my new octo

Discussion in 'ID Requests' started by bobby a., Sep 29, 2007.

  1. bobby a.

    bobby a. Cuttlefish Registered

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    trying to figure out what species the octo i got is the lfs said he is a common atlantic pygmy octopus.... does anyone know what scientific species name goes with this......

    my personal opinion is o. briareus....... i cant find anything on "common atlantic pygmy"..... im leaning towards they dont know what they are talking about.

    will have a picture soon.
    any help will be appretiated
    bobby
     
  2. Scuba Kid

    Scuba Kid Cuttlefish Registered

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    I would lean toward O. Mercatoris. They are fairly common in the trade and are a dwarf species from the Atlantic.
     
  3. Animal Mother

    Animal Mother Architeuthis Supporter

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    Yes if it is indeed an Atlantic pygmy octopus it's most likely either Joubini or Mercatoris.

    Why do you think it's a Briareus?
     
  4. shipposhack

    shipposhack Haliphron Atlanticus Registered

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    Animal Mother is right that a common dwarf for the atlantic (caribbean, really) would be either O. Mercatoris or O. Joubini. However if your octo was caught in Africa, S. America, or somewhere else with cold water there's a good chance it is something else. I wouldn't even trust too much that it's a dwarf. Look for dwarf features (larger than normal eyes, filter feeding) and behavior (nocturnal, shy) to try and sort out whether or not he really is a dwarf. Until you get a picture, there isn't much we can do to help you ID your octopus.
     
  5. bobby a.

    bobby a. Cuttlefish Registered

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    i think it is briareus just from comparing photos.... like i said i dont think it is "atlantic pigmy" the guy at the store said that when he saw it on the list it just said octopus...... he is not O. Mercatoris... well just from the pictures i could find to compare.... it has only been a snow white with thin black lines and it changed to a deep brown/red. he also has small points all over his mantle and two above each eye like eye lashes...i figured its color at the store was due to stress....
    he was out this morning for a few min. i havent gotten any crabs for him so i gave him a krill on a feeding stick... he came right up the stick and tried to pull it into the hole he made last night... he is really strong and has a mantle size of about 2.5-3 in.
     
  6. bobby a.

    bobby a. Cuttlefish Registered

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    just looked a O. Joubini... thats not him either... his eyes are normal size in comparison to his mantle.... and instead of round puples they are thin rectangle shaped... and no not shy at all. he came right out this mourning to get the krill with the lights on and everything

    yeah i know that its not much help without a picture... thanks anyway guys.
     
  7. Animal Mother

    Animal Mother Architeuthis Supporter

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    Well, it sounds diurnal, and a 2.5-3 inch mantle so you can rule out "Pygmy" as you have. Briareus are generally nocturnal, but who knows. You might be right, they aren't rare.

    All octopuses have rectangular pupils.
     
  8. shipposhack

    shipposhack Haliphron Atlanticus Registered

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    How do they know it's Atlantic if the list just said octopus? Does he have any webbing in between his arms? Also do his arms seem extra-long? It sounds to me like you might have A. Aculeatus, but he would not be from the Atlantic.

    I'm don't want to sound like a know-it-all, but the pupil is actually round. Neogonodactylus has a wonderful picture that depicts it: http://www.tonmo.com/gallery/showphoto.php?photo=562 . The eye is a rectangle shape though.
     
  9. monty

    monty Colossal Squid Staff Member Supporter

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    With a set up like that, now I don't want to sound like a know-it-all either, but unless I'm mistaken, the picture shows the rectangular pupil, but that inside the eye there's a circular image, which I think (and Roy's description seems to back this up) is a visible image of something round in the environment, probably a big lamp that a professional photographer used to light the octo, I'm guessing.

    Pupil shapes are really interesting, particularly in cephalopods. Despite this nitpick, you're on the right track, because most of the eye parts are round: the retina, lens, and so forth are all round. Humans, and most other animals, and squids all have a round pupil, but a lot of animals have other shapes... cats have the vertical slits, cuttlefish have a strange W shape, octos have the wide, short rectangle, and cetaceans have a pupil that has some two-slit arrangement that uses the lens for focus underwater, while using the slits to make something like a pinhole camera to see in air.

    Hanlon & Messenger don't discuss pupil shape, but they do point out that cuttles and octos have a horizontal stripe of longer, thinner receptor cells in the center of the retina, which probably give extra sensitivity in the horizontal plane, which makes sense as they live near the bottom. It's likely that the pupil shapes help utilize this strip better... and the cuttle has both the strip and an area near the posterior part of the eye that's even more optimized for looking forward to aim its tentacle stripes, so maybe the "W" shape has to do with focusing in two different ways-- look all around at bottom level, and look forward for lunch! Of course, the cuttle needs to look up for predators above, and down to look at the texture that it's matching, too.
     

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