Re: Paedomorphosis ( Re: BARYONYX' CLAWS )

["Matthew Troutman" <m_troutman@hotmail.com>]

<<May I suggest (with some trepidation as I have watched this argument 
develop) that a lot of this discussion is about semantics?  Who really 
cares whether what we are talking about is "flight", "swimming", 
"gliding", "controlled leaping" or whatever?  From an adaptive 
standpoint none of this matters. What does matter, I suggest, are 
questions like:

1.  To what extent are the forelimbs used in locomotion (in any medium)?
2.  To what forces are these limbs likely to be subjected during the 
course of this locomotion?
3.   What sort of structural adaptations exist to deal with these 
forces?
etc.>>

     I agree. Semantics has nothing to do with the argument. Whether 
penguins forelimbs are used like volant bird forelimbs is the issue. In 
penguins, plotopterids, and auks the forelimbs are used like their 
volant ancestors. This is what matters. 


<<Which brings me back to my other frequent point:  until we actually 
have good fossils of some of the early "protobirds" we are talking about 
any speculation on what these critters were doing seems idle, and in any 
case ignores the fact that they may have been doing all sorts of things 
using adaptations that either do not fossilize or are so slight in their 
differences from ancestral conditions that they might be exceedingly 
difficult to recognize, let alone interpret in any functional way.  
Thus, unless a fossil shows up that is both a clearly and considerably 
specialized volant or near-volant form and obviously
 represents an ancestor to both birds and at least some theropods, the 
"difference" between BCF and BADD may be minimal, unimportant or 
impossibl to distinguish.>>

These are very good points. 

MattTroutman

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