Spirula spirula info. please!

Discussion in 'Spirulidae' started by BigSquid8Me, Mar 10, 2004.

  1. BigSquid8Me

    BigSquid8Me Blue Ring Registered

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    Hey all!
    I'm doing an amature (most amature . . . I'm a high school student) research project on Spirula spirula, but I have very few resources! I understand that Spirula is not a very well known species/genus, but it really fascinates me and I've been trying to get ahold of any info I can. I have "Cephalopod Behaviour" by Hanlon and Messenger, and Dr. James Wood as a guide/mentor, but I think I'm going to need a little bit more if I'm going to pull this off!
    Any ideas?

    ~BigSquid
     
  2. Tintenfisch

    Tintenfisch Architeuthis Staff Member Moderator

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    If you search the References section of Cephbase you get quite a few; among them:

    Bruun A.F. 1943. The biology of Spirula spirula. Dana report. 24: 1-39.

    Denton E.J., Gilpin-Brown J.B. and J.V. Howarth 1967. On the buoyancy of Spirula spirula. Journal of Marine Biological Association of the United Kingdom. 47: 181-191.

    Herring P.J., Clarke M.R., von Boletzky S. and K.P. Ryan 1981. The light organs of Sepiola atlantica and Spirula spirula (Mollusca: Cephalopoda): Bacterial and intrinsic systems in the order Sepiodea. Journal of Marine Biological Association of the United Kingdom. 61: 901-916.

    :read:
     
  3. BigSquid8Me

    BigSquid8Me Blue Ring Registered

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    Thanks a lot Tintenfisch! You wouldn't happen to know though how I would happen to get ahold of these references, would you?

    BigSquid
     
  4. Phil

    Phil Colossal Squid Supporter Registered

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    Hi, BigSquid8Me,

    This link might be of use:

    http://tolweb.org/tree?group=Spirula_spirula&contgroup=Sepioid_families

    The Tree of Life pages are really very useful and full of detail. It may also be useful using the search function at the top of the screen on TONMO and inputting 'Spirula', you should then find a number of references to the animal under 'Physiology' and 'Fossils'. The squid occupies an interesting taxonomic postion and is a bit of a 'living fossil' itself.

    Near identical Spirulidae are known at least since the Aquitainian of the Miocene period, about 23 million years ago and specimens of this age have been found in Japan. I can supply you with a reference for this tomorrow if you would like it.

    Please help youself to this image if it is of use (it belongs to me!):

    (TONMO.com edit - link no longer exists - forum software changed)

    Hope that is of some help,

    Cheers,

    Phil
     
  5. BigSquid8Me

    BigSquid8Me Blue Ring Registered

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    Excellente!
    Thanks a lot! I had looked at Tree of Life before, but not in the fossil and physiology areas. Thanks!


    BigSquid8Me
     
  6. WhiteKiboko

    WhiteKiboko Colossal Squid Supporter Registered

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    Try local colleges or your local libraries if you're lucky... depending on where you go, a lot of journals can be found in digital form...
     
  7. monty

    monty Colossal Squid Staff Member Supporter

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    There are a few pages on Spirula in Nixon & Young, _The Brains and Lives of Cephalopods_ if you can find a library near you that has that, too.

    edit: Nixon & Young refer to an ancient Nature paper:

    Schmidt, J. (1922) Live specimens of Spirula. Nature, London, 110, 788-90

    many universities have been subscribing to Nature for many years, so that may not be too tough to find, even though it's so old. Of course, it's only 3 pages long, and the info isn't likely to be very current...
     
  8. monty

    monty Colossal Squid Staff Member Supporter

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    I'd really love to hear all of you cladists describe your views on Spirula, actually-- it seems to fly in the face of the common belief that the specialized tentacles of the decapods developed after the coleoids lost their chambered shells...
     
  9. monty

    monty Colossal Squid Staff Member Supporter

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    As an extension to my earlier question/observation about the 8-arms-2-tentacles aspect of spirula being at odds with the spiral shell, I also note that Nixon & Young report that slow and awkward little spirula has a giant fiber system related to that of other decapods, which would seem to suggest that fast squiddiness evolved before the loss of the coiled, chambered shell's buoyancy mechanism. The siphuncle in spirula is also positioned ventrally along the inside of the spiral, rather than centrally as in Nautilus, so I'm pretty sure that this is the only living ceph with this arrangement. (see the green picture at http://tolweb.org/Spirula_spirula/19989 )

    I'm sure Kevin and Phil can list off the various ammonids and nautiloids that share this arrangement, but modern nautilus has a central siphuncle. (as an aside, I was surprised that I couldn't find much in siphuncle location in the otherwise brilliant "fossils and history" articles... perhaps someone with a more encyclopedic knowledge of such things could remedy that? or perhaps my article searching skills have failed me and someone will point out where I missed it...)

    As a starter, and a hat tip memorial to Sir Denton, I'll transcribe a bit from Ward The Natural History of Nautilus(p.234):

    Figure 7.19 shows a "tortonic heteromorphic ammonite" which has a siphuncle placed strategically to always be above the fluid level. The "decoupling" mentioned above means that the gas/fluid ratio in a chamber can be changed much more easily when the siphuncle's opening is not under the cameral liquid. To reduce confusion, spirula's orientation of the shell is the opposite of Nautilus, in that the last opening faces straight down rather than horizontally, so there is a little confusion about dorsal vs ventral, but the unusual configuration Spirula has is that the siphuncle is on the inside of the spiral, not the center as in Nautilus or the outside as in many ammonoids.

    edit: I neglected to mention that this post was inspired by a discussion with hallucigenia, who got me thinking about spirula again and helped me past some of my paleo-ignorance, as well as having a "find links, look in books, and discuss results" IM session (much like this) :oops:
     
  10. Architeuthoceras

    Architeuthoceras Architeuthis Staff Member Moderator

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    Spirula has an endogastric shell, it coils the opposite way (ventrally) of (?most) ammonoids and Nautilus, The shell of ammonoids and Nautilus are exogastric, their shell coils above the head (dorsally).

    In this thread, more is said about the different layers of shell in the spirulids, and that maybe they are more like the the orthoconic bactritids than coiled ammonoids.
     
  11. monty

    monty Colossal Squid Staff Member Supporter

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    thanks! Knowing the word endogastric led me to this: http://www.thecephalopodpage.org/FosCephs.php which answers a few questions and raises some as well.

    It seems like someone should be doing some genomic analysis to compare spirula to nautilus and to other coleoids. And the cirrate octopods and vamyroteuthis to more typical coleoids.

    It still seems to me that spirula's shell geometry throws a big wrench into all the standard clade diagrams, and yet it seems to just not get discussed much... but maybe I'm just not looking in the right places, hence this thread! (the usual "I am an ignorant computer scientist, not a real bio-/palaeo-/teuth- or other -ologist" caveats apply)
     
  12. cuttlegirl

    cuttlegirl Colossal Squid Supporter Registered

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    I will have to search a little, but I have some SEMs that I took of Spirula's siphuncle - If I can find them, I will scan them and post them...
     

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