[Taxacom] New lizard species

Sat Jun 5 23:04:16 CDT 2010

Anthony, I wish these new names weren't available, but alas I fear that they are. You are simply trying to interpret the ICZN as you would like it to read, but, unfortunately, it does not forbid even nebulous diagnoses ... it just requires an author to provide some sort of attributes to diagnose the taxon, which they have done in this case. However, there is nothing to compel us to recognise their new species as valid, and we may well decide to treat their (available) names as synonyms ...

Stephen

________________________________
From: Anthony Gill <gill.anthony at gmail.com>
To: Kim van der Linde <kim at kimvdlinde.com>
Cc: TAXACOM <taxacom at mailman.nhm.ku.edu>; Robin Leech <releech at telusplanet.net>
Sent: Sun, 6 June, 2010 3:47:56 PM
Subject: Re: [Taxacom] New lizard species

I see your point Stephen, but I think in the case of node-based identity,
this leads to a circular argument. Don't get me wrong, I do not have a
problem with molecular data being used to diagnose taxa (nor with
"splitting", particularly as a pragmatic exercise in learning more about
species ... or even  biota), but molecular diagnoses should be explicit.
Node-based taxa are self-fulfilling and, because they are analysis
dependent, nebulous.

On Sat, Jun 5, 2010 at 8:19 PM, Kim van der Linde <kim at kimvdlinde.com>wrote:

