[tdwg-content] Taxon Concept dilemma

Richard Pyle deepreef at bishopmuseum.org
Mon Jul 5 09:36:30 CEST 2010

I think that the basic problem is, as with a taxon "name", there are as many
notions for what is meant by a taxon "concept" as there are people who have
uttered the words.
I think that Peter D. has a good example of what a taxonID might resolve to.
But the question is, which bits of metadata can change under the same
taxonID, and which bits would prompt the generation of a new taxonID?  This
is the fundamental problem I've always had with creating permanent GUIDs for
"taxon concepts" (by anyone's definition, let alone *everyone's*
definition). I've had a similar question concerning ITIS TSNs.  It's still
not entirely clear to me when something generates a new TSN, vs. when
something represents a correction or amendment (e.g., via a comment) to an
existing TSN.
So, for example.  Suppose authority "X" has a well-defined and metadata-rich
taxonID for their concept of "Aus bus".  Later on, they decide that the
species "bus" should be moved to the genus "Xus".  None of the other
metadata (occurence records, diagnostic characters, associated DNA
sequences, etc., etc.) have changed. *Only* the genus placement has changed.
Should Authority "X" brand a new taxonID for this?  In my mind, no.  Because
in my mind, the species concept is defined only by the stuff related to
"bus".  Changing the genus doesn't affect the contents or concept of "bus",
it only changes the concept circumscription for the genus "Xus" (and for
"Aus", if it is retained as a valid genus that no longer includes the
species "bus").
I doubt, however, that there would be universal agreement about this.  


From: tdwg-content-bounces at lists.tdwg.org
[mailto:tdwg-content-bounces at lists.tdwg.org] On Behalf Of Tim Robertson
Sent: Sunday, July 04, 2010 7:09 PM
To: Kevin Richards
Cc: tdwg-content at lists.tdwg.org
Subject: Re: [tdwg-content] Taxon Concept dilemma

Hi Kevin, 

It seems fine to me Kevin, as long as the intention remains the same.  I
would imagine slow changing content behind the object (revisions in higher
names perhaps) and not complete rewrites of the content.

Is there anything inside the Taxon that you can always rely on (something
immutable)?  E.g. a constant ID from the nomenclatural organisation level,
or perhaps some lexcal group ID?  Perhaps you could somehow select one
reference ID from the nomenclatural or concept level as the Taxon ID, and
then you could promote the Taxon as a dynamically assembled object with the
best representation (at request time) for ConceptX.  This is then more
analogous to getTaxonFor(conceptX) than getTaxonById(X).

The alternative to what you are suggesting would presumably be creating new
ID for any change, which seems like it would be difficult to keep anything
in sync, unless I can subscribe to and understand your changes constantly.


On Jul 5, 2010, at 5:43 AM, Kevin Richards wrote:

Hello all,

I have an issue that I would like some comment on.

We have some data that covers Taxa, Names and Concept relationships.
-          A Taxon table that contains the nomenclatural details + accepted
name + parent name
-          Concept + relationship tables that contain details about the name
+ references where the name has been used in a taxonomic sense (ie not
nomenclatural information) - this is specifically a link between the Name
and a Reference
We have fairly permanent Ids for the Taxon Name (nomenclatural) and the
Concepts, but I now what to consider the ID to cover the whole Taxon (ie the
Nomenclatural data + taxon rank + parent name + accepted name, etc, as "we"
understand them).  (Probably equivalent to the taxonID in Dwc)
The problem is this tends to be much more dynamic data - ie, in this
particular case we have aggregated data from a variety of providers and are
in continual revision of this data - as we revise the data the details such
as the accepted name may change - this troubles me a bit, because this could
be seen as fundamentally changing the definition of the object behind the
taxonID.  However, I suspect this is a common case that people find
themselves in - ie revision/tidying of aggregated datasets must be quite
I would prefer to NOT change the taxonID every time we revise that data
(taking the angle that these changes are corrections, so are not changing
the object itself).
Should it be OK to have an object type like this, that is likely to change,
but keep the ID permanent for it - ie accept that some object types are
quite dynamic?
The only other option is to maintain a hideous version audit trail, that
probably hinders the use of the data more than it benefits the end user by
providing "stability".
Any thoughts?


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