Pathological cephalopod

Teratology is so interesting — it gives us hints about the mechanisms driving developmental processes. In some cases, when you just have a few isolated instances, it can be frustrating, because there isn’t enough information to go much beyond speculation. Here’s one of those tantalizing cases: an octopus with branching tentacles.


Now that is fascinating. Look at limb formation as an abstract developmental problem in which you first have to initiate a protrusion from a specific place on the body wall; the protrusion has to elongate to a specific length; and it has to be patterned along its length. Cephalopod limb patterning doesn’t involve any branching elements, unlike vertebrate limbs which show a limited radiation of bony elements as you go distally. Vertebrates can exhibit phenomena like polydactyly which are basically counting errors or expansions of a field; the mechanisms for that don’t seem likely to be the case in cephalopods. What I’d guess is that this is an example of errors in initiation. Whatever the signal is that triggers limb extension from the body was triggered again and again as the arm grew, creating sub-arms and sub-sub-arms. This could be a consequence of a mutation that lifted normal constraints that pattern limb initiation (this animal lived for some time, and produced offspring with normal limbs, all of which died shortly after hatching, unfortunately, a result that is ambiguous in determining whether the problem is genetic), or it could be an environmental signal that mimics the normal developmental signal. You can’t tell from one dead octopus!

It’s still cool, though, and says we need more research on cephalopod development.


  1. True Bob says

    The better to EAT you with, my dear.

    I for one welcome our Centipus Myersii overlords.

  2. eyerock says

    Why waste on science what is so good to eat? All those extra pieces of sashimi…

  3. extatyzoma says

    its also possible that this animal was born looking normal(like its offspring) but only later grew its extra branches.

  4. says

    Let’s not discount the possibility of a shoggoth/octopus hybrid.

    Indeed very cool. And quite useful as an example of why science is just plain neat. You look at that picture and your initial reaction is likely to be “wow, look at that, weird”, but unless you’re terminally incurious that will be followed by “hmm, I wonder how that happens”.

  5. JoJo says

    The Old Ones are returning!

    I was surprised by one comment in the linked Pink Tentacle blog:

    Apparently there is no theory that fully explains the surplus tentacles, but they are believed to be the result of abnormal regeneration that occurred after the octopus suffered multiple injuries.

    I could understand if one or two tentacles had branches resulting from abnormal regeneration but from the pictures it appears that every tentacle branches. That must have been one massive injury the octopus suffered.

  6. True Bob says

    Yes, very weird. And two found near Japan. home of Gojiro. Coincidence? I think not.

    At first glance, I thought it was some kind of plant root.

  7. BruceH says

    I gotta say, the really interesting part of this case is not questions of morphology or other such sciencey mumbo-jumbo. No, the really interesting part is that the octopus reproduced. Meaning, of course, that she found some guy octopus who was willing to breed with her.


    What a freak. I guess it just goes to show that there really is someone for everyone.

  8. djlactin says

    with cephalopod intelligence and all: makes you wonder whether it knew it was … er … different.

  9. John C. Randolph says

    I wonder if the animal in question was able to control the additional appendages. Seems to me that a mollusc only has so much brain capacity for motor control, and having that many more limbs could be a fatal handicap.


  10. Hypatia says

    I keep staring at this octopus thinking that it would be a great visual aid for teaching kids how to factor.

  11. phisrow says

    Ok, I usually have a pretty stiff nerve for crawling horrors of the animal kingdom; but something about that one makes my skin crawl. I’m not at all sure that I’d want to see that one in motion.

    Definitely time to start scribbling elder signs on anything within reach.

  12. Jose says

    It’s just more support for the theory that cephalopods do not belong in the mollusk family, but instead evolved directly from trees.

  13. Arnosium Upinarum says


    Obviously this 96-tentacled fellow must not have found it’s extras to be too much of a hindrance in surviving, or it would not have grown to such a fair size, correct?

  14. Torbjörn Larsson, OM says

    abnormal regeneration

    Suddenly our own incapacity to regenerate seems a lot less of a hardship. Those things could happen often, as compared to defects at birth.

    I wonder if the animal in question was able to control the additional appendages. Seems to me that a mollusc only has so much brain capacity for motor control,

    I believe I just browsed, but unfortunately not read, a web text on cephalopods having quite a lot of their neural processing out in their arms. Surely the biologists here would know, but if so it doesn’t seem that primary motor control would be an issue.

    Anyway, cephalopods don’t have perfect coordination by any means, who does? IIRC (from Pharyngula, I think) giant squid males may impregnate their own arms in their frenzy to inject spermatophores into females.

  15. Enkidu says

    I wonder if the animal in question was able to control the additional appendages.

    That was my question. Did the brain automagically wire the extra neural pathways to control all those extra tentacles? If it bred in captivity, do they have video of it moving?

  16. JM Inc. says

    Are all those limbs fully functional? If so, that could be a valuable insight into the workings of the octopus nervous system. The various limbs, after all, are controlled each with a large degree of autonomy.

