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Discussion in 'Name that Critter' started by florentny, May 26, 2004.

  1. archman

    archman Marine Scientist

    # of Dives: 200 - 499
    Location: Florida
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    Disregarding the rude and surprising comments concerning my "know-it-all postings on marine life that are annoying and sometimes wrong", you appear to have your observations of sea pens backwards. Having my older copy of Barnes' conveniently sitting right beside me, let me quote something most marine invertebrate zoologists are quite familiar with.
    From pp. 137-137 of Barnes Invertebrate Zoology (5th edition).
    The "primary polyp" is also commonly referred to as the "stalk" or "axial polyp". You can have absurdly short stalks like in Renilla, very long ones like in Umbellula, but most commonly you'll get the intermediate sized ones like in Virgularia and Stylatula. I'm only commenting on genera I'm well familiar with from our research and teaching collections, mind you. Pennatulaceans are not my taxonomic specialty.
    From Florenty's photo, the axial polyp is not visible. And while from an ecological sense I'd rather go with it being an egg case, we'll argue the sea pen for the sake of accuracy.
    In this case what you're seeing are the secondary polyps coming off from the upper primary polyp, also referred to as the "quill of the pen" in Virgularia forms. For these and related genera your secondary polyps will not assume a cylindrical shape from the upper stalk, but more like the one in the photograph. However you can most assuredly have a "cylindrical" form. An internet search of Stylatula should show this quite clearly... looks like stick candy. And if want to see a wholly different type of sea pen morphology, look up Umbellula, which looks like a pinwheel. Glows in the dark too, although I've never been able to get my trawl specimens to do this. A multiple hour ride through several thousand feet of water tends to put animals in a black mood.

    As for pennatulaceans requiring soft sediments for attachment, that's dead on and can be referred to in my first post (#3 I think). The lower end of the axial polyp is technically referred to as the "physa" or "peduncle", and works by digging into the bottom and then becoming swollen with actively pumped seawater. In essence it performs much like dredge anchors. And as far as I know ALL pennatulaceans are epipelic (dwelling atop sediments), not "most all cases". If you know of an exception please post it, as I would like to append it to my notes.

    EDITED ******* The egg case theory for instance is very good and most likely is what the unidentified feature is. Not from direct visual observation mind but from the reported depth and location of the photo, and that gorgonian (a plexaurid of some type) sitting right next to it.

    I back up most if not all of my statements regarding marine life on this board, and do not take offense if they turn out to be incorrect. I expect other posters to return the courtesy.
     
  2. John H. Moore

    John H. Moore Nassau Grouper

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    From placement I would guess not a sea pen. But the photo makes it hard to tell. Definitely not an undisturbed sea pen. But have you ever harassed the heck out of one? ...they pull all the outer, feathery stuff in and way down, leaving just the quill straight up with a mass of bunched up, curved stuff at the base. In the photo, the out-of-focus straight bit doesn't look like a quill, but... and it's hard to see whether it's a part of the unknown or the gorgonian...

    Could I imagine that this is a really harassed sea pen? Yes. But I doubt it is.

    John
     
  3. archman

    archman Marine Scientist

    # of Dives: 200 - 499
    Location: Florida
    5,018
    90
    48
    When you "harass the heck out of" the things, they retract their secondary polyps (which are mostly of the feeding "autozooid" type). That would be the outer, feathery stuff I believe you're referring to. Some species I THINK will retract their axial polyp as well, I have a deep-sea video of something that looks like Funiculina doing that very thing. The kids love it.
    Even though I still think it's probably an egg case (someone please chime in about what laid the thing!), the "harassed" sea pen is quite plausible from an ecological standpoint. This critter would obviously be suffering from environmental stress due to it's reported depth and location, and animals can look pretty jacked up when they're not happy!
     
  4. Winton

    Winton Nassau Grouper

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    Scientific observation is so cool, wow, I really only have one question; are both of you PHDs in a field of study related to marine biology?

    P.S. Nice Pics, absoloutely not a clue as to what it is, not with any real certainty, sorry. :D
     
  5. SueMermaid

    SueMermaid Loggerhead Turtle

    # of Dives: 200 - 499
    Location: NJ
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    It always makes me wonder if someone can get so nasty over something this small, what's their everyday life really like? The venomous comments in this forum over inconsequential things will never cease to amaze me.
     
  6. glbirch

    glbirch Solo Diver

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    It can certainly detract from a discussion. I personally can't attach much weight to comments from people who can't practice basic civility in a public forum.
     
  7. jlyle

    jlyle Loggerhead Turtle

    # of Dives: 2,500 - 4,999
    Location: Palos Verdes Peninsula, California
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    Alan is correct. What you saw is the egg case of the West Indian Chank, a type of conch.

    DSAO
     
  8. archman

    archman Marine Scientist

    # of Dives: 200 - 499
    Location: Florida
    5,018
    90
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    Thanks for the heads up jlyle. I'll have to look that species of conch up, never heard of it. Do you know the species name, by chance? Have any links to photos of the egg case or adult animal?

    ****edited****
    Just looked the thing up myself. http://www.gastropods.com/2/Shell_1512.html

    Turbinella angulata is the name for the West Indian Chank. After looking at the thing, I'm painfully wondering how many shells like this are mislabeled as young Horse Conchs! I KNOW I could have done it, and everybody else I know too! From another resource, it is said that Yucatan locals refer to the Horse Conch as the "Red Conch" and the Chank as the "Black Conch". I think this is applied to the general colour of the foot and mantle tissues, but cannot verify it... yet.

