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Re: Livezey and Zusi's big bird morph analysis [...]



> As for the proposed grebe-loon clade, L & Z point
> out that this clade does 
> not include *all* foot-propelled diving birds, like
> hesperornithids for 
> example.  So it's not just a case of convergence
> being mistaken for a 'real' 
> (synapomorphic) relationship.

But the case for convergence confounding analyses has
been made, time and again, for exactly this clade. It
is THE showcase example where parsimony is likely to
run into a wall*, and has been since more than a
decade (in fact, try doi:10.1007/BF01908745). This
cannot be dismissed out of hand. Basically they
reiterate a cold case; this is not good.

Eike


* Especially in such large-scale analyses, where the
data set cannot be sufficiently fine-grained because
it could then not be applied to many other taxa. A
morphological analysis of foot-propelled divers that
is good (IMHO) would run into problems as soon as it
comes to outgroup selection, because the character set
would include a load of F-PD apomorphies.


                
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