Agreement Finally!!? (was Paraphyly)

[Ken Kinman]

Tom,
     This really pleases me.  The only thing that is separating us is a
trivial semantic thing which is easily corrected.  Every time we recognize a
synapomorphy as being the origin of a clade, I would call that a "cut".  But
hey, let's just call it a "boundary" so we can avoid the semantics.
      We all seem to agree that the "evolutionary origin of the amniotic
egg" is a good place (minimally arbitrary) to recognize a taxon "boundary".
This is the origin of a clade (Amniota).
      The only difference between us eclecticists and the you strict
cladists is that we also find it useful to regard that very same "boundary"
as the termination of a taxon (in this case Amphibia).  Strict cladists want
all taxa to be "open-ended" (i.e., all boundaries are origins only), while
the rest of us want to regard some of those same boundaries as terminations
as well (for a variety of reasons).   Sadly, this is what we have been
fighting over for more than three decades, and it could be so easily
reconciled with a simple cladisto-eclectic compromise.  (NOTE: another quick
semantics thing--- maybe if we called them "truncated clades" instead of
paraphyletic groups, that would make them a little more palatable?  I think
I'll try that out below).
      Anyway, we can compromise by using the kind of markers (for exgroups)
used by myself and Michael Benton, and not only do we have the advantages of
sometimes using "boundaries" as terminations, but we don't have to lose any
cladistic "nesting" information.  My {{Tetrapoda}} marker in Class
Sarcopterygea shows that we evolved from the fleshy-finned fishes; and my
{{Gnathostomata}} marker in Class Agnathea shows that we are craniate
vertebrates, the major clade of Phylum Chordata (Kingdom Metazoa).***
     The only question in my mind is which boundaries are the most
uncontroversial and useful as terminations of major "truncated clades" (I
minimized their number until an optimum seems to be reached, but going to
zero can often crash the optimality to zero, as I have already argued).  By
simply allowing explicit truncated clades (and their corresponding
exgroups), the strict cladists would no longer be "strict", and we could
spend a lot more time cooperating.  But eclecists must meet them half way by
explicitly labelling their truncated clades (a.k.a. paraphyletic taxa) with
exgroup markers.  It's really quite simple once you clear away the semantics
that keep us from understanding each other's point of view.
           ----  Cheers,  Ken Kinman

***My alphanumeric coding stores precise cladistic (sister group)
information for both the taxa and the markers.  For example, the {{Amniota}}
marker is coded as sister group to the amphibian Order Diadectiformes.  And
the {{Gnathostomata}} marker is coded as sister group of the Order
Osteostraciformes (Class Agnathea).
     And I still code the {{Eukaryota}} marker as sister group to Order
Sulfolobales (Class Crenarchaea; Phylum Metabacteria) based on the widely
held view that the eukaryotic host cell evolved from a metabacterium (a.k.a.
"archaebacterium").  The particular metabacterial group that is sister group
to Eukaryota is still uncertain, so my coding may have to be modified if
Sulfolobales is not actually the closest relative.  This coding can absorb a
lot of future changes, thus maximizing information while it also minimizes
instability.  Stability and progress can successfully co-exist.   And just
think of the coding as representing an abbreviated cladogram on the left
side of the classification.  You can even replace the alphanumeric code with
cladogram lines if you want.
     Finally, I should point out that the coding can work just as well for
intermediate categories like subfamilies, superorders, or whatever.  I just
think intermediate categories should have been coded (rather than named) all
along, since it greatly streamlines the formal nomenclature.  And my uniform
endings for higher taxon names are just another proposed option (and is
still just "pie in the sky" until we solve our other differences).  The
Kinman System does not require standardized endings at these higher
categories (or the elimination of intermediate categories).  However, I
think this would be a useful legacy to hand down to future generations, but
that is just my long-term optimism making one of its very rare appearances.


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