On cranchiid feeding posture

Discussion in 'Cranchiidae' started by OB, Nov 2, 2005.

  1. OB

    OB Colossal Squid Staff Member Moderator

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    I came accross this interesting set of stills of (most likely) Helicocranchia sp., taken on 31 march 2003 by the MBARI Gulf of California expedition (Cerralvo Trough). It shows the squid in a position as postulated by SOS for Mesonychoteuthis. I found this to be a nice bit of supporting evidence :twocents:
     
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  2. main_board

    main_board Vampyroteuthis Supporter

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    Man cranchiids are wierd! So many of them look alien, more like a jellyfish and their kin than any sort of cephalopod. Great pictures though! Where are the threads on which Steve talks about the messie positioning? I don't remember reading those.

    Cheers!
     
  3. OB

    OB Colossal Squid Staff Member Moderator

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    Urrrr, let me think. It wasn't so much a focussed thread per se, more a remark in one or two of them, alluding to a "position paper" on M. hamiltonii postion.... Maybe Steve could illuminate the current status of the paper, perhaps it's still under peer review?

    PS: this is what's commonly known as the Cockatoo position, a bit like the J posture, gone horribly wrong :goofysca:
     
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  4. Phil

    Phil Colossal Squid Supporter Registered

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    I believe this passive-drift mode has been dubbed the 'cockatoo posture', and (I think) is peculiar to cranchiids. I'm sure I've read that the giant Megalocranchia has been observed doing this too. I'm not sure what advantage is to be gained from drifting so other than energy conservation. Maybe such crachiids tend to strike from below and this is passive - but prepared - behaviour?

    (Edit, oops, sorry ob, didn't mean to repeat you. Must read before I leap in future....)
     
  5. Clem

    Clem Architeuthis Supporter Registered

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    Hi,

    Apologies if it was posted and discussed elsewhere, but this link still ought to be in this thread:Helicocranchia, The Piglet Squid (The image is part of a photo gallery; click the lower right square.) Many features of interest to peer at, and the piglet gag always makes me laugh. In addition, there's a different shot (lower angle) at the online New Scientist from July of 2006.

    Cheers,
    Adam
     
  6. fluffysquid

    fluffysquid Vampyroteuthis Registered

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    piglett squid!!!! eeeeeee! that made my day.
     
  7. Steve O'Shea

    Steve O'Shea Colossal Squid Supporter

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    Whether the squid hold the arms up or down probably depends on the arm formula; those with the dorsal arms shortest (of the 4 pairs)probably hold them up (all arms), whereas those with the dorsal arms longest hold the arm crown down; that's the theory - I'd love to put it to the test. It probably wouldn't take much to do.
     
  8. Tintenfisch

    Tintenfisch Architeuthis Staff Member Moderator

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    Taonius does it too - see the pic on the Cephalopods in Action page, which is a still from the T. pavo video on this page. There's a video of Teuthowenia doing the cockatoo (too).
     
  9. Clem

    Clem Architeuthis Supporter Registered

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    ...and below, another Taonian, from MBARI rov footage. Adoption of the cockatoo posture seems to allow the eyes to move forward and closer together...improved depth perception? Useful for targeting prey and judging distance from intrusive cameras...:roll: What's the evidence that the posture is related to feeding? Direct observations in the wild or a cranchiid specimen in a holding tank? I can see how it could work, just curious to know the facts.

    Cheers,
    Clem
     

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  10. tonmo

    tonmo Titanites Staff Member Webmaster Moderator

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    That is truly weird, and equally cool...
     

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