[Taxacom] barcode of life

[Doug Yanega]

David Schindel wrote:

>As I feared, Taxacom is now arguing about their claims for what 
>others may have claimed for COI.  Can anyone site a single formal 
>description of a new species based only on COI differences and a 
>standard 2% threshold with no other delimiting features, or is this 
>an imaginary boogyman under the bed?

By getting picky with the details, you avoid the general issue. By 
insisting on a FORMAL description, for example, you avoid the 
implications of published statements like this:

"We DNA-barcoded 2,134 flies belonging to what appeared to be the 16 
most generalist of the reared tachinid morphospecies and encountered 
73 mitochondrial lineages separated by an average of 4% sequence 
divergence. These lineages are supported by collateral ecological 
information and, where tested, by independent nuclear markers (28S 
and ITS1), and we therefore view these lineages as provisional 
species."

This is not the only paper in print discussing "provisional species" 
or "cryptic species" based on COI but not going so far as to try to 
*describe* them. It's a pretty darn subtle distinction between 
*recognizing* new species using COI and *describing* new species 
using COI.

And by insisting that an example be based on COI only, you avoid 
cases like the Leache & Fujita paper discussed here on Taxacom just 
this month, where new gecko species *were* formally described based 
solely on genetics, but using combined mitochondrial and nuclear gene 
trees. The point remains that taxa such as these geckos would, in 
decades past, have been described as subspecies. Similarly, dodging 
the issue by saying "Well, when we go back and look, we can find 
subtle morphological characters that distinguish these taxa" is STILL 
no different from how past taxonomists have defined subspecies (I 
know of very few described subspecies that do not have diagnostic 
morphological characters), so the criticism still stands: the 
differences being seen and described in these studies is functionally 
no different from the differences that in the past were used to 
delimit subspecies, so people have simply redrawn the line as to 
where species start and stop, and that new line is genomic. This 
"redefinition" practice, where what constitutes a species can be 
delimited solely using genetics, is not imaginary.

What I have yet to see, and would very much like TO see, is for a 
barcode proponent to explain the genetic criteria for delimiting 
subspecies. Or am I correct that they simply do not believe in 
subspecies, thereby - by default - leading to the conclusion that all 
genetically diagnosable taxa have to be recognized as species?

Sincerely,
-- 

Doug Yanega        Dept. of Entomology         Entomology Research Museum
Univ. of California, Riverside, CA 92521-0314        skype: dyanega
phone: (951) 827-4315 (standard disclaimer: opinions are mine, not UCR's)
              http://cache.ucr.edu/~heraty/yanega.html
   "There are some enterprises in which a careful disorderliness
         is the true method" - Herman Melville, Moby Dick, Chap. 82