It depends on what you mean by "different taxa".  If you are using the word
"taxa" here to imply "species or lower ranks", than I don't think it would
solve the problem.  But if you mean it in a generic way, then I'm OK with
that.  By "in a generic way", suppose I had a trawl sample or a plankton tow
sample that included unidentified organisms from multiple phyla, all of
which are animals.  I should not be prevented from representing this
aggregate as an "Individual", with an identification instances linked to a
taxon concept labelled as "Animalia".  This means the contents of the
Individual all belong to a single taxon (Animalia), and therefore it does
not violate the condition excluding aggregates of different taxa. An
This is the circumstance where I would call it an "aggregation" (or whatever term) and not an Individual.  
instance of Individual so identified would be almost useless for many
purposes, I agree -- but it's easy enough to filter such Individuals out by
looking at dwc:taxonRank of the Taxon to which the Individual was
That's not true.  Look at this:
http://bioimages.vanderbilt.edu/ind-baskauf/04101
Here is an image from an individual that I know is an Metrosideros species. I have identified it to genus but an Metrosideros expert could probably identify it to species at a later time.  Your mechanism of looking at the taxon rank would not allow such Individuals to be separated from an "aggregation" that consisted of biological individuals belonging to two different species of Metrosideros.  Click on the "Metrosideros [unknown]" link at the top of the page.  You now see all of the images I have for Individuals that are in the Metrosideros genus.  They are grouped by Individual by the locally unique identifiers under the images.  The use case for which I want dwc:Individuals is to keep the images from the same individual (or a specimen and an image, or two specimens) grouped together.  If I later were able to determine that the various Individuals on that page to species, I would assign them to a more specific taxon and that identification would automatically be applied to all images (or images and specimens or whatever) that I have grouped under a single Individual identifier.  Another example is:
http://bioimages.vanderbilt.edu/ind-baskauf/70858
I know its some kind of dicot and therefore have identified it to class Magnoliopsida.  When I can identify it to species, I'll apply a more precise identification to that individual.  That is different than calling some flower garden containing a bunch of dicots an "Individual" which would have a taxon rank of class.  I feel strongly that kind of thing should be called something different (i.e aggregation or something).

I really feel like "watering down" the meaning of Individual in the way that you are suggesting (allowing it to be an aggregation of species or whatever you want to call them) is going to defeat the whole purpose of why I suggested having the class in the first case.  So if somebody can think of an inoffensive way to describe a terminal taxon or species (or ssp. or var. if it exists), that is really what I intend for Individual to be restricted to.  I'm not proposing the "aggregation" view.

Steve
identified. Also, it's not useless for all purposes, because a botanist
would like to know that s/he doesn't have to look through that sample to
find stuff of interest.

I guess my point is, there should not be any rank-based requirement for the
implied taxon circumscription of an "Individual".

Rich


    


<><><><><><><><><><><><><><><><><><><><><><><><>
Nico Cellinese, Ph.D.
Assistant Curator, Herbarium & Informatics
Adjunct Assistant Professor, Department of Biology

Florida Museum of Natural History
University of Florida
354 Dickinson Hall, PO Box 117800
Gainesville, FL 32611-7800, U.S.A.
Tel. 352-273-1979
Fax 352-846-1861
http://cellinese.blogspot.com/



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Vanderbilt University Dept. of Biological Sciences

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