[Taxacom] Call for Comments: Taxonomic Practice and the Code

Stephen Thorpe stephen_thorpe at yahoo.co.nz
Sat Jan 11 22:10:10 CST 2014


Alan,
I'm not sure that I was being sufficiently clear? My point was that, sure, for some well-studied species, you can talk about the "species concept" in a well-defined way. But, for the vast majority of species, the "species concept" hasn't changed since the original description (which is why the two things are typically equivalent). For gener, though, the situation is very different, and yet the taxonomic literature makes little or no reference to older generic concepts, becuase they aren't relevant to anything much. It is also fairly rare overall to have two or more competing contemporary concepts for the same genus. When that does happen, taxonomists just make some reference to whose concept they are following. Now, we appear to be entering an age of data aggregation. Going back to species, if the species concept has changed over time, then this is going to cause complications, but, assuming that there is only one currently accepted species concept for a
 given species, historical data based on past concepts is effectively misidentified in cases which don't agree with the modern cocept, and should be treated accordingly. But, as I said, for the vast majority of species (tiny arthropods, etc.), there is no problem because the "species concept" hasn't changed since the original description. Caveat: In a sense, most species concepts have changed, because many old species are now split into previously unrecognised species, but you can't specify any well-defined "concept" to track that sort of change. One just has to be very, very careful about historical data ..
Cheers,
Stephen


________________________________
From: "Weakley, Alan" <weakley at bio.unc.edu>
To: Stephen Thorpe <stephen_thorpe at yahoo.co.nz>; Paul van Rijckevorsel <dipteryx at freeler.nl>; "taxacom at mailman.nhm.ku.edu" <taxacom at mailman.nhm.ku.edu> 
Sent: Sunday, 12 January 2014 4:50 PM
Subject: RE: [Taxacom] Call for Comments: Taxonomic Practice and the Code


Stephen Thorpe:  Nico Franz has already responded about this from a partially different angle, but...  you state that 'The "concepts" you speak of are equivalent to the original descriptions'.  But, "taxonomic concepts" have very little to do with original descriptions in most cases -- that's just the problem and why an explicit approach to taxonomic concepts is so urgently needed.  A name, a description, and a holotype put a flag in the 3-D taxonomic landscape.  There are other flags in that landscape.  What are the actual lines between (borders of) the taxonomic entities?  In the alpha stage of taxonomy, very little attention was put to this; in later stages somewhat more, at least for "well-studied" groups, but still very imperfectly.  We will always have differences of taxonomic opinion:  when monographer X, monographer V, taxonomist Y, and country checklist Z differ, how do the specimens (their locations, their morphologies, their DNA
 sequences) sort out relative to the names?

Vascular plants may be considered a "well-studied group" overall, though we sure have a very imperfect knowledge of the taxonomic reality in a very large majority of genera!  But, just to make the point explicit, an example:  Andropogon virginicus Linnaeus.  In treatments of the last 30 years, where entities in the complex described as species, subspecies, varieties or informal "variants" are A, B, C, D, E, F, G, H, I, J, and K, in any given flora, or species list, or biodiversity database, "Andropogon virginicus Linnaeus" can mean A, or ABCDE, or ABDE, or ABCDEFGHIJK, or ABCDEFG.  The only necessary meaning is that the finest level entity that includes the type ("A") is "Andropogon virginicus Linnaeus".  Without explicit concept mapping, any given specimen, any given name on a species list, and any name in an ecological sample -- is seriously ambiguous, because it can mean A, or B, or C, or ABCD, or ABDE, or ABCDEFGHIJK, or ...  Therefore, any
 aggregation of data based simply on that *name* is at best flawed, and at worst highly misleading or essentially meaningless.  The very recent and excellent Catalogue of Seed Plants of the West Indies (Acevedo-Rodriguez and Strong 2012) says that "Andropogon virginicus Linnaeus" is "native to Bahamas, Cuba, Hispaniola, Jamaica, Puerto Rico, Tobago, Trinidad, United States, Mexico, Central America, and South America (Colombia)".  Finer scale databases place "Andropogon virginicus Linnaeus", even when they recognize many entities as separate from it, in many locations where I know it does not occur (these ascriptions falsely based on other taxa at one time and by various taxonomists included within "Andropogon virginicus Linnaeus".  Knowing that a good dozen of other entities are now recognized at specific or varietal rank as different than A. virginicus sensu strictissimo, what information can I take from this range statement? -- very little.  I may
 take comfort that some of these entities are listed separately and assigned separate (but largely overlapping) ranges.  But how sure can I be that when the segregate taxa are listed, there distributions have been carefully segregated as well? -- not very.

