[Taxacom] Geophylogeny

[Ken Kinman]

Dear All,
      I think we might be in danger of getting bogged down in the semantics 
of the phrase "informative character".  Biogeographical information can be 
informative, but I certainly wouldn't want to see it used as a character in 
a phylogenetic data matrix.

      But it's always fascinating to see geographical patterns emerge, such 
as the afrotherian mammal clade.  However, I suspect that the name 
Afrotheria may be somewhat misleading, and that fossils may show two or more 
clades of afrotherians independently invading Africa from Eurasia.  Some of 
the genera presently classified in Hyopsodontiformes may need to be 
transferred to the appropriate afrotherian Orders.  For all we know, the 
sister group to the afrotherian clade might be a North American hyopsodontid 
group.  The present concentration of afrotherians in Africa could very well 
be the result of Africa providing a refuge for this group during and after 
the end-Cretaceous extinction.

     That's why extrapolating from present distributions can be a risky 
proposition, especially if the taxa involved arose in the Mesozoic.  Even 
for vertebrates with relatively well-studied fossil records, but who would 
have guessed we would eventually find the earliest hummingbird fossils in 
Europe!!  Organisms with poorer fossil records can be far more difficult.  
Anyway in the long run, different lines of evidence will eventually become 
congruent, but in the short run they can often seem to conflict with one 
another in very frustrating ways.
  -----Ken

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