RE: Thoughts on the biggest morphological bird analysis

[Tim Williams <twilliams_alpha@hotmail.com>]

Mickey Mortimer wrote:

> Furthermore, comparison with mammalian phylogenies suggest that convergent 
> taxa group together in morphological analyses, sometimes with large support 
> indices.  In Asher et al. (2003), two of the best supported clades are bats 
> plus flying lemurs, and pangolins plus anteaters.  Much as I'll continue to 
> support these groups being convergent, I'll support grebes and loons being 
> convergent too.

I take a very different view.  I don't think it's quite correct to assume 
that when a morphology-based analysis disagrees with a molecule-based 
analysis that the former is at fault.  Both kinds of analyses (morphological 
vs molecular) have problems with homoplasy.  However, when
homoplasy is thought to be the culprit in morphological analyses it's often 
easy to identify the potential source - such as the grebe-loon example, 
where you claim that adaptations in foot-propelled diving are pulling grebes 
and loons together.  With molecular analyses the source is less tangible, 
because you're working with bases or amino acid residues, not morphological 
characters.

I have no problem with a grebe-loon clade, nor a bat-colugo clade - despite 
what the molecules seem to say.

Cheers

Tim

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