[Taxacom] Transatlantic rafting not uncommon

[Robinwbruce at aol.com]

Dear All,
 
The track to nowhere? Perhaps. But do we have an alternative? There is  no 
alternative! There is always an alternative! Take your pick.
 
How useful is a late middle-age/ early renaissance  (Dutch?) concept  like 
'Africa' at resolving global spatial uncertainty of distributions of biota  
with roots going back in excess of 100 million years? I only ask.
 
Post-Hutton, we have begun to unravel the uncertainties of  deep  time, 
with some degree of success, and the paradoxical logic inherent  therein, q.v. 
cladistics, anyone?  But we certainly seem to stumble  over global surface 
space again, and again, and again, superficially a much  simpler issue; after 
all, space and time co-ordinates of  global surface  were resolved by the 
fourth quarter of the 18th century (with nice maps I  agree). Hooker knocked 
on the door, Berg pushed it open, Croizat stepped  through, but we seem too 
culturally wedded to a special reality for  species (Darwin's legacy?) and 
coastlines too (geography's tyranny and  legal title?), to gain significant 
intellectual traction. It seems we want  our certainty and our uncertainty 
too. And the name we give this is  - 'explanation'.
 
Robin
 
   
 
 
In a message dated 10/21/2011 2:57:47 A.M. GMT Daylight Time,  
kennethkinman at webtv.net writes:

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  



_______________________________________________

Taxacom  Mailing  List
Taxacom at mailman.nhm.ku.edu
http://mailman.nhm.ku.edu/mailman/listinfo/taxacom

The  Taxacom archive going back to 1992 may be searched with either of 
these  methods:

(1) by visiting http://taxacom.markmail.org

(2) a  Google search specified as:   
site:mailman.nhm.ku.edu/pipermail/taxacom  your search terms  here