[Taxacom] Nothofagus flying to NZ

[Ken Kinman]

John Grehan wrote:
     >Evidence relating N gunnii tow New Zealand species has nothing to do 
with how they got to be where they are now.
--------------------------------
John,
    How can you possibly believe that such evidence has NOTHING to do with 
it?  It certainly isn't the whole story, but how can you say "nothing".  It 
may actually have more to do with it than the timing (which seems to be your 
main "beef" with those molecular papers).  The timing issue is very 
difficult to document, so it is the easiest target to pick on, and you seem 
intent on ignoring anything which contradicts your belief that Nothofagus 
couldn't possibly disperse over the Tasman Sea and it just HAS to be due to 
vicariance.  So let's look at the evidence that isn't dependent on the 
timing issue or controversial pollen data.

     It's not just N. gunnii being closely related to the Fuscospora species 
in New Zealand---also, in subgenus Lophozonia, the close relationship of 
Tasmania's N. cunninghamii and New Zealand's N. menziesii has a "track" that 
is virtually identical.  Furthermore, it's not just molecular data, because 
morphological evidence show the same "track"---namely Tasmania's fossil N. 
cethanica also being closely related to New Zealand's Fuscospora group (too 
bad we don't have molecular sequences for N. cethanica to add to the 
evidence).  Not to mention that this "track" takes us to the nearest 
significant landmasses to New Zealand----namely, Tasmania and adjacent 
Australia.  These are independent, but congruent, lines of evidence 
(molecules, morphology, AND biogeography) supporting dispersal across the 
Tasman Sea.

    I will discuss even MORE evidence (Cyttaria fungi unique to Tasmania's 
Nothofagus cunninghamii and New Zealand's N. menziesii) in my next posting 
(entitled Hypothesis...).  Meanwhile, I have a few more bones to pick with 
panbiogeographers.  I thought you actually liked having short straight 
"tracks" like the one I am drawing from Tasmania to New Zealand, but I guess 
insisting that it MUST be vicariance is just too irrestible.  Vicariance 
actually is often the answer, but let's not get carried away.  Let us have a 
few dispersal tracks as well.

     Now I would like to rant a bit about "main massings".  I do not 
understand Heads insistence that subgenus Fuscospora has its "main massing" 
in New Zealand.  Are we supposed to be impressed that it radiated into three 
species in New Zealand (and the molecular data indicate they radiated very 
recently, so maybe there are only two anyway).  In any case, the mostly 
likely place for the real "main massing" AND origins of Fuscospora (and 
perhaps some of the other subgenera of Nothofagus as well) is in 
Antarctica---and the vast majority of the evidence for that is buried under 
thick sheets of ice.

    He also likes the idea of a "main massing" for the spider genus Migas in 
New Zealand.  Part of its diversity there is probably due to a radiation 
with little competition, and partly because of Dr. Wilton's intensive search 
for them in New Zealand (and they are difficult to find).  It certainly 
doesn't indicate to me that genus Migas originated in New Zealand.  Again, 
an origin in Antarctica wouldn't surprise me, but extinction there (and 
elsewhere) has wiped out most of the evidence.
     Panbiogeography simply seems to overestimate the role of vicariance in 
New Zealand's biota, and attacks or ignores most evidence that indicates 
dispersal.  Panbiogeography's main Achilles heel in the Southern Hemisphere 
is Antarctica.  It is a large and centrally located continent where huge 
numbers of taxa originated, but we can't prove it due to the massive (albeit 
gradual) extinction
of most of its former biota, and ice covers most of what fossil record there 
might be.  I think panbiogeographers are carrying the idea of vicariance TOO 
far, and that they "doth protest too much" when they claim dispersal doesn't 
play a major role as well (especially in New Zealand).
     ----Ken Kinman

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