[Taxacom] Why stability? - Revisited

[Weakley, Alan]

Jim – we are also in “furious agreement” on that.

From: Jim Croft [mailto:jim.croft at gmail.com]
Sent: Monday, May 04, 2015 5:45 PM
To: Weakley, Alan
Cc: TAXACOM; Paul van Rijckevorsel
Subject: Re: [Taxacom] Why stability? - Revisited

We are obviously in furious agreement. :)

It wasn't the 'flag in the sand' that caught my attention, but the 'around which a taxon is defined' bit.  It is usually the other way - a taxon is defined and a type is selected, either from existing, or newly designated if none exists.

But we do seem to have a slight difference in approach, and it may be simply semantic. "a very small percentage of taxa are unambiguously circumscribed based on their type alone" - I don't circumscribe taxa based on types as such. For the purposes of taxonomy, the type is just another specimen, even if it is the only specimen. When the taxa are sorted, then the type becomes important. I like to draw very clear distinctions between the acts of taxonomy and nomenclature, and between the type specimen as a specimen and the type specimen as a type. ;)

jim

On Tue, May 5, 2015 at 6:58 AM, Weakley, Alan <weakley at bio.unc.edu<mailto:weakley at bio.unc.edu>> wrote:
I agree completely with what you say, Jim, and was making the same point you ae making – so, am not sure what you are objecting to in my “flag in the sand” analogy.  The flag might be over on one extreme edge of the “taxonspace” (as implied by Paul).  A type anchors a name but does not circumscribe it (except in the narrowest possible sense of the type itself).

In very poorly understood groups (with a high taxon:systematist ratio) the types stand large as outposts in the bleak unwatered and minimally taxonomist-turbed desert.  This seems to be what Stephen was describing in his universe.  As systematics proceeds, the types are still critical to anchor the application of names, but the emphasis shifts to the boundaries between the various flags (types), and which flags are taken over by others and become synonyms of what is regarded as a “good” taxon (not to sound too militaristic).  In the vascular flora of the Southeastern United States, 7200 taxa currently recognized, a very small percentage of taxa are unambiguously circumscribed based on their type alone.  Put another way, the great majority of taxa can only be unambiguously circumscribed by something beyond the name (as typified) because there are sensu stricto or sense lato interpretations “in play”.  If I write “Andropogon virginicus Linnaeus 1753” on a specimen (or a record in a database) without sec or sensu, no one tell whether I mean it in the narrowest sense, or variously including 1, 3, 7, or 12 other taxa recognized in “lumpier” taxonomic schemes currently or in recent decades followed by other credible taxonomic experts.

From: Jim Croft [mailto:jim.croft at gmail.com<mailto:jim.croft at gmail.com>]
Sent: Monday, May 04, 2015 4:36 PM
To: Weakley, Alan
Cc: TAXACOM; Paul van Rijckevorsel

Subject: Re: [Taxacom] Why stability? - Revisited


This is not strictly true. The purpose of the type is to anchor the name, as Paul describes. It is not to centre, circumscribe or in any way define the taxon. That is a separate process that may end up including one or more types, and hence one or more names. At least with plants. People may think they are defining a taxon by selecting the 'best' possible type to represent their concept, and it is probably a wise thing to do, but this is not what is happening according to the Code. They are simply anchoring the name.

Jim
On 05/05/2015 5:20 AM, "Weakley, Alan" <weakley at bio.unc.edu<mailto:weakley at bio.unc.edu>> wrote:
The type is a flag in space around which the circumscription of a taxon (its concept) is defined -- usually in relation to other, "competing" taxa.

-----Original Message-----
From: Taxacom [mailto:taxacom-bounces at mailman.nhm.ku.edu<mailto:taxacom-bounces at mailman.nhm.ku.edu>] On Behalf Of Paul van Rijckevorsel
Sent: Monday, May 04, 2015 7:57 AM
To: TAXACOM
Subject: Re: [Taxacom] Why stability? - Revisited

I was a little uneasy why Stephen Thorpe's attitude that taxa are defined by types is so alien to me.

But it is very straightforward: from the very first the 'botanical' Code has laid down that nomenclatural types are not necessarily the most typical or representative element of a taxon (that is, holding only the type, it is not possible to predict with any degree of confidence what the taxon exactly looks
like: the type is only the type) .

For plants there does exist a situation where the whole unit is determined by a reference specimen, namely in the ICNCP (Cultivated-plant-Code), resulting in names of the type Hydrangea macrophylla 'La France'.

The ICNCP deals with a field of considerable complexity (and which does benefit from regulation), but taxonomy is not involved.

Paul
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