So, this is also related to data aggregation, its usefulness, and the various aggregators.  Having "concept-mapped" the recent (last 80 years) usage of names in the vascular plant flora of the Southeastern United States (over 7000 currently accepted taxa, and many times that many names) I can say that a large percentage of names ("Genus species author") are seriously ambiguous.  Without that being fixed, nearly all scientific and practical applications of taxonomic information are seriously compromised.  In the US, and for vascular plants and vertebrate animals (at least, and for now), NatureServe (the primary and functional biodiversity database for North America) takes this issue seriously and endeavors to deal with it.  Mechanical aggregators (essentially by definition) do not and cannot.

Alan

Alan Weakley
Director and Curator, UNC Herbarium (NCU), North Carolina Botanical Garden
Adjunct Assistant Professor, Dept. of Biology and Curriculum in Ecology and the Environment
Campus Box 3280, Coker Hall 419
University of North Carolina at Chapel Hill
Chapel Hill NC 27599-3280
919.619.1101 (mobile)


-----Original Message-----
From: taxacom-bounces at mailman.nhm.ku.edu [mailto:taxacom-bounces at mailman.nhm.ku.edu] On Behalf Of Stephen Thorpe
Sent: Thursday, January 09, 2014 4:15 PM
To: Paul van Rijckevorsel; taxacom at mailman.nhm.ku.edu
Subject: Re: [Taxacom] Call for Comments: Taxonomic Practice and the Code

Paul:
I still say that the primary function is, and has always been, to link the name to the original publication (types are a secondary issue, that I clearly ought not to have thrown in!). Sure there were author citations before there were types, but the same cannot be said for original publications. The "concepts" you speak of are equivalent to the original descriptions. There appears to be much confusion today over so-called "taxonomic concepts" ...
Cheers,
Stephen
 

________________________________
From: Paul van Rijckevorsel <dipteryx at freeler.nl>
To: taxacom at mailman.nhm.ku.edu 
Sent: Thursday, 9 January 2014 9:56 PM
Subject: Re: [Taxacom] Call for Comments: Taxonomic Practice and the Code


From: "Stephen Thorpe" <stephen_thorpe at yahoo.co.nz>
Sent: Wednesday, January 08, 2014 9:20 PM

> The primary function of author/date of taxonomic names 
> is [...] to link the name to an original publication and 
> primary type, and also to set priority for synonymy. 

***
This may be the primary use Stephen Thorpe puts author
citations to, but author citations existed long before there
were types. The classic use of author citations was to
give credit and to refer to other people's concepts. In no 
Code is there anything about using author citations to
link to primary types ...

However, if authors are going to be cited, it is very
useful to include a date, indeed to help determine
priority.
* * *

From: "Stephen Thorpe" <stephen_thorpe at yahoo.co.nz>
Sent: Thursday, January 09, 2014 12:36 AM

> Well, such an interpretation may, for all I know, be 
> standard in botany, but for zoology the interpretation 
> of "sensu" is more variable. I didn't say that it means 
> misidentified. I meant that it implies misidentification ...

***
Actually the zoological Code is explicit. The first Example in
Art. 51 says:

    [...] Cancer pagurus Linnaeus as used by Latreille may be 
    cited as "Cancer pagurus Linnaeus sensu Latreille", [...]

nothing about implying misidentification, just normal common
sense ...

Paul 

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