[Taxacom] Disappointing "Deep Arthropod Phylogeny"
kennethkinman at webtv.net
Fri Feb 12 21:01:25 CST 2010
I am EXTREMELY disappointed by he initial results of project "Deep
Arthropod Phylogeny" published this week in the journal Nature. I'm
sure they are building an excellent molecular database, but whether it
is getting them any closer to actually resolving arthropod
interrelationships is very doubtful in my opinion.
The main problem is probably a FALSE ASSUMPTION. Namely that
they should be using tardigrades and onychophorans as their outgroup
taxa. They did actually have enough sense not to include pentastomids
in the outgroup, because that group has been shown to be derived from
crustaceans, and therefore an example of what I have called
Unfortunately, tardigrades and onychophorans are probably ALSO
dearthropodized arthropods, and therefore are also DEFINITELY NOT
appropriate outgroups to arthropods as a whole. No wonder they continue
to get remipedes in a relatively primitive position. Also no surprise
that chelicerate phylogeny remains unresolved.
There is thus very little new in this new study, and what is new
is questionable. Until they are more creative and test a number of
other possible outgroups to arthropods, they are just going to spin
their wheels and get little in the way new results. They confirmed
Pancrustacea (insects evolved from crustaceans)---big deal. We've known
that for years now. Anyway, I am confident that molecular data is the
main key to answering most questions about deep arthropod phylogeny, but
without being more creative about what outgroups to use, their computers
will continue to spew out very questionable results. It's not the
computers fault---just the humans restricting the results with
questionable assumptions of what taxa are appropriate outgroups. Other
than faulty data (which is probably not a big problem here), nothing is
more damaging to scientific results than false assumptions.
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