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Re: Pneumaticity in Triassic pterosaurs



D Marjanovic wrote: 

>>Making a reasonably complete phylogenetic analysis of Archosauromorpha -- no, 
>>of the diapsid crown-group, because you say pterosaurs are lepidosauromorphs 
>>-- no, of Diapsida as a whole, because the contents of the crown-group are 
>>very uncertain; <<

There is no monophyletic Diapsida containing Archos and Lepidos. Did I not send 
you my tree? Your tree problem may be due to the assumption of monophyly in 
Diapsids.


>>not only do the euryapsids and the ichthyosaurs jump in and out all the time, 
>>so do others according to a couple of talks at last year's SVP meeting -- no, 
>>of _Amniota_ as a whole, because the turtles jump in and out of Diapsida, is 
>>not something you can whip together in an afternoon, or even in three months. 
>>It's enough work for a large chapter in a PhD thesis (...mine, to be exact).<<

Good luck on your thesis. I can show you the path of most parsimony if you're 
interested. The key to everything is taxon inclusion. You really have to sample 
from the whole gamut of the Amniota, plus quite a few outgroup sisters to get 
the picture. And it comes in very clearly. Thereafter, you can whittle down the 
tree to just 32 or so taxa to recover a similar basic topology. 

>>I've been telling you this for years now. The funny thing is, you never even 
>>voiced any explicit disagreement; you never wrote "you're wrong, it actually 
>>is easy"; you just shut up, and then a few weeks or months later you simply 
>>act again as if phylogenetics were like playing Minesweeper. <<

I don't get the emails from the DML daily. I check in every so often. If you 
don't copy me, as in this failed instance, I may not see your posting for some 
time later. I will always answer emails, however, as you know from experience. 
And I am always willing to help, including sending data, files, and images. And 
to that end, I am more than willing to accept new data that shows my data is in 
error. Hoping to hear from you soon, David. 

 BTW, M. Habib made a good point about hollow bones and apneumaticity. I'll be 
looking for those apertures next time I get out my 8x10 transparencies.

David Peters
davidpeters@att.net