    I checked our teaching collections and none of our gastropod egg cases fit the bill. We have mostly stuff from moon snails and other conchs, however. Can't find an pic online of Turbinella's egg case either. Dang.

    Also came across this WONDERFUL online shell ID resource. If you don't know about it already, check it out! Heck, bookmark it! They have a "shell identification forum" and lots of other great stuff.
    http://www.seashell-collector.com/index.htm
     
  9. archman

    archman Marine Scientist

    # of Dives: 200 - 499
    Location: Florida
    5,018
    90
    48
    What the heck, I guess it's about time to toot my own horn on this board. Humble is taught real well in Texas, perhaps TOO well. Got picked on far too much this last week on scubaboard, makes me feel icky.

    I'm a senior Ph.D. graduate student within the Biology Department of Texas A&M University, falling under the auspices of the zoology division. I work directly under Dr. Mary Wicksten, foremost authority on California crabs and shrimps, international expert on reef fish cleaning behaviour and snapping shrimps, and member of the National Geographic Explorer's Club, mostly via scientific diving expeditions.

    I also work closely with Dr. Gilbert Rowe, a world-renowned biological oceanographer with a wealth of well-regarded research in deep-sea benthic studies all over the globe. I can't even BEGIN to describe his contributions to science. Suffice it to say only a handful of folks rank with him in the deep sea realm... Bob Ballard doesn't even make this cut.

    Having recently (January) passed my qualifying exams, I was judged by these two folks and two other in-field professors to academically qualify for a doctorate in my field. That's what "doctoral candidate" means in my member profile, and it's the most difficult hurdle in getting a Ph.D.. Now "all" I have to is complete and submit my research dissertation, which I plan on doing by Fall 2005 (hopefully).

    My dissertation research is unusually ambitious in scope, and concerns intensive study of the biodiversity and ecological structure of deep sea organisms within the Gulf of Mexico. I work with tens of thousands of animals, most living in recovered sediments and under 1mm in length. Theoretically I'm supposed to have viewed several dozen species nobody else has formally described before, possibly ever seen (that's how deep-sea macrofaunal study works, actually).
    Along with the teensy-weensies, I work with the more dramatic, bigger invertebrates (quite an array of bizarre creatures). Ecological interactions between the smaller and bigger faunas is my particular focus, so I have to be an expert on both groups, and all the critter types within each one. Functionally I will have a doctorate in marine ecology, but "zoology" is as close as our college lumps things.

    Along with all that ecological mess, I have also become a regional taxonomic and behavioral expert on starfishes and sea urchins, not just for the deep sea but shallow waters of the Gulf of Mexico and Caribbean Basins.

    Nobody alive knows more about the species, distribution and ecology of deep sea anemones in the Gulf of Mexico than me. I'm trying to get a manuscript on that published.

    The field of marine ecology is interdisciplinary, so frequently demands that we know a great deal about other scientific fields. For my research, massive amounts of invertebrate zoology, deep sea biology, statistics, and biological oceanography are needed. I possess a significantly greater amount of graduate training than most professors currently in marine ecology... I prefer to be slow and very thorough, my two professors demand a lot too.

    Outside my graduate research, I have professional training and expertise in marine botany, ichthyology, tropical coral reefs, wetlands, limnology, and environmental policy, and a bunch of others. Specific habitats I have expertise within are deep-sea, coastal Texas (we have a LOT of coast!), and Caribbean. I can and have taught at the college level for all three of these, in fact.

    In the Fall I run the undergraduate teaching laboratories for BIOL 440 (marine biology), and in the Spring, ZOOL 335 (invertebrate zoology). We have some of the finest invertebrate teaching collections in the country, and I am intimately acquainted with most of it. I take absurd pleasure in far exceeding normal teaching standards for these courses, and can proudly attest to their being well above average as a result. My fear is premature burnout, oh well.

    I've left out a great deal of information, like my undergraduate degree, field work, scientific expeditions, outreach, what I do during the summers, and most obviously, DIVING. Actually in comparison with many folks on this board I'm plain mediocre!

    Feels good to "let it out" for once, even if I didn't finish. Thanks Winton, although I guess this is a wee bit more than you had in mind. Whew!

    -arch
     
  10. David A

    David A Angel Fish

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    It is a bit worrying when things very quickly seem to get overheated (although in Archman's defence I don't think he was to blame for this), but sometimes I wonder if it's just the limitations of the printed word that causes the problems. We are no longer taught the art of good letter writing, as before the advent of e-mail, it was a dying form of communication. As a result I think we write the same words that we would speak in a verbal conversation, but that immediately suffers from lack of intanation. As a result, a phrase like "be serious" in written form can appear quite hostile, when if spoken it can be made to sound more light hearted.
    I'm sure that this problem could be avoided if only people would take care to read their own finished messages before posting them, and make sure that they convey not only the words, but the tone that they were trying to achieve. If in doubt, throw in a few deliberately nice or complimentary words to ensure that you are taken in the right way.
    Having said that, I think adshepard knew exactly what he was saying, and should consider switching to decaf!
    David
     

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