[Taxacom] New lizard species

Sun Jun 6 05:42:23 CDT 2010

This disagreement hinges on confusion between different meanings of the word "character".

Its (original) common meaning (which is more-or-less reflected in the ICZN definition) as a particular characteristic by which something can be recognised/differentiated (an attribute of a particular thing, e.g. brown eyes) became confused when computer analyses came along and a term was needed for each base feature which shows such character variations (e.g. eye colour). English did not have a word for this concept, so the word "character" (with a subtly changed meaning) was coopted for the purpose, and "character state" was used for what had generally been called a "character" or "attribute". Stephen seems to be interpreting the Code meaning of "character" as that which varies, rather than an individual attribute or "character state". A bit more thought would show that the intention of the Code must be the citation of particular features (attributes = character states) by which a taxon can be recognised and differentiated from other(s) - e.g. "has red rather than brown eyes", not "differs in eye colour" (without specifying how it differs). Even if one were to consider that a description without comparison to other taxa would suffice (a somewhat moot point), a description along the lines "This species is characterised by eye colour, tail length ..." would seem to satisfy Stephen's concept, but cannot be the sort of thing envisaged for Code compliance because it is completely useless.

>From the sample diagnosis in the lizard paper (I don't have access to the full paper, unfortunately): 'Diagnosis. This species includes all populations that cluster with those from the southern portion of the Congolian rainforest included in this study (southern Cameroon, Gabon and Congo), with strong support in the Bayesian species delimitation model', this is even less informative since it does not specify any differences at all, but merely indicates a vague hypothetical grouping. It cannot by any stretch of the imagination be considered to state "in words characters [=particular attributes] that are purported to differentiate the taxon".

Denis

>>> Stephen Thorpe <stephen_thorpe at yahoo.co.nz> 2010/06/06 04:36 am >>>
depends what you mean by "characters" 

ICZN glossary:

character, n. 
Any attribute of organisms used for recognizing, differentiating, or classifying taxa. 

I think "any attribute" is sufficiently general???

Stephen

________________________________
From: Anthony Gill <gill.anthony at gmail.com>
To: Stephen Thorpe <stephen_thorpe at yahoo.co.nz>
Cc: fwelter at gwdg.de; taxacom at mailman.nhm.ku.edu 
Sent: Sun, 6 June, 2010 1:06:21 PM
Subject: Re: [Taxacom] New lizard species

I fail to see how a node-based definition includes characters. If there are characters that support the Bayesian relationships, these are the ones that must be identified in the diagnosis. As it stands, I do not think the diagnosis satisfies the Code.

On Sat, Jun 5, 2010 at 5:48 PM, Stephen Thorpe <stephen_thorpe at yahoo.co.nz> wrote:

unfortunately, I must disagree that the new species descriptions fail to comply to Article 13.1.1.
>
>
>Article 13.1.1 "be accompanied by a description or definition that states in words characters that are purported to differentiate the taxon"
>
>'Diagnosis. This species includes all populations that cluster with those from the southern portion of the Congolian rainforest included in this study (southern Cameroon, Gabon and Congo), with strong support in the Bayesian species delimitation model'
> 
>Francisco say: It would be equivalent to a statement "colour differs from species B", without announcing how it would differ. It makes no difference if a computer tells me under 99.999 % likelyhood that the colour differs
> 
>Article 13.1.1 does not explicitly rule out relative characters, so you could say something like "Diagnosis: 5mm larger on average than the other species", and that would be OK. The article also only explicitly requires you to specify the characters, and not how they differ. So you could just say "differs in size, shape, colour, texture, ..."
> 
>If the article is intended to be more restrictive, then this needs to be made explicit ...
> 
>Stephen
>
>
>________________________________
>From: Francisco Welter-Schultes <fwelter at gwdg.de>
>To: fwelter at gwdg.de; Heath Blackmon <coleoguy at gmail.com>
>Cc: taxacom at mailman.nhm.ku.edu 
>Sent: Sun, 6 June, 2010 5:53:48 AM
>
>Subject: Re: [Taxacom] New lizard species
>
>
>> couldn't the fact that when analyzed these populations sort in
>> a certain way be considered a trait and thus satisfy the
>> requirements of 13.1.1?
>
>No it cannot, this is the point. It would be equivalent to a
>statement "colour differs from species B", without announcing how it
>would differ. It makes no difference if a computer tells me under
>99.999 % likelyhood that the colour differs.
>
>Francisco
>
>
>University of Goettingen, Germany
>www.animalbase.org 
>
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-- 
Dr Anthony C. Gill
Assistant Director for Collections
International Institute for Species Exploration
School of Life Sciences
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