[Taxacom] Panbiogeography

[Ken Kinman]

Hi Michael,
         I don't know much about the debate concerning killifish biogeography, but assume (since you brought it up) that it must still be controversial (as with the cichlid fishes we discussed previously).  I can certainly see how the killifishes could be one of the few taxa which survived on Madagascar during the K-T extinction which killed off so many other vertebrates there.  Especially since some killifish can enter diapause during periods of drought and/or starvation. 
        Are you asking my opinion whether I side in this particular case with the dispersalists or those advocating vicariance?  If so, I would have to look at the dispersalist arguments on the other side of the debate.  Are there any recent papers still suggesting dispersal played a major role in the broad (worldwide) biogeography of killifish?   Sounds like an interesting debate.             
                           --------------------------Ken                              
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> Date: Fri, 4 Apr 2014 10:39:23 +1300
> From: m.j.heads at gmail.com
> To: taxacom at mailman.nhm.ku.edu
> Subject: Re: [Taxacom] Panbiogeography
> 
> Hi Ken,
> 
> The aplocheiloid killifish illustrate a standard pattern, with two main
> clades (Fig. 2-3 in my 2012 book). One is in America, and (another
> subclade) mainland Africa. It's not in Madagascar, and you might
> assume that this was the result of extinction there. But the other main
> clade is in Madagascar and the Seychelles, and also (another
> subclade) from India to Java.
> 
> You could explain the pattern by chance dispersal from anywhere within the
> whole range, e.g. Guatemala or Gabon or Goa. Chance dispersal is not
> related to any other factor, and so this wouldn't make any particular
> predictions.
> 
> As an alternative, both groups could have been everywhere to begin with,
> and you could explain the pattern by the chance extinction of the first
> group from Madagascar - Java, and the chance extinction of the second group
> from America and Africa. This would predict fossils in the area of absence,
> but none have ever been found. It's also difficult to imagine why one group
> would go extinct in an area that is exactly allopatric with the area where
> the other group went extinct. This explanation also leaves the original
> differentiation of the groups unaccounted for.
> 
> Or you could explain the pattern by simple vicariance, with the first break
> located between Africa and Madagascar, at the Mozambique Channel. This
> would make the general predictions that other groups would show similar
> patterns, and that there would be a simple correlation between the pattern
> and tectonics, climate or some other environmental factor. Note that the
> first break, between Africa and Madagascar, comes before the secondary
> breaks (between America and Africa, and between Madagascar-Seychelles, and
> India - Java). This is congruent with the continental breakup sequence.
> 
> Michael
> 
> 
> 
> On Thu, Apr 3, 2014 at 11:17 AM, Ken Kinman <kinman at hotmail.com> wrote:
> 
> > Hi Juerg,
> >        Well, certainly not a nude rock.  However, as I explained in an
> > earlier posting, the end-Cretaceous extinction wiped out a lot of taxa
> > (most vertebrates and probably all mammals).  This left it with a lot of
> > empty niches which new mammals and birds, etc. would fill during the
> > early-to-mid Tertiary.
> >         But I suppose John would deny that the end-Cretaceous extinction
> > was that bad in Madagascar.  I am giving up arguing with him about
> > Madagascar, because he just repeats the same old fallback positions, and
> > now claiming that there is no "analytical evidence" for dispersal to
> > Madagascar.  It might not be strictly analytical evidence according his
> > definition of analytical, but there is plenty of evidence.  He simply
> > refuses to accept any of it.   I should have given up trying to reason with
> > him a long time ago.
> >                       -------------------Ken Kinman
> >
> > -----------------------------------------------------------------------------------------------------
> > > From: demarmjc at hotmail.com
> > > To: taxacom at mailman.nhm.ku.edu
> > > Date: Wed, 2 Apr 2014 17:00:29 -0400
> > > Subject: Re: [Taxacom] Panbiogeography
> > >
> > > Seeing the comments by our dispersalist friends, I wonder then, whether
> > Madagascar was empty, a piece of nude rock, before the "great migration"
> > out of Africa?
> > > Juerg De Marmels
> > >