Panbiogeography of the Americas

[Stuart G. Poss]

John Grehan wrote:

Page (1987) for one gave some detailed attention to the proceedures.

I probably should be familar with this work but I do not recall reading it.  Can
you provide a complete citation?  Are these widely agreed upon among
panbiogeographers as the appropriate methods of choice for establishing track
geometries?

> >There has been much discussion of tracks, but these always seem to be described
> >as some relatively vague association between two or more non-contiguous
> >distributions of presumtive sister-taxa.
>
> What paper are being refered to that substantiates this characterization?

 I'm just trying to understand the operational and logical basis of this approach,
if any, so the characterization is purely my own observations regarding what I have
read so far.

> This is where the development of statistical techniques is desirable. Craw
> has applied
> compatibility analysis to answer this kind of question.
>

Interesting, despite the fact that compatibility analysis is not in an of itself a
statistical technique, although Meacham has developed a solid mathematical
foundation for one reasonable model of randomness.   Unfortunately geographic
location can not be coded like taxonomic features, since an organism can have
different codings simply by moving from one place to another.  Nor is it clear what
"states" one should use to code for geographic "characters".  Are all states "not
present at locality X" the same?  Its not really appropriate to talk about
recognizing "patterns" until such distinctions have been clearly made.

Can you provide a complete citation?  Are the referenced algorithm(s) freely
available?

> >There was a paper discussing the inability of track analysis to address last
> >issue, I believe by Simberloff and colleagues, but I can't remember the exact
> >citation.
>
> Simberloff just pointed out the absence of statistical tests for track
> analysis. At
> the time there were none. Now there are.

This is Craw's work?  Or are there other citations within which mathematical
analogies are used to give precise meaning to the ideas presented?

>  Please give a specific map example and I will comment.

Take a look at Rosen's work in Systematic Zoology on the origin of the Antillean
fish fauna for one.

> Minimum distance, main massings.

If this is the case, ocean currents will largely confound the usefulness of this
technique for marine biogeography..  Because of the Coriolis force and because
continental margins create obstacles around which fluids and the organisms in them
must flow, they seldom travel in straigh lines of minimum distance.   Likewise
non-linear coastal margins will confound the approach when dealing with coastal
species.  Perhaps this was a problem with Rosen's analysis.  He used the
"approximate convex hull" technique for defining tracks as opposed to the "minimum
distance approach."

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_____________________________________________________________________
Stuart G. Poss                       E-mail: Stuart.Poss at usm.edu
Senior Research Scientist & Curator  Tel: (228)872-4238
Gulf Coast Research Laboratory       FAX: (228)872-4204
P.O. Box 7000
Ocean Springs, MS  39566-7000