Deleporte on panbiogeography (+ O. furcatus)

John Grehan jrg13 at PSU.EDU
Tue Jul 2 22:21:16 CDT 2002

Ken Kinman wrote:
>Oh no,
>     That's what I was afraid of.  Minimal spanning tracks are another form
>of strict parsimony.  The longer these tracks are, the more I will distrust
>them.  Especially in the Pacific which was even wider in the past, while the
>Atlantic was narrower in the past.

Ken, it seems to me that you exemplify the traditional distrust of
biologists/systematists for geographic space. There are many philosophical
reasons one might invoke for disliking tracks, but it seems to me that such
objections are simply rhetorical devices if they avoid addressing the
empirical success of the method - such as predicting the composite tectonic
structure of the Americas before it was known to geologists.

>     I'm sure this works quite well in trans-Atlantic tracks linking South
>America to Africa or linking North America to Europe.  But the Pacific is a
>whole different ball game.

In what way?

>In that case, partial "Pacific rim"
>(amphi-Pacific?)  distributions are going to be more the rule, and
>trans-Pacific dispersals the rarer exceptions.

Please elaborate what you mean by this - with examples so I may respond.

>As we learn more about the
>mid-Cenozoic fossil record of Antarctica, I predict that new evidence will
>bear this out.

In what way?

>     The Pacific seems to have been a very effective barrier to long
>distance Oreobolus dispersal.

Since Oreobolus is distributed either side of the Pacific basin it seems
that the Pacific has not been a 'barrier' to Oreobolus dispersal (as
translation in space and form-making).

>It would not even surprise me if Oreobolus
>furcatus was somehow carried to Tahiti and Hawaii by humans (such as the
>early Polynesians), whether by accident or on purpose.

This seems to be just speculation. Is this all there is to biogeography?

>      Panbiogeography (at least as John has been explaining it) seems too
>restrictive and rigid, especially when applied to the Pacific.

Please explain

>Guess my
>eclecticism is showing once again.

In what way?

>But I just hate it when pendulums swing
>too far one way or the other, and biogeography seems to be no exception to
>controversy growing out of pendulum swinging (instead of seeking middle
>ground approaches).  Oh well.

Seeking the 'middle ground' seems to me to be just a rhetorical device that
has political rather than scientific significance.

I look forward to the elaborations if Ken wishes to do so.

John Grehan

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