[Taxacom] Morphological characters was New lizard species
dyanega at ucr.edu
Tue Jun 8 18:59:39 CDT 2010
Jason Mate wrote:
>Dear Fred, your argument assumes that only morphological differences
>can define species; alas there are numerous examples that prove this
>argument fallacious. Off the top of my head, the A. gambiae complex.
>I cannot defend nor criticize the paper that spurred the whole
>argument in the first place since I don´t have access to a copy but
>even assuming that it is truly "rubbish", one example doesn´t set a
>rule. In the end molecular data will become part of the tool-kit of
>taxonomists. That doesn´t mean that I endorse Phylocode. However
>their strengths lie precisely in the Code´s weaknesses and this
>thread is a good example that maybe some changes might be necessary
>to accomodate the shifting reality "out there". Since we have
>several commisioners following this thread they could suggest
I'm not sure that there is anything needed here in the way of
suggestions, as this is a false dichotomy. Let me illustrate my point:
Consider the following possible diagnoses:
(1) Taxon X is diagnosable by its possession of "AT" in the 16th &
17th codon positions of the "eyeless" gene, where all known congeners
possess "CC" or "CG" at these positions.
(2) Taxon X is genetically different from taxon Y.
Example #1, while purely molecular in nature, is a perfectly
code-compliant diagnosis, and - other things being equal - would
suffice to make a taxon name available. Example #2 is NOT a
code-compliant diagnosis, and is precisely analogous to the present
example. Significantly, example #2 is not unavailable because it is
based on molecular data, but because it does not state in words what
the "diagnostic molecules" actually ARE. Stephen seems to be of the
belief that the present case is simply a matter of how ones defines a
"character", and it is not *just* about that. The Code Article in
question reads "accompanied by a description or definition that
STATES in words..." - and I emphasize the word "states" here because
that is where the primary failure here lies. The purportedly
diagnostic characters HAVE NOT BEEN STATED in the description.
Note that neither example lives or dies on the basis of the perceived
validity of the taxonomy, which is purely subjective; this is
strictly a matter of whether the description complies with the
nomenclatural rules, and example #2 fails the test for exactly the
same reason the lizard descriptions fail. Other diagnoses which would
fail would be things like:
(3) Taxon X is diagnosable by being all individuals below node Y in
(4) Taxon X is diagnosable by its being the sister to taxon Y in our analysis.
(5) Taxon X is diagnosable by being called "purumbe" by the local
villagers, while taxon Y is referred to as "sasambe".
(6) Taxon X is diagnosable by virtue of my liking this species, while
I dislike its congeners.
A dedicated pedant might insist that these are "attributes of
organisms" and therefore "characters", but they are not. A position
on a cladogram is NOT a character, nor is the name given to an
organism, nor one's opinions about an organism. They are all purely
Doug Yanega Dept. of Entomology Entomology Research Museum
Univ. of California, Riverside, CA 92521-0314 skype: dyanega
phone: (951) 827-4315 (standard disclaimer: opinions are mine, not UCR's)
"There are some enterprises in which a careful disorderliness
is the true method" - Herman Melville, Moby Dick, Chap. 82
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