Indonesian from Live Aquaria

DWhatley

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We normally assume either a Macropus or Abdopus (typically labled aculeatus) from Live Aquaria when they are labled Indonesian. However, occasionally we see a very small animal that does not live very long and have labled it abaculus (Roy's review of these suggest incorrect labeling). Dink had a very small mantle and relatively long arms. Her condition never allowed viewing of much body patterning but at her death, I noticed an unusual trait and would like a suggested id. The siphon is attached to the back of the head, fully outside the mantle. I have never taken notice of the back side of the mantle and never thought to photograph it after death but this immediately struck me as unusual.




 

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I strongly suspect that that was damage to the mantle.

EDIT: I have a verification from Dr. Young - yes, that Dr. Young - that "normal octopuses aren't going to look like that". Is this specimen fixed in a fixative? The mantle, I've noticed, tends to contract fairly strongly in octopuses, which makes them difficult to dissect.

If your octopus looked like that while it was alive, it was essentially on its way out anyway. I don't know if this would give you reason to suspect mishandling, but if this isn't an effect of the fixation, I'm inclined to think something went wrong in the shipping process.
 
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No fixative at the time of the photo. It definitely looked immediately odd to me when I picked her up after she expired. I did not get a look at the underside of he mantle before putting her in the tank (nor would it have occured to me to do so). There is nothing in the tank that would do mantle damage (considering I raised an O. briareus from hatchling in the same tank with the same occupants - serpent stars, cowrie, pencil urchins, gorgonian and benign polyps) to a living animal and she was sequestered while still alive but fading. You can see that the arms had been shortened (likely precollection as there were little tips growing back) but this is normal. The top of the mantle showed a white patch that I did not see color up the few times she would flash brown but I saw no real scars. The arms did show some white areas and her overall color was a blatant sign she would not survive.

Any suggestions on what would be able to remove a chunk of mantle that smoothly and from the underside? I suspected an odd species because it does not look torn or ragged and assumed it was natural but unusual.
 
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Is the mantle contracted? Examine the inside of the mantle and the area around the edges of the siphon to see if there's any possible evidence of ripping. It could have happened while she was alive, as well, and that might have caused some healing to occur.

It's possible she could have been mishandled or something else happened before collection that caused the siphon to pop out of her mantle.
 
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The siphon did not pop out, it is attached below the existing mantle. I am not sure that the arrangement is not natural (either for the species for for this specific animal). The siphon is fully below the mantle and could never have been inside even with considerable extension. The mantle would have had to have the bottom 1/2" or more removed (possibly it has moved upward but the oddity struck me immediately) and there should be some kind of ripping or dead skin if anything recent occured. The back edge is smooth and semetrically shaped. I have a couple of other animals in formalin or alcohol. When I put all of them in alcohol for a while, I will take them out and look closely at the mantle backs.

It is not practicle nor recommended to more than casually examine a new animal. Octopuses are sensative to stress and acclimating them to a new environment is already a major stress event (in addition to the journey to its new home). I don't, but it is often recommended to water acclimate in as low a light as possible and then leave them in a dark tank for 24 hours. There is nothing to be gained or changed if the animal is in poor health or has suffered during shipping so giving it the best shot possible during its first two weeks includes minimizing stress levels.
 
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Nothing is out of place, I am beginning to wonder if this one was exposed to air bubbles under the mantle. Roy has mentioned that this can be a problem and the recommendation has been to run any kind of areation bubbler in a sump or very near the surface but we have not seen it happen on the forum and the symptoms have not been listed. If air was trapped in the mantle, it might force it upward but the distance seems extreme for this thought.
 
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Could it be that it was simply on its way out and after death the mantle contracted? It looked pretty bad in the arrival pics, and it doesn't really look like there is any damage, just a contracted mantle.
 
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I have thought of that Rich but I have never seen this in other deaths. I took a quick look at the preserved ones I have waiting on the next request and the siphons are not exposed. When I have a few minutes (and things will stop breaking), I will try to get a photo of this one compared to the O. briareus of similar size.
 
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Does her mantle feel thickened and contracted?

I have my doubts that that's an aculeatus, at least, after looking at two under the scope. There isn't that dip in the posterior part of the siphon, although I could be looking at it wrong. I'll see if I can look at an abaculus and a few macropuses.

Her gills are really, really exposed.
 
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Very hard to have a clue on this one but it did not look typical of either the small macropus (I have kept two of them) or aculeatus but because of its condition, I would not bet against abdopus (nor would I put money on the complex though). The fun part about Octo ID is that many can look so very different while some, like the Wunderpus are easy. The little joubini I have probably has the widest range of looks and any one photo could be several animals. An advantage you have working with dead animals is looking closely at body parts without the distractions of color and pattern changes but you miss the wonder of these looks as well. If you would like to have a closer look, PM me your address and I will send her in alcohol (she is in formalin now so is perserved).
 
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UPDATE

Talked to Mike Vecchione. He said the mantle'll just contract like that postmortem. The mantle is generally not attached to the siphon, apparently.

Thales, you had the correct idea about that.

Re ID, since this is an Indonesian octopod, ask mucktopus.
 
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