[Taxacom] basal arthropods?

[Kenneth Kinman]

 Dear All, 
         On a related subject (the evolution of early
arthropods, which seems to be almost as misinterpreted as early Mollusc
evolution), I found that a couple of papers on Anomalocarids were
published last year. Unfortunately, they are not open access, but from
what I can glean from abstracts and other available information, I
seriously doubt that they would cast much reliable light on the reality
of arthropod origins (and certain conclusions seem to be more
disinformational and not helpful at all, as related below).  However,
the popular scientific press (in particular) loves to feed on this kind
of thing.     
        I am particularly perturbed by the suggestion
that genus Schinderhannes of the Devonian (which I admit is interesting
in that it considerably extends the fossil record of Anomalocarids to
the Devonian) indicates that Anomalocarids or a slightly more inclusive
clade of "great-appendaged arthropods" is paraphyetic with respect to a
clade including "ALL" other arthropods.    
        Are you kidding me??  Schinderhannes may have developed some
characters convergently with "euarthropods", but that such large (and to
my mind, relatively derived) arimals that late in time provide any
significant information about the origin of Euarthropoda (or Arthropoda
as a whole) seems simplistic and naive. It is couched in phylogenetic
terms and analyses, but that doesn't make it scientifically valuable.
That many science writers and the public might eat up this kind of thing
is not surprising, but it is disheartening.             
       Frankly, there is a lot of phylogenetic garbage out
there which purports to list perceived synapomorphies, but in the long
run (especially among fossil forms), cherry-picking certain characters
probably often leads to wrong conclusions that have little to contribute
to the real phylogeny (and diverts us from real progress), That anything
like an Anomalocarid gave rise to Phylum Arthropoda or Euarthropoda
should be viewed with extreme skepticism. Schinderhannes will no doubt
greatly contribute to the phylogeny of Anomalocarids, but suggestions
that it has anything to do with the origins of Arthropoda seems likely
to be more a diversion which actually does more harm than good, It sort
of reminds me of Sereno's analyses which suggested that Tyrannosauroids
were closer to the origin of birds than they actually were.  Such
suggestions were highly criticized by other dinosaur phylogenetifists,
and rightly so in my opinion.  The same will likely prove true of any
Anomalocarid (especially Schinderhannes) indicating that any
Anomalocarid (especially one as late as Schinderhannes) has anything to
contrbute to the early evolution of Arthropoda back in the PreCambrian.          
       Granted that the sparsity of the fossil record can result in the
apparent absence of "ghost lineage" forms, but that such a problem
exists in this case is frankly hardly credible.  Such fossils are rather
popular because they are relatively large and bizarre (somewhat like
tyrannosaurs), but size and popularity hardly make them scientifically
more valuable.  Actually, it can make them disinformational when TOO
MUCH attention is devoted to them.  The popular press inflates the
importance of the large and weird, and that can affect funding that
diverts funding towards them, and often away from the small (but
fundamentally more important) taxa.   
      Therefore, it is no great surprise that the popular press would
miss any subtleties which "de-arthropodization" might complicate the
issue (but it still mystifies me how many biologists fail to see such
problems).  That so much of the scientific establishment (and their
governmental funders) seem so completely captivated by
"arthropodization" that "de-arthropodization" almost never gets a second
glance (much less funding) is unfortunate.  It's frankly like trying to
fight the excesses of capitalism before it imploded in 2008.  Greed
seems to be more influential in today's world than truth, and as in
politics, it seems to be increasingly affecting science as well.
Sometimes the greed factor can sometimes be obvious, but even more often
be very subtle, and it can even influence scientists who might not
realize how much it has scientifically restricted both themselves and
colleagues whom they respect.  The problem is more pervasive and
widespread than we would like to think.      
          --------Ken Kinman