[Taxacom] Nothofagus flying to NZ

John Grehan jgrehan at sciencebuff.org
Sat Dec 23 09:32:43 CST 2006


-----Original Message-----
From: taxacom-bounces at mailman.nhm.ku.edu
[mailto:taxacom-bounces at mailman.nhm.ku.edu] On Behalf Of Ken Kinman
Sent: Friday, December 22, 2006 4:55 PM
To: taxacom at mailman.nhm.ku.edu
Subject: Re: [Taxacom] Nothofagus flying to NZ

    Well, I think using the word "magically" is a little harsh.  

Ken,, there is nothing harsh about that at all. There is no empirical
evidence given by Knapp et al to justify transforming minimal divergence
data into maximal or absolute data. If someone can show me how
non-empirical transformations are not magic I will be interested to

I just finished skimming through the followup paper by Cook and Crisp,
2005, and although they criticized Knapp et al.'s paper on certain
grounds, they did come to the same basic conclusion:  dispersal across
the Tasman Sea during the Cenozoic (probably after previous Nothofagus
had been extirpated from New Zealand, which I guess would have occurred
around the Oligocene).

So they came to the same conclusion - but why?

     The case seems most clear for the subgenus Fuscospora.  Even if you
don't like the molecular data which groups N. gunnii together with the
New Zealand species, there is also morphological evidence linking the
New Zealand species to N. cethanica (Oligocene of Tasmania).

Evidence relating N gunnii tow New Zealand species has nothing to do
with how they got to be where they are. The relationship is not the
issue - or if it is please explain.

     So it seems to me the real debate is no longer about IF, but rather
HOW (and also when) this dispersal of Nothofagus reintroduced it into
New Zealand-----not once, but twice (one time for each subgenus that now
occurs there).  Since floating in the sea doesn't seem to work very
well, it seems to me birds are the best bet!!!

But you have not provided any empirical evidence for that belief. Just
citing Knapp et al (and I notice that you did not address my request for
a demonstration of how they made a "good case") or Cook and Crisp gives
no insight into your beliefs whatsoever. An outline of what you think
they present as constituting evidence for your dispersal beliefs would
be something that is open to evaluation.

John Grehan

    ----Ken Kinman
>From: "John Grehan" <jgrehan at sciencebuff.org>
>To: "Ken Kinman" <kinman at hotmail.com>,<taxacom at mailman.nhm.ku.edu>
>Subject: Nothofagus flying to NZ
>Date: Fri, 22 Dec 2006 13:16:31 -0500
>I would be interested to know what Ken Kinman defines as a "good case"
>made by Knapp et al 2005. As far as I can see they take fossils that 
>only represent minimal divergence dates and magically (I use this word 
>because I am unaware of any scientific process involved) turn them into

>absolute or maximal divergence dates when mapped onto a theoretical 
>molecular clock.
>John Grehan
>-----Original Message-----
>From: taxacom-bounces at mailman.nhm.ku.edu
>[mailto:taxacom-bounces at mailman.nhm.ku.edu] On Behalf Of Ken Kinman
>Sent: Wednesday, December 20, 2006 11:07 PM
>To: taxacom at mailman.nhm.ku.edu
>Subject: Re: [Taxacom] Two primitive mammals in one week
>      The paper by Knapp et al., 2005, makes a very good case that 
>long-distance dispersal of Nothofagus has occurred over the Tasman Sea.
>Nothofagus apparently doesn't like sea-water, but why has dispersal by 
>migrating birds been rejected as a mechanism in the past?  Even if 
>Nothofagus nuts are not eaten by birds today, perhaps they were eaten 
>by some migrating species of bird which is now extinct.
>    ---Ken Kinman

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