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Pterosaur pelves, pterosaur origins



Pterosaur pelves, pterosaur origins.

In fact the appearance of elongate ilia (specifically the anterior iliac 
process) 
takes place inside the clade Pterosauria. Really basal forms such as 
Dimorphodon 
actually have relatively short ilia with anterior and posterior processes that 
are of similar length and quite slender in their construction. Sharovipteryx, 
by 
contrast, has a relatively elongate anterior iliac process which is more like 
that seen in derived pterosaurs. And, while I am on the subject of problems 
with 
the 'pterosaurs are most closely related to some prolacertiforms' hypothesis I 
should mention that I have seen a paper reanalysing Peters work that, as I 
understand it, is now in review and, assuming that it is accepted and appears 
later this year, that thereafter it will not be entirely correct to claim that 
Peters hypothesis is the best available. 

In the meantime, in my opinion, the only really sensible thing that can be said 
of pterosaurs relationships to other diapsids is that there are at least three 
different hypotheses, each have data that supports and contradicts them and not 
one of them is so overwhelmingly supported or accepted that it can be said to 
have become the favoured hypothesis. Again, a lot more work is needed if we are 
to make any progress toward solving this problem.  

Piff, poff, paff, as we say in my house,

Dave