[Taxacom] Columbiformes, ghost moths, Madagascar, etc.

[Michael Heads]

Hi Ken,
  
You say: 'Those interested in vicariance are best advised not to touch this one with a
ten-foot pole. Many older taxa that are more likely to provide useful information on vicariance would be a better bet by far'.  
 
My own experience is that pigeons and parrots are two of the best groups for studying vicariance, as the patterns are simple and clear. If you learned just these two groups you would have a good idea of tropical biogeography and the main patterns. The phylogeny of ‘the clade that shouldn't be touched’ (incl. 'Raphidae' etc.) is: 
  
Otidiphaps: New Guinea 
(Trugon: New Guinea 
(Goura, the largest pigeons, with spectacular head-dress: New Guinea. 
(Didunculus: Samoa 
(Caloenas: Nicobars, fossil on New Caledonia and Tonga 
(Raphus: Mauritius - dodo, extinct  
Pezophaps: Rodrigues, extinct))))) 
  
A widespread Indian Ocean/SW Pacific group diverged first around the New Guinea terranes (the first three breaks), then the Samoan clade broke from the rest (at the Pacific plate margin), and finally there was a split between the Nicobars and the Mascarenes. This last is an important break and is related to the well-known connection: southern Africa - Burma that also skips India/Sri Lanka.  
 
Goura is bright blue and the largest pigeon extant. It has spectacular head-dress (see shot at Wikipedia), the last trace of the casque of the cassowaries and other dinosaurs. (Reduction and fusion in  the cranium is one of the main trends in vertebrate evolution). New Guinea has usually been seen as a 'sink' in dispersal theory, with a biota made up of waifs and strays that arrived from elsewhere in recent times. The traditional view is that no New Guinea clade can have any fundamental phylogenetic significance, as they are all so young and derived. But now molecular studies show that clades there are sister-group to global groups, not derived within them, and that clades such as birds of paradise have an 'unexpectedly long history' (Irestedt et al., 2009).  
 
  The current distributon of the Goura lineage is restricted to New Guinea, but this has been tectonically narrowed fropm a prior, wide ramnge. The Goura ancestral complex was widespread through the Mesozoic Pacific and evolved on the Australian craton part of New Guinea plus island arcs, intraplate volcanics etc., some of which eventually came together to form New Guinea.     
  
Michael 

Wellington, New Zealand.

My papers on biogeography are at: http://tiny.cc/RiUE0

--- On Thu, 26/5/11, Kenneth Kinman <kennethkinman at webtv.net> wrote:


From: Kenneth Kinman <kennethkinman at webtv.net>
Subject: Re: [Taxacom] Columbiformes, ghost moths, Madagascar, etc.
To: taxacom at mailman.nhm.ku.edu
Received: Thursday, 26 May, 2011, 2:09 PM


Hi Lynn,
       Thanks, I had seen some of the earlier papers which they referred
to, but not that particular paper.  Seems like molecular (as well
morphological) research shows that the classification of Order
Columbiformes is long-overdue for a major overhaul.        
       Although I am obviously not philosophically opposed to one
paraphyletic (mother) family giving rise to another family, a huge
Family Columbidae giving rise to a tiny, highly derived Family Raphidae,
is totally the antithesis of a useful classification.  Therefore not a
mother-daughter pair that I would think anyone would advocate
maintaining.  It's certainly nothing like Class Reptilia giving rise to
Class Aves (the latter being highly diverse, as well as worldwide in
distribution).
     But it clearly has taken (perhaps far too long) for molecular data
to finally address this imbalance in columbiform classication.  How many
families of Order Columbiformes is optimal remains to be seen (certainly
more than two), but whether "Raphidae" remains as a full family, or
subfamily, or even tribe, remains to be seen.  
        In any case, this study and others seem to indicate that
biogeographic (and other) claims that Raphidae have an extensive ghost
lineage (as though it might be sister group to Family Columbidae) have
no credible basis at all (simply based on very derived morphological
characteristics which rapidly evolved due to insular isolation).  Those
interested in vicariance are best advised not to touch this one with a
ten-foot pole.  Many older taxa that are more likely to provide useful
informaton on vicariance would be a better bet by far.    
           ---------------Ken                            
  -------------------------------------------------------
Lynn Raw wrote:
       BTW, have you seen this paper
http://sysbio.oxfordjournals.org/content/56/4/656.full.pdf 

On 24 May 2011, at 22:33, Kenneth Kinman wrote: 
> Hi Michael,  
>       (1)  I wasn't suggesting that the fossa could have >eliminated 
> Columba on its own, but along with other predators (like >the
mongooses, 
> civet, etc.).  And again, I suggest that it wasn't >necessary to 
> eliminate a well-established Columba species if the >predators simply 
> prevented the population from being well-established in >the first
place 
> (nipping the population in the bud, so the speak).             
>     (2) Yes, I think there are plenty of cases of >vicariance
explaining 
> the distribution of taxa, instead of dispersal.  The New >Zealand
wrens 
> that we discussed is a great example.  But Madagascar >became isolated 
> much earlier than New Zealand, so I think the vertebrate >fauna of 
> Madagascar (especially mammals and birds) is much more the >result is 
> dispersal.  I would expect more vicariance among the other >vertebrate 
> groups which have been around longer (Jurassic or >earlier).  
>         -------Ken               
> -------------------------------------------------------- 


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