Centre of origin digression

[Karl Magnacca]

On 2 Apr 2005 at 21:48, Robert Mesibov wrote:
> Do you _define_ your taxa with the help of geography? Or do you define them
> with inherent characters alone?

Are you suggesting the former is preferable?  That sounds like a quick
path down a slippery slope.  To give an example, in a book on the
crickets of Hawaii, a population from the island of Molokai was
separated specifically from identical ones on Maui because "all species
in this genus are island endemics".  This was then repeated three times
consecutively.

> Does the geographical information in your keys tell people anything
> more than where your character-based taxa can be found?

Not mine, except that it makes them easier to separate than the minute
characters that actually do differentiate them.  What do you think it
should be telling people?  Without a phylogeny and inference of
ancestral distribution I don't see that it tells you anything else.

> I'm just sad (all right, grumpy) that so many systematists do so little
> biogeography in parallel with character-based analysis.

I won't disagree with you there.  I think a lot more information could
be gained with relatively little extra work by throwing in biogeographic
analyses (at least for places; times are another matter).  On the other
hand, the fact that so many phylogenies are based on relatively thin
sampling makes doing biogeography from them more sketchy.

Karl
=====================
Karl Magnacca, USGS-BRD
PO Box 11, Hawaii Natl. Park, HI 96718
"Democracy used to be a good thing, but now it has
gotten into the wrong hands."   --Sen. Jesse Helms