[Taxacom] Evolution of molluscs and other invertebrates

[Kenneth Kinman]

 Dear All, 
       I continue to be extremely disappointed that there
is still very little discussion (much less support) on the possibility
that Class Bivalvia could very well be paraphyletic with respect to
other classes of molluscs. This hypothesis is strongly advocated by
myself and by Thomas Cavalier-Smith. After several years, I still see
noone else discussing (much less advocating) this idea, especially among
malacologists who really should be those most interested in this
possibility. Is the idea that molluscs evolved from worms so entrenched
that other possibilites are simply automatically rejected out of hand?
Shipworms, for example, are recognized as molluscs because they retain
remnants of the shell.  But I suspect a number of worm taxa are also
mollusc descendants that have no such obvious remnants to readily link
them to their ancestors.                   
         As in the case of great apes, I believe whole
genomes will be the major step in determining the actual
interrelationships of the molluscan Classes (and other groups which
could be their descendants---arthropods, annelids, various worms?). As
the costs of genome sequencing continues to plummet, Phylum Mollusca
will hopefully become a primary target for analysis. Not only because it
is a diverse and economically important group, but it is probably
central to an understanding invertebrate evolution, even more so than
arthropods which tend to attract relatively more attention. 
            -----------Ken Kinman