[Taxacom] final thoughts on dispersal and vicariance

[John Grehan]

Ken,


A majority opinion (growing consensus) is not a predictor that a scientific
position is necessarily correct.


There is indeed currently a lack of evidence that trans-Atlantic
relationships among differentiated taxa arose from overwater dispersal.


The ratio of dispersal to vicariance has never been shown to be high. It is
just invoked.


How would one 'explore' the conjecture that aplocheiloid fish rafted from
Africa to South America?


What 'growing pattern of occasional raftings across an early (narrower)
Atlantic ocean'?


I am not aware of "growing amounts of evidence that caviomorph rodents and
New World monkeys resulted from such raftings." All the literature I have
seen to date just says so out of a belief or based on fictional divergence
dates. I will look that the link and comment later.


Ken - you are not, and have never been, under any obligation to convince
anyone of anything. And you are also not under any obligation to contribute
to any discussion. If it interests you to do so then fine, if not then
don't. Better than complaining about the pain.


John Grehan


On Wed, Apr 9, 2014 at 2:57 AM, Ken Kinman <kinman at hotmail.com> wrote:

>
>
>
> Dear All,
>        Thanks to Jason in particular for his various posts on this
> subject.  And I agree that documenting evidence for a lot of dispersals
> will take decades (especially the rare ones across the early Atlantic
> between Africa and South America).  However, it seems like there is a
> growing consensus that panbiogeographers have clearly overplayed the role
> of vicariance concerning the post-KT fauna of Madagascar (vertebrates in
> particular, where the ratio of dispersal to vicariance seems very high).
>        As for my suggestion that aplocheiloid fish could have rafted from
> Africa to South America, it is just an hypothesis (not a theory), but I
> consider it an exciting new possibility to explore.  Panbiogeographers like
> patterns, so I would think a growing pattern of occasional raftings across
> an early (narrower) Atlantic Ocean would actually interest them, but they
> continue to even attack growing amounts of evidence that caviomorph rodents
> and New World monkeys resulted from such raftings.  One recent paper on the
> fossil evidence regarding caviomorphs is quite interesting and quotes
> literature on that debate (see weblink below).
>        Anyway, I am frankly tired of trying to convince John and Michael
> that overplaying the importance of vicariance (especially with regard to
> Madagascar) is counterproductive, and perhaps makes a lot of people less
> inclined to read their papers.  So I don't plan to post anything further on
> dispersal and vicariance.
>                     ---------------Ken Kinman
>
>
> http://rspb.royalsocietypublishing.org/content/early/2011/10/08/rspb.2011.1732.full.pdf
>
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