Re: Gondwana Split Sorts Out Mammalian Evolution

["Ken Kinman" <kinman@hotmail.com>]

     Molecular systematics is indeed revolutionizing our understanding of 
the interrelationships among mammalian Orders.  And the K-T extinction 
probably "shaped" the course of mammalian evolution in the same way it 
shaped bird evolution--- namely, massive extinction globally, but most 
surviving clades in the southern hemisphere.  Therefore the "boreoeutherian" 
radiations in the north were probably more "explosive" than the older mammal 
groups in the south.
     The ungulates are clearly a polyphyletic group (the afrotherian 
"Pseudoungulata" clearly arose separately from the "real" ungulates up 
north).  This splitting of the traditional "Ungulata" is probably one of the 
biggest surprises to many morphologists, who believed that hyraxes 
(pseudoungulates) were closely related to perissodactyls.  Thus McKenna's 
clade Altungulata appears to be highly polyphyletic (based on homoplastic 
convergences and plesiomorphies).
    Yesterday's synapomorphies and clades can become today's polyphyletic 
trash.  Another reason I think there are way too many names (superordinal in 
this case), and coding is preferable (I still have the same mammalian 
Orders, but just have to put them into a different sequence).  Giving formal 
names to all these high clades is not a good idea, and informal names like 
"boreoeutherians" would be just as useful.
          -----  Ken Kinman

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