how to identify a squid from its tentacle

Discussion in 'Physiology and Biology' started by cayucos, May 10, 2010.

  1. cayucos

    cayucos Cuttlefish Registered

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    Need help please. In a story I'm writing, someone comes across a squid tentacle. The person needs to identify it as a Humboldt, as opposed to market squid. Would both kinds of squid have hooks, or teeth, on the suckers? Is there an identifiable difference?

    Thanks!
     
  2. monty

    monty Colossal Squid Staff Member Supporter

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    :welcome:

    Nesis says Humboldts ( Dosidicus gigas ) have "No suckers with denticulate rings in carpal part of club proximal to first knob." In regions where humboldts live, the market squid would be Loligo opelescens... there's no specific reference to clubs in Nesis at a glance, but it sounds like in general the Loligo species have distinctive sucker rings.

    Probably Steve or Kat can help more... but maybe this is a start...
     
  3. cayucos

    cayucos Cuttlefish Registered

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    Hey thanks. That's exactly the kind of specific info I'm in need of. Would also love to find photos of both tentacles, so I can describe what they look like. Off to google, and I'll keep an eye on this thread should more experts chime in.

    Appreciate the help and warm welcome.
     
  4. cayucos

    cayucos Cuttlefish Registered

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    PS: what is Nesis? Sorry, I'm just learning the cephalopod ropes
     
  5. monty

    monty Colossal Squid Staff Member Supporter

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    Nesis is a book, Cephalopods of the World by Kir Nesis.
     
  6. cayucos

    cayucos Cuttlefish Registered

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    Ah, thanks.
     
  7. Jean

    Jean Colossal Squid Supporter

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    The sucker ring dentition is used to id squid from just an arm or bit of an arm, usually you would need a good set of voucher specimens ie rings of known species from a known position on a known arm (they can vary arm to arm and sucker to sucker) see picture 1 (tolweb) for a sucker ring from Nototodarus hawaiiensis and picture 2 (fromunderwater times.com) for one from Dosidicus gigas, the Humbolt.
     

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  8. Steve O'Shea

    Steve O'Shea Colossal Squid Supporter

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    .... and both are ommastrephids (family Ommastrephidae), and neither has hooks. The differences in the club morphology and sucker-ring dentition are rather slight
     
  9. cayucos

    cayucos Cuttlefish Registered

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    Many thanks to Jean and Steve, as well.

    I thought I'd educated myself pretty well, via google, on squids and suckers but I see now I've found the mother lode of online cephalopod education.
     
  10. Jean

    Jean Colossal Squid Supporter

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    True, but the teeth on the narrower section of the ring in N. hawaiiensis are quite rectangular (yes I know my sucker ring terminology isn't up to scratch!), whereas the ones on the D. gigas ring are quite triangular and all are more pointed. Course it doesn't say which arms the pics are from!
     
  11. cayucos

    cayucos Cuttlefish Registered

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    Rectangular teeth versus triangular is a great easily recognized difference for my story character, who is vaguely familiar with the market squid in his fishing town, but no expert.

    Thanks.
     
  12. Jean

    Jean Colossal Squid Supporter

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    You're welcome BUT one proviso I have no idea what the sucker rings on Loligo opalescens look like they could be different again, Can you get a hold of a market squid and have a look?
     
  13. cuttlegirl

    cuttlegirl Colossal Squid Supporter Registered

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  14. Tintenfisch

    Tintenfisch Architeuthis Staff Member Moderator

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    One possibly minor hiccup here - 'tentacle' and 'arm' are not the same. So if your character finds a tentacle (one of the two longer appendages with suckers mostly clustered at the tip), the triangular/square teeth discussed above on the arm suckers will not apply. But if the character finds a piece of arm, you're all right. :wink:
     
  15. cayucos

    cayucos Cuttlefish Registered

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    Jean: good point. I'll have the chance this summer to check out market squid at the place where my book is based. And then I can describe it in just the way that a non-expert would see it.

    Cuttlegirl: thanks for the link. I'll go look...

    Tintenfisch: oooh, whoops. So, say, the triangular teeth on the Humboldt are ONLY on the arm suckers? Different teeth on the tentacle suckers? Well, my character will not know the diff between an arm and a tentacle (as I'm just learning :). But I'd best know.

    Thanks all.
     
  16. Jean

    Jean Colossal Squid Supporter

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    Tentacles usually don't have suckers all the way down, only on the upper area (furthest from the mouth) called the club, arms have suckers tip to mouth
     
  17. cayucos

    cayucos Cuttlefish Registered

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    Thanks for the clarification.
     
  18. Steve O'Shea

    Steve O'Shea Colossal Squid Supporter

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    ... tiny point of clarification ... except for the 'suckers and knobs' that can extend the length of the tentacle that might serve to hold the two together for their length when the animal is live
     
  19. cayucos

    cayucos Cuttlefish Registered

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    I do love clarifications. So easy to research something and >think< I've got it right, but for those pesky details.

    So, to be sure I've really got it right: my character sees a piece of tentacle (which will be the club end), or piece of arm (the club (?) end). The teeth on the suckers will differ, depending on whether the specimen is tentacle or arm. I'm still not sure what the teeth on the Humboldt tentacle club look like.

    My character would not know that difference. But I do need her to be able to identify it as coming from a Humboldt, as opposed to the local market squid (Loligo opalescens, as I've learned--don't know that my character will progress to the Latin). Size would be one important marker. Teeth would be another. I'm not yet sure whether it's important, in my plot, if the specimen is tentacle or arm, but dramatically nice sharp teeth would be good.

    Thanks again to all who have posted in response.
     
  20. Steve O'Shea

    Steve O'Shea Colossal Squid Supporter

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    The beak would be even more definitive; cannot you have a Sherlock that looks at two characters for a conclusive?
     

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