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Re: [diatom_forum] Gomphonema truncatum

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  • Richard Carter
    Charles, I can make a few recommendations as to your diatom images -- but do take them with at least an ounce of salt!  And I think sub-fossil better fits
    Message 1 of 38 , Apr 28, 2012
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      I can make a few recommendations as to your diatom images -- but do take them with at least an ounce of salt!  And I think "sub-fossil" better fits the Toome Bridge deposit, as it is quite recent.

      The centrics on Image 2 are interesting.  To the top left is what I have been calling Stephanodiscus rotula (Kützing) Hendey, an ID made when I accepted the then-current synonymy with S. astraea.  Now that they are once again both believed to be good species, I have no idea what to call it -- no access to the publication, as usual.  R. Firth also listed S. neoastraea Håkansson & Hickel from Toome Bridge, so that's worth looking for.  I've not seen one.  I don't recognize the taxon at the top.  The one at the right looks like a Cyclotella, and the one at the bottom is a Puncticulata.

      Image 3 is Cymatopleura elliptica var. hibernica (W. Smith) Van Heurck, very abundant.  The nominate variety occurs rarely in some Toome Bridge samples.

      On Image 9, the middle specimen is Neidium productum (W. Smith) Cleve.  To identify the others would require measurements of striae density.  (I think they are probably the same species.)

      On Image 10, the one next to the bottom shows the characteristic swollen ends and granulation of the axial area of Pinnularia acrosphaeria W. Smith.

      Image 14 looks like two specimens of Epithemia turgida var. westermannii (Ehrenberg) Grunow.  Very similar to E. hyndmanii W. Smith, but with the ends a bit less rounded.

      That's about all I can say, for what little it's worth.................  Very nice photographs, I can say that for sure!



      From: charles suslavage <suslavage@...>
      To: diatom_forum@yahoogroups.com
      Sent: Thursday, April 26, 2012 9:47 PM
      Subject: Re: [diatom_forum] Gomphonema truncatum

      Hi Dick,
      I understood your thesis and its intent and as always it was interesting and informative. My confusion came from reviewing what source material is available to me after reading your post. In particular the CAS data base and the list of synonyms for a given entry get real confusing when you begin to cross reference searches within their database.
      I agree that the task of keeping up with all the changes in the discipline is daunting and impossible for the amateur. I also have come to believe that it is not essential for the amateur to be at the cutting edge only well informed.  We amateurs should strive to be as accurate as is possible given our resources.
      For my part I am happy when I get the genus correct happier still if I get genus and species correct and delirious when I identify genus, species, and variety. None of this was or is possible without your encouragement and guidance.
      While I am on my soap box I should say that to study micropaleontology, fossil diatoms a major component, one needs to study the living organisms in order to understand the fossils.
      If your getting back to micropaleontology on Laszek’s web site diatomaceae.com I have started a folder of diatoms from Toome Bridge that I would like you to take a look at and if possible make recommendations.

    • Richard Carter
      Rob, A very stimulating post!  I think your list of questions is excellent -- I m sure each of us would offer different answers, but I also think that we
      Message 38 of 38 , May 2, 2012
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        A very stimulating post!  I think your list of "questions" is excellent -- I'm sure each of us would offer different answers, but I also think that we each need to consider such questions.

        Thanks much,


        From: Rob Kimmich <kimmich46@...>
        To: diatom_forum@yahoogroups.com
        Sent: Wednesday, May 2, 2012 12:10 PM
        Subject: [diatom_forum] Diatom Directions


        Your note adds a lot to this great discussion of amateur study of diatoms. I have had your experience of using the SEM images to explain what I see with the LM. Dick has been one of my main sources for learning, too.

        I see this discussion as what to do about distinguishing species, if that is possible for anyone, even with an SEM and a molecular lab. Even Dick, with the university library in Phoenix, is challenged, as he says. From my seat, the naming discussions have been cordial so far, e.g., Charles asking Dick to clarify a name as far as possible and Dick replying with a careful answer.

        I certainly share the frustration I think I hear from Dick about pinning down an identification. I am finding that taking on any of this demands an acceptance of just not being able to know. Your point about not caring about naming accuracy may be the way to go here.

        Hearing from you, Dick, and Dave helps me try to figure out what direction I want to take with all the images that I am accumulating and what it is I want to learn. Do I want to make species (or genus) lists of collections made? Am I happy with naming to genus? Do I want to learn more ecology? How important is sharing what I learn? (This forum has been a good place for that so far.) Do I want to continue developing LM technique?

        By the way, would you be willing to ID some extant Mastogloia from the California desert?

        Best regards,

        On Wed, May 2, 2012 at 9:08 AM, klaus.kemp <klaus.kemp@...> wrote:
        Due to a catastrophic meltdown of my hard drive on my laptop I have been kept out of the loop for some time, only to find that where evryone behaved and everyone gained something from the group I now find there are ripples of dissent] and over what NAMES!
         May I remind you all that when I first joined the group I quoted my dear friend Bernard Hartley who on our first meeting said " We must/ should never fall out over a name". Now I find that there is dissent over naming of Diatoms, those of you old enough and studied Diatoms before the advent of TEM, SEM will remember the advocates of doom and gloom saying these would be the death of amateurs. As it turned out it was far from the truth with the instruments often showing details which had been seen by amateurs and in fact the reverse was also true we often went back to our slides after seeing an SEM photo and lo and behold we now see what has been missed before.
         This brings me to my main point, do not throw your dummies out of the pram over such an issue as names of Diatoms, I was very intimidated by the naming of Diatoms until I joined this group and Charles has been instrumental in my starting to enjoy this, true my main reason for avoiding that was lack of literature and with each of Charles's posting I learned a little more.
          Charles if you are serious about throwing in the towel would you consider exchanging emails with me and continue your excellent teachings? I would be honoured and do not give a damn about if you are up to date within the last hour.

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