect.co.uk/~luisrey