Re: NANFA-L-- Moribund fish & Life Outside

matt ashton (ashtonmj2003 at yahoo.com)
Mon, 24 Oct 2005 11:10:23 -0700 (PDT)

Gene flow itself seems to confuse me at times as to how much that should be used in criteria for assigning a level of systematics to an organism. There is a classic example from a few text books I have seen of cryptic chars that have 4 very different morphological types, 4 very different life histories and habitats, but COULD reproduce, thus there COULD be gene flow so it is one species. But then look at the number of Lepomis hybrids are out there, and alot of hybridization in Common and Stiped shiners occurs in Ohio.

Then I see myself down in Tennessee where there is alot of isolation that led to alot speciation in the grand scheme over a long period of time, such as the Ulocentras, Doration, alot of the subgenuses and complexes etc.

But now I am working with a fish that was 'historically' though to have inhabited the mainstem TN and lower major tribs, though no evidence exists of this, was described from one river, transplanted to rivers widely seperated by multiple barriers, shows up in an even more widely distributed range after that...So its obviously nearly 100% genetically isolated at every local it occurs in, except maybe two, by multiple dams and dozens upon dozens of river miles....so would the slighest variation in meristics or genetics from two populations suggest independent evolution and warrant subspecies status?

Independently of this, and more on what Dave said in his first paragraph, out of curiousity what is the general amount of time before a change in systematics is accepted, especially in this day in age where information can be spread so easily? My example, and curiousity, comes from a couple papers I have been reading that conclude that Nothonotus should be elevated to genus level. Is this something that might face some resistance because Etheostoma much more 'known' and so widely published about in text and literature? Another example, oddly enough coming from Nothonotus as well, was the split of E. tippecanoe into that and E. denoncourti, which in publication is several years older than my first example and thus seen more in the literature, yet alot of resources that SHOULD be updated haven't.

Matt

dlmcneely at lunet.edu wrote:
Again, if it's not published, it doesn't exist in science. Publication
these days can be in different format (does web publication count for
systematics purposes?) than might be traditional, but it's got to be in
the publically accessible media. I suspect that the systematics folks
are still insisting on print. A thesis is technically published, but
practically, doesn't count, and journals traditionally consider theses
and dissertations as unpublished material (that is, data that appear
there can be published in a journal in the same essential form without
it being considered double dipping as it would if it were published
that way in two different journals).

For organizations that hire people to do research, like universities
and government agencies, publication in peer reviewed journals is
essential to document the research done. A thesis is just a start, in
that context.

So, for the students, listen to your advisors, and publish your stuff.
Otherwise, the rest of us will generally be unaware of it. And Laura
was properly prideful when she mentioned to us that she had published.
Congratulations to you, Laura!

Regarding "subscpecies," I'll go further than Bruce did, beyond saying
it's a "squishy" term. Almost all systematicists nowdays are cladists,
and in cladistic systematics (phylogenetics), the evolutionary species
seems to be the preferred way to define species. That means that an
independently evolving population is a species. If what we used to
call subspecies delineate independently evolving populations (how would
they maintain their integrity otherwise), regardless of whether there
is some gene flow, then those populations are species.

Oh, well, technicalities.

Dave

Dave McNeely

David L. McNeely, Ph.D., Professor of Biology
Langston University; P.O. Box 1500
Langston, OK 73050; email: dlmcneely at lunet.edu
telephone: (405) 466-6025; fax: 405) 466-3307
home page http://www.lunet.edu/mcneely/index.htm

"Where are we going?" "I don't know, are we there yet?"
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