Art,
 
Read Emilio's Dr Mayr (yeah, I know you read the book, but try the short
paper again, it really is pretty good), he presents an easy to understand
concept of species.  I think we can use his definition - especially the
whole bit on geographic isolation not being a determinant.  Also he never
mentioned a particular animal in his definition; thus his definition
applies to all.
 
Tom Eichhorst in New Mexico, USA