[Taxacom] Poor flying hoatzins dispersed (on flotsam) from Africa to S. America?

[Kenneth Kinman]

Dear All,
      A very recently published article provides a probable example of a
major taxon (Order Opisthocomiformes) establishing itself in South
America having drifted on flotsam from Africa during the Cenozoic.
Unlike other such cases, this involves a bird (and a poorly flying one,
and with a life style which makes it a perfect candidate among birds to
have made such a trip).    
     At first, I was frankly a bit skeptical, as this dispersal would
have taken place tens of millions of years ago, and thus not quite the
"slam-dunk" example of a Nile crocodile making the same dispersal trip
much later in time.  There is also the problem that the closest
relatives of the hoatzin are still very uncertain.   
     However, in spite of my initial wariness, I believe it more likely
that the hoatzin family (presently classified in a monotypic Order) most
likely did (as the this paper suggested) originate in Africa and
introduce itself into South America by flotsam dispersal across the
Atlantic Ocean (and then subsequently went extinct in Namibia, or any
other parts of Africa in which it may have originally lived).  If there
is another equally likely (or more likely) explanation for this new
information on hoatzin origins, I would certainly find it interesting
(given my initial skepticism about such an unexpected hypothesis).
However, at present I am inclined to see it as yet another case of
unexpected dispersal (not vicariance).  Anyway, see one discussion of
this recent paper through the weblink below.        
              -----------Ken Kinman    

http://www.sciencedaily.com/releases/2011/10/111004175929.htm