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RE: Wukongopterus and Darwinopterus





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> Date: Sun, 29 Nov 2009 16:12:48 -0600
> From: davidpeters@att.net
> To: david.marjanovic@gmx.at
> CC: dinosaur@usc.edu
> Subject: Re: Wukongopterus and Darwinopterus


>>> 2) short manual toes vs. short pedal toes on stegosaurs;
>>
>> Certainly correlated -- a single adaptation for quadrupedal graviportal 
>> locomotion.
>
> Correlated? Perhaps. But now let's nest stegosaurs in Dinosauria. Are they 
> still correlated? Doesn't this get to be a matter of opinion at one point or 
> another? 
 
 I thought Stegosaurs have been established to be bird-hipped dinosaur for at 
least five decades.  (or am I thinking of something else?)
 
 
>>
>>> 3) wide skull vs. orbits on skull roof on batrachomorphs;
>>
>> That term has fallen out of fashion.
 
 Pretty sure I saw it in _Gaining Ground_ by Dr Clack.
 
 
 
>>> 4) number of caudal vertebrae versus loss of teeth in birds, etc.
>>> etc. etc. The list is endless.
>>
>> So what? That it's time-consuming and difficult does _not_ mean we shouldn't 
>> even try. To the contrary -- if it were completely impossible, 
>> _phylogenetics would be completely impossible!!!_ Ignoring a problem never 
>> makes it go away.
>
> We're only trying to build a model here. So we don't wait until all the 
> animals that ever lived are available for their analysis, we jump right in 
> with a dozen to a dozen hundred taxa and build our model. We're not trying to 
> ignore a problem. As in calculus, we're trying to simplify it so it can be 
> understood.
 
  Isn't that how we ended up with "Pachyderma" with members like rhinos and 
elephants?
 
 
 
 
>>> Evolution abhors apomorphies, preferring parsimony.
>>
>> You're making this up.
>> You are making this up.
>>
>> "...and stop anthropomorphizing her, she hates that." There is no mechanism 
>> that informs a mutation that it has already happened elsewhere and therefore 
>> must not happen again. What did you think?!?
>
> By definition. Apomorphies are rare. By definition evolution is a slow 
> process with minor changes between generations. 
 
 So, should we break the bad news to the sirens (salamanders), the caecelians, 
the legless lizards, or the snakes?  Which group has to be moved to another 
nest?                                          
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