[Taxacom] Genus Homo (how many species?)

[Kenneth Kinman]

Dear All,
      Not surprisingly, how many species of genus Homo to recognize
makes it one of the most controversial genera in systematics.  It seems
that there are three main species upon which almost everyone agrees: (1)
Homo habilis; (2) Homo erectus; and (3) Homo sapiens.  Whether
neanderthals constitute a separate species is much debated, but that is
not what I am most interested in here.
      I am more interested in opinions on whether it is best to
recognize two intermediate species: Homo ergaster (between H. habilis
and H. erectus), and Homo heidelbergensis (between H. erectus and H.
sapiens).  I am personally inclined to include heidelbergensis within H.
sapiens (as H. sapiensis heidelbergensis), but I haven't made up my mind
about Homo ergaster (as a species or as an early branching subspecies of
Homo erectus).
       --------Cheers,
                         Ken