> That is very well possible. It could be a population on the verge of
> splitting, they might even have developed mating barriers and be real
> cryptic species to be distinguished by bar-coding like two Zaprionus
> species of the same region: Yassin, A., Capy, P., Madi-Ravazzi, L.,
> Ogereau, D. & David, J. R. (2008). DNA barcode discovers two cryptic
> species and two geographical radiations in the invasive drosophilid
> Zaprionus indianus. Molecular Ecology Resources 8, 491-501.
>
> Or it is a solid case of oversplitting that has nothing to do with
> speciation and everything to do with isolated populations, insufficient
> sample sizes etc.
>
> Who knows?
>
> Kim
>
> On 6/5/2010 7:01 PM, Robin Leech wrote:
> > Or, it could be that they just have not looked carefully enough for
> > morphological characters. My suggestion is to give the specimens,
> > several from each DNA group, to a lizard taxonomist.
> > On several occasions I have looked at collections of spiders and at
> > first glance figured that they were all representatives of the same
> > species.
> > but, when I sorted according to locality, then looked again, I did find
> all
> > the morphological characters I needed. I am sure that most morphological
> > taxonomists have had this experience.
> > And I will acknowledge that these lizards might represent a population
> that
> > is on the verge of splitting - has done so with DNA, but has not done so
> > yet
> > with morphology.
> > Robin
> >
> > ----- Original Message ----- From: "Kim van der Linde" <
> kim at kimvdlinde.com>
> > To: "Robin Leech" <releech at telusplanet.net>
> > Cc: "TAXACOM" <taxacom at mailman.nhm.ku.edu>
> > Sent: Saturday, June 05, 2010 2:55 PM
> > Subject: Re: [Taxacom] New lizard species
> >
> >
> >> Yes, that would be a way out of it, but they state explicitly that there
> >> are no morphological or ecological difference. So, we have four lineages
> >> described as species.
> >>
> >> Kim
> >>
> >> On 6/5/2010 4:40 PM, Robin Leech wrote:
> >>> Why don't we take the individuals that have solid DNA differences,
> >>> then when these are sorted, start looking for external morphological
> >>> characters that confirm the DNA?
> >>> Robin
> >>> ----- Original Message -----
> >>> From: "Kim van der Linde"<kim at kimvdlinde.com>
> >>> To: "TAXACOM"<taxacom at mailman.nhm.ku.edu>
> >>> Sent: Saturday, June 05, 2010 12:26 PM
> >>> Subject: Re: [Taxacom] New lizard species
> >>>
> >>>
> >>>> I just read the article, and I have mixed feeling about the article.
> >>>>
> >>>> 1. The central idea is that we can determine species limits by
> >>>> estimating where solid differences in the DNA can be found, as
> >>>> estimated
> >>>> using specific Bayesian methods.
> >>>>
> >>>> 2. The species concept used here is a strict phylogenetic species
> >>>> concept. Whether or not this corresponds with species using the
> >>>> biological species concept is unclear.
> >>>>
> >>>> 3. The number of individuals used for some populations is as low as
> >>>> one.
> >>>> if you have a single outlier. Humm, so much for an estimate of
> >>>> population variance, which is at the heart of the idea.
> >>>>
> >>>> 4. The use of guid trees is problematic at least. Why 4 species, and
> >>>> not
> >>>> 5, 6 or 3. If you a priori start with 4, you of course can find
> >>>> four. As
> >>>> long as you have well-supported nodes with a posterior probability
> >>>> of 1,
> >>>> you can determine species. The fact that the 10-species guide tree
> >>>> provides FIVE species should have resulted in major alarm bells.
> >>>>
> >>>> 5. They use the SAME data to first estimate the species, and then to
> >>>> estimate the probability of those species. This is a circular process.
> >>>> You need two separate data sets to do this. This sounds way to much to
> >>>> self-conformation.
> >>>>
> >>>> Overall, I am not buying this article. Maybe when it is done properly,
> >>>> with sufficient number of individuals per population, independent data
> >>>> sets and a search algorithm that determines what number of species is
> >>>> actually explaining the data the best, I might be persuaded to accept
> >>>> these phylogenetic species, in the context of phylocode.
> >>>>
> >>>> Kim
> >>>>
> >>>>
> >>>> On 6/4/2010 8:19 PM, Bob Mesibov wrote:
> >>>>> If you haven't seen it, do read
> >>>>>
> >>>>> Leache, A.D. and Fujita, M.K. 2010. Bayesian species delimitation in
> >>>>> West African forest geckos (Hemidactylus fasciatus). Proceedings of
> >>>>> the Royal Society B. Published online as doi:10.1098/rspb.2010.0662
> >>>>>
> >>>>> In a well-argued and very clear paper, the authors plump for
> >>>>> probabilistic determination of species, and name four *Linnean*
> >>>>> species on probabilistic grounds. They say '...we are not aware of
> >>>>> any morphological or ecological characteristics that differentiate
> >>>>> these lineages,' and therefore diagnose their species as follows (one
> >>>>> example):
> >>>>>
> >>>>> '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.'
> >>>>>
> >>>>> I don't actually have a problem with the methods used or the
> >>>>> argument. My concern is that the authors confuse Linnean species with
> >>>>> lineages. Lineages can be diagnosed within a probabilistic framework.
> >>>>> They give us an insight into how evolution might possibly have
> >>>>> happened. Linnean species are those nice, easily recognised things
> >>>>> that enable us to retrieve biodiversity information, write field
> >>>>> guides and feel that we have a handle on natural history.
> >>>>>
> >>>>> It's been obvious for a long time that Linnean taxonomy and molecular
> >>>>> taxonomy were headed in different directions, but this paper (IMO) is
> >>>>> a clumsy attempt to yoke them back together.
> >>>>
> >>>> --
> >>>> http://www.kimvdlinde.com
> >>>>
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> >>
> >> --
> >> http://www.kimvdlinde.com
> >>
> >> _______________________________________________
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> --
> http://www.kimvdlinde.com
>
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-- 
Dr Anthony C. Gill
Assistant Director for Collections
International Institute for Species Exploration
School of Life Sciences
PO Box 874501
Arizona State University
Tempe
AZ 85287-4501
USA.

Phone: (480) 965-8620
Fax: (480) 965-6899
E-mail: gill.anthony at gmail.com
http://sols.asu.edu/faculty/agill.htm
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