Cephalopod Arms

DWhatley

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Level_Head pointed out this article in The Journal of Experimental Zoology Volume 31 (1920)- William Keith Brooks, Wistar Institute of Anatomy and Biology, American Society of Zoologists, article by Mathilde M. Lange that discusses his observations and opinions as to what happens when an octopus arm is amputated. I found this a good paper to read on what to expect after an animal looses (or has lost before arrival) a part of an arm. She references a book by Adolf Naef that was submitted for publication at the writing of this document and a pdf copy can be found here.

Items of note (there is a good, point summary at the end of the paper):

-The arm does not bleed after amputation but DOES bleed some 5 - 6 hours later and creates a blood clot coverage for the raw end

-The suckers nearest the cut end change alignment and remain misaligned for a period of time. The first signs of regeneration occur when the suckers return to their normal position

-Healing time seems to vary with age, location of the cut (the closer to the tip the faster the healing), and season (possibly temperature rather than season? Observation was faster in spring and slower in fall but no temperature differences were noted).

-Squid may completely replace an arm rather than regenerate one from the severed end. He was not able to fully observe regeneration in squid because the experimental animals did not live long enough to observe the process.

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maplichen

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Just to add, here is a great paper detailing regeneration in cuttlefish.

http://www.obs-banyuls.fr/Viemilieu/index.php/volume-56-2006/56-issue-2/562-article-13.html

I am doing some regenerative studies in the lab I work for, and have detailed a similar outline for arm regeneration progress in officinalis, pharonis and bandensis. Behaviorally these animals seem to bounce back within 12 hours or so and the time frame actually seems to be faster for us but there is significant variation in care and living conditions.
 

Tintenfisch

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D, thanks for posting these -- I knew I remembered seeing mention of some articles relevant to regeneration on here somewhere. Just reviewing a MSc thesis whose author might find these relevant. :thumbsup:

BTW, Lange was a woman :wink:
 

DWhatley

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Fixed the gender oversight :oops:

While you are searching, adding to the post would be great. I didn't come up with them but found the article interesting enough to try to keep an on-going subject post. One of the things I suspect is that if an arm is damaged, it will not regenerate the damaged part but only heal it. One of my animals had a bad place in its arm (came that way not acquired in the tank) and I wondered if removing the arm at the damage would allow for a better replacement. I did not experiment because he could use the arm comfortably but was curious about this form of treatment should I keep on with damage so sever that the arm was not fully functional. Hard choices when the animal is alive :biggrin2: and it would help to have a positive observation from someone else before I would want to consider it.
 

Tintenfisch

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Most of the other papers about it that spring to mind are anecdotal observations of regenerating appendages observed on dead specimens; Aldrich (1968 -- PDF here) had an Archi with a regenerating tentacle, I had an Onykia robusta with the same in the thesis/monograph, and Bello (1995) appears to have looked specifically at hectocotylus regeneration in sepiolids, to name a few. William Kier has done a lot of work on ceph musculature, including arms, and probably has some observations on regeneration somewhere, too.
 

Level_Head

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How about skin and muscle regeneration not on the the arms? There are call-outs in the literature that specifically note the lack of regenerative ability of cephalopod gonads, for example.

In humans the liver can regenerate under some conditions (it is fairly unique in that) and skin and cartilage continue to grow in adults (sometimes unfortunate). If an octopus lost a chunk of tissue from the body — an animal bite, for example — how well could it heal/regrow? You might have some anecdotal observations from your own specimens.
 

DWhatley

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Interesting considereations. Antecdotally, we have noted that chromataphores don't regenerate where the skin is damaged. Cuttles will live for a time with serious but burn but I don't know if they sruvive and repair the damage when the cuttle bone protrudes through the skin. I don't think we have anything on the site about internal organ damage repair. Removed optic glands don't regenerate :biggrin2:
 

Level_Head

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DWhatley;187215 said:
Cuttles will live for a time with serious but burn
I was puzzled trying to imagine this — they don't even have a clear "but" and I'm not sure how it could get burned.

In fact, that lack in cephalopods is something I've written about, rather whimsically, in the case of an ambiguous fossil:
http://level-head.livejournal.com/465978.html

It starts out:
There were six fossil scientists
To early life inclined
Who saw a Nectocaris
They recently did find
That each by speculation
Might guess the creature’s kind
The link has the rest.

Nevertheless, you're describing some significant injury no doubt. The next situation, the protruding cuttlebone, sounds sad indeed. I recall reading in papers (mostly from the 1950s and 1960s) of octopuses that had been trained to perform some particular task and then had half their brains removed to see if there was a memory of the task for the arms on one side. Various other partial-brain-removal experiments were described; it was an area of active interest (and still is).

In fact, one of those studies featured a particularly clever octopus identified as Specimen NDF -- and it was from this octopus that Clan Nadef got its name.

There was no description of major brain tissue regeneration in these animals, though there was a little bit of repair as I recall.

DWhatley;187215 said:
Removed optic glands don't regenerate. :biggrin2:
Indeed they do not. Perhaps this will be a useful thing for them to know someday. 8-)
 

DWhatley

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However, I failed to point out (where you did not in your FIRST novel) that if the gland is re-implanted, it will then grow.

I suppose it depends on how you define butt. If it is the posterior and agree that eyes are anterior then they have one and when it rams the glass the skin gets abraded. Ramming it hard enough or often enough will ultimately expose the cuttlebone. This is not generally a problem (but happens) with the Sepia bandensis that we keep but is a major problem for the larger animals.

If butt has a function associated with it then I will agree it would be hard to define and would have to be some where near the head and not associated with the body :roll:
 

mucktopus

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Wow a pdf of Naef! Now I can have it with me in the field! Excellent find D!
 

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