[Taxacom] describing species based on DNA sequences alone

Richard Zander Richard.Zander at mobot.org
Mon Jan 16 11:59:06 CST 2017

Scott's point is well made. Just finding a trait or two that corresponds to a molecular difference does not corroborate anything. True corroboration requires the apposite morphological entity to stand on its own. 

Molecular data can be really really certain that a molecular thing did not occur by chance alone, but what is the thing? Could it be a molecular race in some isolation, but insufficiently pressured into a new evolutionary role with accompanying morphological differences?

Molecular species concepts with algorithms that depend on the biological species concept to work are piffle. 

What happened to evolution-based taxonomy? Should DNA tracking traits be treated as genetic differences? There is a cognitive dissonance operating here, I think, that equates DNA differences with genetic differences whereas the latter include only those differences that affect expressed traits.

Richard H. Zander
Missouri Botanical Garden – 4344 Shaw Blvd. – St. Louis – Missouri – 63110 – USA
richard.zander at mobot.org 
Web sites: http://www.mobot.org/plantscience/bfna/bfnamenu.htm and http://www.mobot.org/plantscience/resbot/ 

-----Original Message-----
From: Taxacom [mailto:taxacom-bounces at mailman.nhm.ku.edu] On Behalf Of Scott Thomson
Sent: Monday, January 16, 2017 7:34 AM
To: Elena Kupriyanova
Cc: taxacom at mailman.nhm.ku.edu
Subject: Re: [Taxacom] describing species based on DNA sequences alone

Personally I am against the naming of species without a morphological analysis including a differential diagnosis, preferably one that actually works.


I see plenty of recent descriptions where it is obvious that the description is based on a molecular only study. They have a morphological differential diagnosis because with many vertebrates its unlikely a name will be accepted without one, however, this morphological diagnosis is based only on poor quality characters they get from literature review that the authors clearly do not understand. The diagnosis also clearly does not work, of course in nomenclature it does not have to work, just has to be there. ie "purports to diagnose the taxon". But if you actually look at those taxa the diagnostic characters, that do work, are there.

Cheers, Scott

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