Circumscription equivalencies

Richard Pyle deepreef at BISHOPMUSEUM.ORG
Wed Oct 17 02:07:23 CDT 2001

I wrote:

> The issue you raise has to do with mapping equivalencies among assertions;
> that is, whether:
> "Genus species Smith 1999, sensu Jones 2001"
> is equivalent to:
> "Genus species Smith 1999, sensu Pyle 2000"
> ....or, alternatively, whether Pyle and Jones had different
> concepts of what
> the biological scope of kin to the primary type of "Genus species Smith
> 1999" is.

While this is a good example of mapping circumscription equivalencies, a
more typical example is along the lines of whether:

"GenusA speciesX Smith 1999, sensu Jones 2001"

is equivalent to:

"GenusB speciesY Randall 1967, sensu Pyle 2000"

In other words, often the task is mapping equivalencies between
taxon-concepts tied to different names, rather than distinguishing different
taxon-concepts tied to the same name....but both sorts exist and need to be
dealt with.

I think this whole issue of mapping circumscription equivalencies and
distinctions is a stimulating one, worthy of its own thread (hence the new
subject line).  It occured to me just now that a lot of the miscommunication
in discussions such as these stem from how we each approach the problem.
Folks like me approach the problem in a "bottom-up" way; that is to say,
we're interested in dissecting the "first principles" of the information,
and codifying it in a model that reflects the nature of the information
itself -- a largely conceptual framework.  Another approach is a much more
practical framework, recognizing a real-world need to compare (to follow
along the lines of Dr. Pullan's example) a flora survey of an area done in
1985, to a flora survey done in the same area in 1997.  The prevailing
taxonomy no-doubt would have changed during the time between the surveys, so
to get biologically meaningful comparisons between the two, it is important
to map the taxonomic equivalencies.  I see this more as a "top-down"

What I think (hope) I'm seeing is that these two quite disparate approaches
may be meeting somewhere in the middle (in the vicinity of "assertions"). On
the one hand, this might be "old news" to the folks who have spent many
years contemplating the issues.  On the other hand, based on some of the
public and private posts I've received, there is still much progress to be
made simply by establishing the fundamental concepts -- making sure that
we're all speaking the same language.

O.K., it's time for bed....


Richard L. Pyle
Ichthyology, Bishop Museum
1525 Bernice St., Honolulu, HI 96817
Ph: (808)848-4115, Fax: (808)847-8252
email: deepreef at
"The views expressed are the author's, and not necessarily those of Bishop

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