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Re: Sci. Am. - present. [long]



> As an Amateurid (hopefully Gottaclueidae), this timing issue 
> is the one thing that bothers me about the birds from dinosaurs 
> hypothesis. However, this type of response from the BFD camp 
> bothers me even more. It reminds me of arguments by the Aquadic 
> Ape enthusiasts on sci.archology, "We must be right because 
> there are no fossils to prove us wrong." Why not just admit that 
> this is a problem and that you are working to resolve it?

     I challange anyone who sees the absence of Jurassic dromeosaur
and troodontid fossils as a huge problem for the idea that dinosars are
not ancestral to birds to show me the Jurassic fossil that IS.  You can't,
because it hasn't been found either.  Unless _Archaeopteryx_ popped out of
nowehere, it is safe to say that the fossils of bird predescessors haven't
been found, period, whatever they may have been. Dromeosaurs and
troodontids are known from the early-mid Cretaceous, but
we haven't found the transitional forms between then and thier earlier
non-dromeosaur and non-troodontid ancestors either; but I think its safe
top say that they existed.  The Jurassic is an almost blank slate for a
lot of animals that pop up in the Late Jurassic and Cretaceous, and to say
the very least, dromeosaurs and troodontids are no more unlikely to be
present in the Jurassic then any other established group that apparantly
pops out of nowhere in the Cretaceous.
     The prospect gets more likely if you look at the anatomical evidence
tying dromeosaurs and troodontids to birds. Your aquatic ape analogy
applies more to advocates of ALTERNATIVES to "BFD"; the dinosaur-bird link
doesn't NEED to invent a completely unknown intermediates, just slightly
extend the temporal range of a very well documented one.  Look at the
other candidates without more then VERY superficial resemblances linking
them to birds; _Megalanocosaurus_, _Longisquama_, or hypothetical flying
crocodylomorphs, and it becomes pretty clear which current idea on bird
origins is the most plausible.             
 
LN Jeff