[Taxacom] Reproducibility of descriptive data

Mike Dallwitz m.j.dallwitz at netspeed.com.au
Wed Sep 9 22:39:06 CDT 2009

Mary Barkworth wrote:

"Personally, I prefer to talk about circumscribing a taxon rather than
defining a taxon - it conveys, to me, a recognition that the concept may
change - and the circumscription may need to be changed. Definitions are
less flexible."

I think we mean the same thing. I used the term 'define' (there may be a 
better word) because I was focusing on how taxonomists convey their 
intended circumscriptions to others.

Bob Mesibov wrote:

"you ... have worked hard to move taxonomic description more towards a 
'use this species-determining apparatus and you will accurately ID species 
Y' state."

Better identification is just one of the possibilities when you record 
descriptive data in a suitable database. Leslie Watson and I weren't 
thinking particularly (if at all - I can't remember) of interactive keys 
when we designed DELTA. Here's the abstract from 'Dallwitz, M.J. 1980. A 
general system for coding taxonomic descriptions. Taxon 29: 41–46' 

"A generalized system for the concise representation and manipulation of 
taxonomic descriptions is described. The system is versatile, easy to 
understand, and designed to minimise coding errors. The descriptions can 
replace natural-language descriptions both at the time of recording and in 
publications. The descriptions are also computer-readable, and a program 
is available for translation into natural language and into the formats 
required by some key-generation and numerical-classification programs."

Identification, computerized or not, besides being useful for its own 
sake, is helpful in improving the reproducibility or accuracy of the 
underlying data, as I tried to explain in previous postings. Here's what 
Leslie Watson wrote in 'A Primer for the DELTA System' (supplied with the 

"Use INTKEY extensively — for example, to search for what you know to be 
unlikely or impossible combinations of characters. Obtain natural-language 
translations regularly, and make experimental conventional keys, in order 
to proof-read and search for nonsense. Testing keys is both entertaining, 
and effective in raising questions about the data and uncovering mistakes." *

This is, of course, even more effective if done by people other than the 
author. And, as I suggested in earlier postings, try to iron out as many 
problems as possible _before_ expending a lot of effort on data gathering.

* We seldom bother to make conventional keys now. In the first (1986) 
version of this paragraph, interactive keys are not mentioned. At the 
time, Intkey hadn't been written; we were using a version of Richard 
Pankhurst's ONLINE program, from which Intkey was later derived.

Mike Dallwitz
Contact information: http://delta-intkey.com/contact/dallwitz.htm
DELTA home page: http://delta-intkey.com

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