[Taxacom] Transatlantic rafting not uncommon

Thu Oct 20 10:57:24 CDT 2011

Ken,

No doubt Mike will have his own response, but with respect to your comment that "If you or John can offer a shred of evidence to counter the views of these specialists in amphisbaenian evolution, I would like to hear it" I think you are being disingenuous to demand positive evidence when the molecular dispersalist do not. They only have minimal dates, from which they then impose a particular faith about their meaning, as you do also. 

The empirical point is that the minimal dates do not preclude an earlier origin, and when these individual instances match up to patterns in general for plants and animals of different means of dispersal, and show spatial correlations with Mesozoic tectonics, one does indeed have a basis to suggest another minimal estimate. 

There are plenty of examples of fossils turning up that are many millions of years older than the date of origin that was "previously thought" (to quote the often used clich?). Most extant species of plants and animals have no fossil record whatsoever. I guess they all evolved only yesterday!

As for "Otherwise, I have to go with the evidence published by these various herpetologists who actually study this group" there is a difference between being an expert on the molecules of some group and having expert knowledge and understanding of biogeography.

John Grehan

-----Original Message-----
From: taxacom-bounces at mailman.nhm.ku.edu [mailto:taxacom-bounces at mailman.nhm.ku.edu] On Behalf Of Kenneth Kinman
Sent: Thursday, October 20, 2011 11:44 AM
To: taxacom at mailman.nhm.ku.edu
Subject: Re: [Taxacom] Transatlantic rafting not uncommon

Hi Michael,
       Well, the clades "could" perhaps be older than they estimated,
but I doubt "much older" if you are suggesting that these families split

up during the Cretaceous.  Amphisbaenians have a pretty good fossil
record in the Cenozoic, and only the most basal family goes back to the
Middle Paleocene.  So where is the fossil record of all these families
in the Cretaceous?  I doubt that they exist, because the living families

increasingly appear to have split up during the early-to-mid Cenozoic.  

        And I'm not talking just about Vidal's paper.  Take a look at
the recent paper published by Muller et al., 2011, in Nature, describing

Cryptolacerta (an Eocene fossil which appears to be part of the sister
group to Amphisbaenia).  Their phylogeny and timeline (based on both
morphological and molecular data) indicates that Amphisbaenia originated

near the beginning of the Cenozoic, with the basal family Rhineuridae
splitting off in the early Paleocene from the clade containing the other

families.   

        Sure, this basal split could have occurred in the uppermost
Cretaceous, with Rhineuridae and the other clade both surviving the
end-Cretaceous extinction. However, neither the fossil record nor
molecular data supports your position that it happen even earlier than
that (before Africa and South America separated).  If you or John can
offer a shred of evidence to counter the views of these specialists in
amphisbaenian evolution, I would like to hear it.  Nitpicking at their
papers is easy, but let's here some solid evidence from you that
Amphisbaenia even existed (much less diversified) before Africa and
South America separated.  Otherwise, I have to go with the evidence
published by these various herpetologists who actually study this group,

and whose conclusions generally make sense to me and are backed up by a
variety of data.
          ------------Ken Kinman

-------------------------------------------------------

Michael Heads wrote:  
      Exactly. So the Vidal study was flawed,?the clades could me much

older than they estimated, and simple trans-Atlantic vicariance could be

the explanation fot the allopatry. 
Michael 
Wellington, New Zealand. 
My papers on biogeography are at: http://tiny.cc/RiUE0 
________________________________ 
From: Robin Leech <releech at telus.net> 
To: 'Michael Heads' <michael.heads at yahoo.com>; 'Kenneth Kinman'
<kennethkinman at webtv.net> 
Cc: taxacom at mailman.nhm.ku.edu 
Sent: Thursday, 20 October 2011 2:56 PM 
Subject: RE: [Taxacom] Transatlantic rafting not uncommon 
Which, I think, is normal.? A species has to get there.? Nothing
says it has to evolve quickly once it gets there. 
Robin 
-----Original Message----- 
From: taxacom-bounces at mailman.nhm.ku.edu 
[mailto:taxacom-bounces at mailman.nhm.ku.edu] On Behalf Of Michael
Heads Sent: October-19-11 7:27 PM 
To: Kenneth Kinman 
Cc: taxacom at mailman.nhm.ku.edu 
Subject: Re: [Taxacom] Transatlantic rafting not uncommon 
Hi Ken, 
? 
The phylogeny in the Vidal study was calibrated by assuming that
Caribbean island endemic squamates cannot be?older than their islands.

But other studies (Thorpe et al., 2005 Mol Ecol, 2008?Mol. Ecol.) have

dated?Caribbean island endemic squamates as?older than their
islands. ? 
Michael Heads? 
Wellington, New Zealand. 
My papers on biogeography are at: http://tiny.cc/RiUE0 
________________________________ 
From: Kenneth Kinman <kennethkinman at webtv.net> 
To: taxacom at mailman.nhm.ku.edu 
Sent: Thursday, 20 October 2011 1:57 PM 
Subject: Re: [Taxacom] Transatlantic rafting not uncommon 
John, 
? ? ?? As for Renner's work, just do a google search for:?
Renner 
transatlantic dispersal.? Lot's of interesting stuff pops up.? ?
? ? ? ? ? ? ? ? 
? ? ? And for amphisbaenian biogeography in particular, I would
strongly recommend reading the 2008 paper by Vidal (Biol Lett.,
4:115-118), which is freely available online.? I am not sure I will
completely agree with their phylogeny and conclusions (this is one group

I want to look at more carefully when I have time).? However, they
make a very good case that purely vicariant explanations of
amphisbaenian evolution and biogeography are very problematic (and
overly simplistic) in the face of more recent data.? And more than one

transatlantic dispersal was almost certainly involved during the
Cenozoic.? ? 
? ? ?? And although I was initially surprised that such
subterranean lizards rafted across the Atlantic, I am not so surprised
after thinking about it today.? Massive land slides giving rise to
large rafts of trees would wash large masses of soil along with them.?

Worm lizards washed out in such an event would have to clamber onto a
raft of trees or perish in the sea.? Burrowing into soil is sort of
like swimming, so I doubt they would have much difficulty swimming in
water when their life depended on it.? The trees would also usually
have insects upon which to feed if the lizards got hungry enough (even
if not the kind of insects they normally would eat).? I don't find it
all that terribly mysterious. Anyway, I look forward to learning more
about these lizards.? ? 
? ? ? ? ? ? ? --------Ken? 
---------------------------------------------------- 

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