[Taxacom] North America, Central America + S.E. Asia sister taxa

[John Grehan]

bounces at mailman.nhm.ku.edu] On Behalf Of Kenneth Kinman
Sent: Thursday, December 29, 2011 10:06 PM

>It is not surprising that there are so many such Pacific patterns,
> since there are a number of different ways by which they could have
> arisen, including northern Beringian dispersal, southern Antarctic
> dispersal, or even direct dispersal across the Pacific (as well as
even
> broader original distributions undergoing severe geographic extinction
> of intermediate taxa).    

There is a difference between an imagined 'could have' and reality.
  
> Interestingly, any of the three mentioned below (Enicoscolus,
> Pitnus, and Batis) seem to me to be good candidates for direct
dispersal
> across the Pacific via rafting.  Pitnus are leaf-miners which could
feed
> on the leaves of rafting trees, Batis plants are a good candidate to
> survive on rafts since they are extremely salt-tolerant, and even
> Enicoscolus larvae could easily feed on the dying matter in such
rafts.
> Not at all surprising that Pitnus is even found in the Galapagos.   


Ken gives a wonderful illustration of exactly how dispersalists tie
themselves up in knots, but claiming an excellent dispersal ability and
then having to explain away why such 'good' dispersers are not even as
well dispersed as supposedly poor dispersers, and why such good
dispersers are not everywhere else. Nonsense generates nonsense.

John Grehan
 
               --------Ken
----------------------------------------------------------

John Grehan wrote:   
     This observation points out the reality of Pacific patterns. The
NG/Aust-C America distribution is relatively unambiguous with respect to
the main massings being immediately adjacent to the Pacific basin. In my
Galapagos study I found the saltwort genus Batis to also be in north
Queensland/Papua NG as well as Central America/Baja
California/Galapagos/Caribbean/Atlantic Brazil. 
The central USA-SW Australia pattern is less unambiguous as it is not
obvious which ocean basin is involved. Further outgroup comparisons
might help. Also in my Galapagos study I found the genus Pitnus recorded
from the Caribbean/Central America/W Mexico/SW USA/Galapagos and
southern/SW Australia. 
Trans Pacific patterns are almost beyond counting, being so frequent and
taxonomically broad. 
John Grehan 
-----Original Message----- 
From: Don.Colless at csiro.au [mailto:Don.Colless at csiro.au] 
Sent: Friday, December 23, 2011 11:28 PM 
To: John Grehan 
Subject: RE: [Taxacom] North America, Central America + S.E. Asia sister
taxa 
As a minor contribution to this thread, may I record the genus
Enicoscolus, with a species in Papua-New Guinea and North Queensland and
the rest in central America. I cannot conceive this as due to
convergence. There is another genus, name forgotten for the moment, with
a species in central USA and one in SW Australia. The identity was
confirmed  by a very surprised - and eminent - North American Dipterist.

Donald H. Colless 



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