[Taxacom] Bye bye Crustacea

[Kenneth Kinman]

Dear All,
     There certainly seems to be an overwhelmly consensus that hexapods
evolved from crustaceans.  But whether hexapods are a single clade or
whether more than one clade of hexapods independently evolved from
different crustacean groups is still uncertain.  Collembola
(springtails) in particular could have easily  evolved hexapody from a
different crustacean ancestor than other hexapods.
        In any case, the paraphyly of Crustacea, with respect to
hexapods (and less certainly to other arthropods, such as an
arachnomorph clade?) is no reason to say bye bye to a Class (or
Superclass) Crustacea.  In view of the uncertainties that remain, that
would be even more short-sighted than abandoning a Class Reptilia.  I
don't know how PhyloCode will handle a taxon Crustacea, but unlike what
they did to Reptilia, they should certainly not make the same mistake
and hijack the name Crustacea and try to cladify it.        
      i have long been convinced that the selection of outgroups for
Crustacea (and Arthropoda as a whole) are still so uncertain, that
neither molecular OR morphological datasets can resolve the broad
phylogeny of arthropods or even the wider grouping of ecdysozoans.  I am
still convinced that most worm taxa are relatively derived and tell us
almost nothing about arthropod origins (as has long been assumed).
Exploring alternative, outside-the-box, outgroups for Arthropoda are
sorely needed for both molecular and morphological datasets.
Traditional outgroup selection just continues to yield frustration and
incompatible cladograms.   It's still a mystery even more ABOMINABLE
than that of angiosperm origins!!!  Even Darwin had little idea how
abominable arthropod origins would become, and regretfully the problem
remains largely ignored and its importance underestimated.            
            --------Ken Kinman
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Garry.Jolley-Rogers at csiro.au wrote:
This debate has smouldered ever since Cuvier.  Here's hoping its FINALLY
moving towards consensus as it makes comparative work difficult.