[Taxacom] Species Definition?

Scott Thomson scott.thomson321 at gmail.com
Tue May 23 10:58:07 CDT 2017


For myself I agree with the notion that as a taxonomist I am trying to
identify populations that do not interbreed (rather than saying
significantly I would say in a way that is deleterious to the species
boundary, most of the time anyway). I admit I approach this from the point
of view of a vertebrate taxonomist which is a bias in my view.

First up with respect to comments on conservation. I do not think that we
can mix conservation priorities into the equation. I have had this issue
put directly in my face. When I described Elseya albagula I had activist
conservation groups literally corner me at a conference yelling at me to
restrict the species to a single drainage (it occurs in 4 drainages) they
wanted to stop a dam being built and wanted to make Elseya albagula a
showcase endangered species to do this. If I were to describe it from a
single drainage this would shoot it up the IUCN rankings permitting
significant conservation value, which in turn could be used to stop the
dam. Supposedly. First up this is a circular argument, ie describe a
species make it restricted in distribution in order to get conservation
value, then use that value to stop a project. That is a circular argument
and will be shredded by any half decent lawyer. Second it was not supported
by the data. They were so admanet about this that several hundred thousand
dollars was spent after I named it to fund a PhD using molecular techniques
to split Elseya albagula, again so they could increase its supposed rarity,
The result of which was demonstrating that I was correct. Waste of money.
All to stop a dam. Please do not misunderstand, I was sympathetic and did
not want the dam either, but the science is the science and I published
what it showed. This is why I do not like mixing taxonomy and conservation
management.

Ok DNA techniques. Using next gen sequencing we are getting 100's thousands
of BP, whole mtDNA genomes etc. I think there are three things this is
doing to taxonomy that is negative. First up it is one of the causes of the
defunding of morphological taxonomy and museums. Second I think many of the
DNA researchers are probably confusing pedagrees with phylogenies at this
point. I am saying that harshly and overstating it to make the point. But
they are way below the species level, probably at times below the
subspecies level. However like all workers dealing with phylogenies naming
taxa in papers is a measure of their work. So they are applying binomials
to populations that show little to no real difference, cannot be
distinguished morphologically, are known to be capable of interbreeding.
The entire radiation of the Galapagos Tortoises, currently all considered
species have less genetic diversity than our species does. So should they
be species? subspecies? forms? I have heard their excuse for this,
apparently humans are an exception and these molecular techniques do not
apply to us. Yes that has been said. Lastly it is causing a chasm between
paleontology and taxonomy, that should not exist. These workers are using
paleontological works without reference, understanding, phylogenetic backup
to date their molecular trees. They look them up on fossilworks, shove them
into their analysis and run BEAST.  The results are like WOW. You have to
be kidding. Three papers in a 2 year period dated the family Chelidae at
57M, 35M and 22M for the entire radiation. Yet I have three fossil chelids
from modern genera that are over 100M so how does that make sense.

I think molecular tools are significant and important tools in
phylogenetics, but it must stay in touch with morphology and through this
the fossil record. It needs to look at its models and figure out what they
are distinguishing.

Cheers, Scott

On Tue, May 23, 2017 at 6:35 AM, Richard Pyle <deepreef at bishopmuseum.org>
wrote:

> ....hence my qualification of "most" taxonomic communities.
>
>
> > -----Original Message-----
> > From: Stephen Thorpe [mailto:stephen_thorpe at yahoo.co.nz]
> > Sent: Monday, May 22, 2017 10:58 PM
> > To: taxacom at mailman.nhm.ku.edu; deepreef at bishopmuseum.org
> > Subject: RE: [Taxacom] Species Definition?
> >
> > Asexual lineages pose a problem to this simple concept, however!
> >
> > --------------------------------------------
> > On Tue, 23/5/17, Richard Pyle <deepreef at bishopmuseum.org> wrote:
> >
> >  Subject: RE: [Taxacom] Species Definition?
> >  To: "'Stephen Thorpe'" <stephen_thorpe at yahoo.co.nz>,
> > taxacom at mailman.nhm.ku.edu
> >  Received: Tuesday, 23 May, 2017, 6:31 PM
> >
> >  > I still go along with
> >  species are populations which
> >  > do not
> >  freely interbreed (to a significant extent) under natural  conditions.
> >
> >  Yup.  I
> >  reckon that most taxonomic communities use something along  these lines
> as
> > the center-of-mass for what they,  collectively, use to say what a
> species is.
> >
> >  Aloha,
> >  Rich
> >
> >
>
>
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> Nurturing Nuance while Assaulting Ambiguity for 30 Years, 1987-2017.
>



-- 
Scott Thomson
Museu de Zoologia da Universidade de São Paulo
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