[Taxacom] Hypothesis: How Nothofagus rafted to New Zealand

[Ken Kinman]

John Grehan wrote:
    >Ken's basic methodology seems to be imagining that vicariance is
>falsified, then imagining dispersal is the only probable alternative.  No 
>wonder historical geologists don't take biogeography seriously.
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John,
    Actually that is just the first step in my methodology.  Brainstorming 
all the different possible scenarios, and then seeing whether lines of 
evidence from other organisms fits any of those scenarios better.  If lots 
of organisms show similar patterns supporting a dispersal scenario and
they contradict a vicariance scenario, then I would say my intuition was 
correct.

     If those lines of evidence fit a vicariance scenario, then I'll cry 
"uncle" and congratulate John Grehan on his insight.  Vicariance almost 
certainly played a major role in the evolution of the Nothofagus faunas of 
South America, Antarctica, and Australia, but the relatively early 
separation of New Zealand makes me strongly suspect Cenozoic dispersal from 
Tasmania for Nothofagus and its parasites.  We shall see.  The brainstorming 
part is over, and now the more difficult task of gathering various lines of 
evidence, both morphological and molecular (and seeing if they contradict or 
support vicariance).
    ------Cheers,
              Ken Kinman
P.S.  I am still in the brainstorming stage on the question of the northern 
Nothofagus group (New Guinea, etc.).  It has been suggested that lack of 
Cyttaria might indicate it split off first from other Nothofagus groups, in 
contrast to other evidence indicating it was more phylogenetically derived.  
I think I'll keep my "imaginings" on that subject to myself for now (as I am 
sure some people probably think this thread has already gone on too long).  
:-)

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