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Re: What are the biggest highlights of modern paleontology?



David Marjanovic <david.marjanovic@gmx.at> wrote:

>> Well, the Eunotosaurus  "comeback" is highly questionable to some (if
>> you mean as a turtle ancestor).
>
> I know all molecular phylogenies continue to be against it (though the
> latest study I've seen is surprisingly inconclusive on this topic* and on
> Lissamphibia). But has the anatomy of *Eunotosaurus* been questioned? The
> trunk ribs are pointed (indicating loss of the sternum), have the same
> number as in turtles, and are fused to plates of dermal bone that immobilize
> the trunk... and on the other side, there's still no trace of a cleithrum in
> any crown-group diapsid.


If _Eunotosaurus_ is *not* on the line leading to turtles
(Testudinata), then it's a truly remarkable case of convergence.
_Eunotosaurus_ has exactly those characters that we would expect to
see in a stem-turtle.  But that alone does not make it a stem-turtle.


It's a bit like _Hupehsuchus_ and ichthyosaurs.  Is the former a basal
ichthyosaur... or does it just happen to look like a basal
ichthyosaur?







Cheers

Tim