Neogondwana and Epitheria

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

    Extrapolating the mammal results to birds is a tricky business, beyond 
the general "southern refuge" at K-T.  Even for mammals, I am not completely 
convinced that Afrotheria is necessarily the most basal group.  The 
Xenarthrans of Neogondwana have been classified separately from all other 
living mammals (epitheres) for quite some time, and it still seems possible 
to me that xenarthrans paraphyletically gave rise to both afrotherians and 
boreoeutherians, either separately (more likely?) or as a single epitherian 
clade (epitherian synapomorphies have always been rather "iffy" in my view, 
but who knows).
    So I wouldn't jump too hastily on this new "Afrotheria came first" view 
(they may have instead been second).  And even if afrotherians are basal to 
xenarthrans, that doesn't mean the birds would necessarily show the exact 
same pattern in Gondwanan distribution.  But Gondwana (as a whole) seems to 
have clearly emerged as the main refuge for mammals and birds at K-T, so it 
is not surprising that bird and mammal paleontologists are paying more 
attention to the southern hemisphere (and for scientific reasons other than 
just the fact that it was relatively neglected for so long).
          ------  Ken Kinman


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