[Taxacom] Drosophila melanogaster name change?

Kim van der Linde kim at kimvdlinde.com
Tue Apr 13 14:32:19 CDT 2010


Richard,

On 4/13/2010 12:17 PM, Richard Zander wrote:
> I read way too much agreement (about paraphyly, survival of ancestors
> after speciation, robust taxa, phylogenetics not being the end-all) in
> what you say.

I am sorry if I made you uncomfortable, I will see if I can find some 
disagreement with you.....

> Are you a member of the Post-Phylogenetic Systematics
> Society? Have you been taught the secret hand-shake? Have you paid your
> (nominal) dues?

LOL, maybe we have to start one. No, I had a decent taxonomic training 
when I did my masters (just imagine how hard I had to laugh when someone 
tried to kick my legs from under me by telling me that I should take a 
decent course in taxonomics), but it is my nature not to adhere to the 
mainstream ideas (if I had done that, I would not have proposed to split 
the genus in the first place) but think for myself.

During my Masters, we had a semester long colloquium just on species 
concepts and how you could determine when something was a species. That 
was when cladistics was still done with a software package called Hennig 
##. Together, it taught me is that each of the various species concepts 
have their value, each in their proper context. I think the phylogenetic 
species concept is much more valuable for phylocode than for rank based 
taxonomy.

The same problem that you have with phylogenetics, I have with 
traditional morphology based cladistics. It is very easy to rake up a 
lot of traits, run an analysis and find a single trait that is dividing 
the species in two nice groups. Whether or not that trait is 
evolutionary relevant, that is often ignored. And that is in part the 
problem with Drosophila.

The good thing in Drosophila is that the phylogenetic work actually has 
a reasonable similarity with the evolutionary work that has been carried 
out over the past decades.

What we have now with Drosophila is the remnant of 18 decades of fussing 
around with the genus. We can easily spend another decade or 5 to figure 
out all the details for each and every species in the genus and the 
included genera before taking any action. I am convinced that the 
outcome is not going to be substantially different, other than that we 
can fill in many more details about obscure and rarely investigated 
species. The upcoming proposal to split the genus is in many ways a very 
modest proposal (4 main (250+ species), some smaller (1-10 species) 
clades). I think a much more comprehensive revision, with some more risk 
of making the wrong decisions would split the genus in 7 major clades 
(50+ species) and a lot of smaller clades (1-50 species). The main thing 
this revision will do is to eliminate the Sophophora melanogaster 
problem, which I think is a good thing.

> I largely disagree that different genetics make different taxa. I think
> that different evolutionary directions are, yes, mediated by genetics,
> but different genetics do not necessarily, or even usually, imply
> speciation processes. We need more information about evolution than the
> genetic element.

Agreed, although I am personally okay with deciding that two clades are 
different species if the genetic difference is large enough not in 
absolute terms, but comparatively with regard to the variation within 
the two clades.

Regards,

Kim




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