[Taxacom] Transatlantic rafting not uncommon

[Kenneth Kinman]

Dear All,
      I guess this thread is getting nowhere.  Be careful what you ask
for.  I asked for a shred of evidence, and I am referred to one small
shred in an older paper (Macey et al., 2004) based on a very limited
sample of species and only on mitochondrial sequences.  Doesn't seem to
matter that Vidal et al (2007) and Muller et al. (2011) considerably
expanded the number of species sampled and more gene sequences----they
dared to challenge the primacy of vicariance, and that is apparently a
no-no in panbiogeography circles.  
       So I guess panbiogeographers (at least the ones that I am familar

with) prefer old data in older papers, as long as they have "nice maps"
and don't challenge some of their favored vicariance conclusions.
Anyway, I certainly don't think that "repeated patterns are
meaningless".  However, I don't discriminate against dispersal patterns
in favor of vicariance patterns.  The truth is almost certainly going to

be a mix of the two for many taxa (much to the discomfort of those who
are heavily invested in vicariance patterns and seem to have a visceral
reaction to dispersal patterns that might be challenging them).              
                ---------Ken Kinman                             
P.S.  I am not holding my breath for any fossil Amphisbaenians at all in

the uppermost Cretaceous, much less earlier (before South America and
Africa separated).  I just can't believe that Cretaceous amphisbaenians
(if they existed at all) were less fossilizable or less discoverable
than those throughout the Cenozoic.  These are not the kind of animals I

would expect to have undiscovered ghost lineages.  Those who think such
a ghost lineage exists in this case are probably indulging in wishful
thinking.  So in my view, I am siding with authorities with the widest
sampling of taxa and data, and those citing "authorities" basing
conclusions on less sampling and less data would do well to put up or
shut up.
       
-----------------------------------------------------------
Michael Heads wrote:
Hi Ken, 
?      Your?evidence for amphisbaenians not being present in the
Cretaceous is derived from?(1) a literal reading of the fossil record
(fossil age = clade age), and (2) the argument from authority (Vidal
etc. are the acknowledged experts on the group, therefore they are
right. Exposing fundamental flaws in these authors'?logic
is?irrelevant 'nitpicking' because they 'actually study the group').
? 
Accepting?a literal reading of the fossil record implies that
biogeography is caused by random trans-oceanic dispersal and that any
repeated patterns are meaningless. There is a vast amount of evidence
for amphisbaenians and other groups being much older than indicated by
their fossil? record (and fossil-calibrated clocks),?but you don't
accept biogeographic?evidence as it is?all?caused by?chance. So
why are more and more authors putting distribution maps in their
abstracts at Molecular Phylogenetics and Evolution??Are all these
simple, clear-cut distributions really just due to chance? If they are
not, this suggests?that a?literal?reading of the fossil record
might be?misleading. One?interesting study of amphisbaenians (with
very nice maps) concluded: 'Old and New World Amphisbaeniidae ... are
monophyletic, so that this family dates back at least to the opening of
the Atlantic Ocean 80 MYBP'.?(Macey et al, Mol. Phylogen. Evol. 33:
22. 2004).? 
?? 
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: Friday, 21 October 2011 4:44 AM 
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