[Taxacom] Why stability? - Revisited
Richard Zander
Richard.Zander at mobot.org
Tue May 5 10:37:54 CDT 2015
Taxonomists name new species based on few or one collection by comparing degree of difference from known species. If the new species is sufficiently different that it probably has the traits of a species (whatever concept is current for the group), that justifies the name.
In the past, species were poorly known (as evolutionarily coherent groups of individuals), and such comparison was difficult, hence lots of synonymy. Today, naming a species from one or a few specimens is far more likely to produce a valid taxon.
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Richard H. Zander
Missouri Botanical Garden – 4344 Shaw Blvd. – St. Louis – Missouri – 63110 – USA
richard.zander at mobot.org
Web sites: http://www.mobot.org/plantscience/bfna/bfnamenu.htm and http://www.mobot.org/plantscience/resbot/
-----Original Message-----
From: Taxacom [mailto:taxacom-bounces at mailman.nhm.ku.edu] On Behalf Of JF Mate
Sent: Monday, May 04, 2015 10:23 PM
To: Taxacom
Subject: Re: [Taxacom] Why stability? - Revisited
"Cryptic species are like happiness - you can find them just about anywhere if you are of that frame of mind!...."
"Alternatively, when taxonomists name new species, one of the following circumstances may pertain:
(1) They base the new species on a single specimen, or several essentially identical specimens;
(2) There is a wide range of variability, in which case they need to circumscribe a concept.
Option (1) is very common."
"You don't have to consider that at all for many species. Many original descriptions (even today) are explicitly descriptions of the holotype."
Stephen
we all operate on different species concepts based on our needs, our experience of each group and the state of knowledge of that group. I agree that for the most part biodiversity fits into your first bin but as more information is acquired (specimens, populations, biological information, molecular, karyological...) the species delimitation becomes tighter and they move to bin 2. This often requires splitting species into entities that superficially look the same but which are independent of each other
You may see it as a frame of mind or a desire to overcomplicate things because, for the most part, you only require a typological concept.
This is probably the concept that the general public (as well as many professional users of taxonomic data) need. But reality tends to be more complicated and for those who are ultimately interested in the "natural history" of particular organisms, additional layers of information are necessary.
Jason
On 5 May 2015 at 00:43, Stephen Thorpe <stephen_thorpe at yahoo.co.nz> wrote:
> @Alan: Except that I don't think it is just a function of less taxonomic attention. Many (but by no means all) invertebrates simply can be reliably recognised by matching them up to one (or a just a very few) reference specimens. If anything, problems arise from too much taxonomic attention, whereby taxonomists have to "invent" species in order for it to look like they are really doing anything worthwhile. Cryptic species are like happiness - you can find them just about anywhere if you are of that frame of mind!
>
> Stephen
>
> --------------------------------------------
> On Tue, 5/5/15, Weakley, Alan <weakley at bio.unc.edu> wrote:
>
> Subject: RE: [Taxacom] Why stability? - Revisited
> To: "Stephen Thorpe" <stephen_thorpe at yahoo.co.nz>, "Jim Croft"
> <jim.croft at gmail.com>
> Cc: "TAXACOM" <taxacom at mailman.nhm.ku.edu>
> Received: Tuesday, 5 May, 2015, 10:21 AM
>
> I carefully circumscribed that
> statement as being relative to vascular plants in the Southeastern
> United States. Granted: large parts of the taxonomic world (like
> most invertebrate animal
> groups) are more like the a taxonomic desert I described, where
> types stand large as outposts in the bleak unwatered and minimally
> taxonomist-turbed concept space.
>
> It's in some ways a good place to be. You see something different,
> you name it. Not so much jostling around with inadequately
> conceptualized OTHER taxa, messy old (inadequately typified) names,
> lumping-splitting debates, and the always fun rank (maybe a double
> meaning
> there) opinions.
>
>
> -----Original Message-----
> From: Stephen Thorpe [mailto:stephen_thorpe at yahoo.co.nz]
>
> Sent: Monday, May 04, 2015 5:58 PM
> To: Weakley, Alan; Jim Croft
> Cc: TAXACOM
> Subject: Re: [Taxacom] Why stability? - Revisited
>
> > 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”.
>
> No! Maybe in botany. Not for the majority of species taxa overall
> (which are invertebrate animals). For many (but by no means all) of
> these species, a single specimen is enough to be able to recognise
> them (plus some experience in the group, so that one pays attention
> to likely important diagnostic characters). My identification here
> (http://naturewatch.org.nz/observations/1438142) is a good example. I
> simply compared two images of different specimens, and found them to
> be conspecific with high confidence. I knew nothing of the species
> concerned.
>
> Stephen
>
>
> --------------------------------------------
> On Tue, 5/5/15, Jim Croft <jim.croft at gmail.com>
> wrote:
>
> Subject: Re: [Taxacom] Why stability? - Revisited
> To: "Weakley, Alan" <weakley at bio.unc.edu>
> Cc: "TAXACOM" <taxacom at mailman.nhm.ku.edu>
> Received: Tuesday, 5 May, 2015, 9:45 AM
>
> 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>
> 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] > *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>
> 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]
> 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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> --
> _________________
> Jim Croft ~ jim.croft at gmail.com
> ~ +61-(0)2-62509499 ~ +61 (0)418 675 936 ~ http://about.me/jrc
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