  17. NanuNanu says

    Very interesting! I found the most fascinating part is the fact that it lived to adulthood. Usually when I hear about odd growths like this it ends up being a fatal defect and you get two headed cats in jars.

  18. BliondRobin says

    Find the operator related to healing and limb regeneration.
    This looks like malformations due to skewed repair sequences experienced through ought the life of the organism which explains the ‘fractal’ appearance (don’t forget limb preference)

  19. amphiox says

    To jcr, #15,

    Since cephalopods possess a neural net in their arms that participiates in cognition to a much greater extent than the peripheral nervous system of invertebrates, this fellow might have been even more intelligent than normal!

  20. Cheezits says

    Am I the only one getting visions of a vertebrate with little hands at the ends of its fingers?

  21. Owlmirror says

    Might the fractal growth not be the result of something epigenetic, such as a viral infection?

    After wondering that, I was reminded of the “Tree Man”, whose extraneous growths are the result of a papilloma virus.

    Just Google (tree man). Here’s one of the first hits:

    No, they don’t look much like extra digits/limbs. But I think there is a sort of similarity in the fractal nature of the growths.

  22. LisaJ says

    #5, this is just what I was thinking.

    Was it necessarily some embryonic devlopmental process that lead to this extra branching, or did this take place after the animal was hatched? Perhaps a post-embryonic developmental process is to blame, or maybe an epigenetic mechanism that was modified by some environmental factor or perhaps a virus as was mentioned above.

    Where was this guy found? How cool would it be if there were more to study!

    #6, I was also thinking along these lines. What a beautiful analogy of the evolutionary tree!

  23. John says

    “Look at limb formation as an abstract developmental problem in which you first have to initiate a protrusion from a specific place on the body wall; the protrusion has to elongate to a specific length; and it has to be patterned along its length.”

    You’re sounding like an IDer. You don’t have to do any of those things; they were put in place by evolutionary mechanisms.

    The amazing thing is that we scientists have to wean ourselves from implicit telic assumptions. One sees this in cell biology quite often, too.

  24. Jordan Lund says

    There are two possible mechanisms for this…

    The first, as you state, is the initial growth of arms as the octopus is forming in the egg.

    But after birth, if an octopus loses an arm, it’s capable of regenerating.

    What if the regeneration mechanism went awry? Any subtle injury to the arm is being perceived as requiring new growth. Crawling around rocks, I’d imagine, would cause a soft-bodied octopus to get scraped up pretty good.

    If biology determined that each scrape needed a new arm we’d probably see something similar to this.

    Unfortunately it’s dead now, so we’ll never know. :^(

  25. Owlmirror says

    Unfortunately it’s dead now, so we’ll never know.

    Um, scientists do still have the body. The corpse could be examined forensically to see if the points where the tentacles split into branches in any way resemble an injury.

    For that matter, the cells could be examined for hypothetical epigenetic factors that might affect limb growth, such as viruses or chemical pollutants.

    And the genes of the octopus could be sequenced and compared to the genomes of normal members of its species, to see if it is indeed a mutant, with something unusual going on in one or more of the limb development segments of the genome.

    It’s just a matter of taking the time and energy to focus on the question fully.

  26. Travis says

    It’s plausible that they may have some of the same genetic sequences found in plants, they do predate modern plant life by quite some time. I think this may make some interesting insights into backwards evolution if properly studied. Keep up the good reporting!

  27. squidelicious says

    bifurcated limbs on cephalopods are not unheard of, be they the result of genetic mutation or the bodies abnormally aggressive healing process, but i have never seen anything to this extent before.

  28. Owlmirror says

    It’s plausible that they may have some of the same genetic sequences found in plants, they do predate modern plant life by quite some time.

    Wait, what?

  29. themadlolscientist, FCD says

    This is even scarier than the idea of cats with opposable thumbs.

  30. anonymous coward says

    I could be wrong, but I think distalless has a supressor, and I would guess that that’s the gene that’s mutated here.

  31. Longtime Lurker says

    Too bad it died before anyone could teach it to play an assortment of instruments. A one-octopus band would be more economical than a typical weddings/bar-mitzvahs/anything combo.

  32. DLC says

    (poe) Clearly this animal’s having extra limbs was Potentiated in it’s DNA by Teh Designer! !! Ewe Are Sooo Stoopid! @@!!!!

  33. amphiox says

    Travis #42: Although the appearance of cephalopods predates the appearance of land plants, the plant and animal lineages diverged from each other long before that. So if you are thinking that the fractal branching of the tentacles is somehow related to plant patterning genes that, say, produce the radial branching of stems and leaves, I would think that is unlikely.

    The genes responsible for patterning limbs in animals are probably hox genes, and plants use a different family of genes for their patterning. PZ wrote a post on this a while back, I think.

    Of course, plants and animals do share many genes, which they also share with fungi, bacteria, archaea, etc.

  34. black wolf says

    Ooooo, too much shoggy in that one!
    That’s what you get from making out drunk, C.
    Wake up from eternal slumber, get into heavy partying, and that’s how it ends.

  35. says

    Wow! Maybe that octopus was created by Whoever to show that none of our current theories about biology do well at explaining certain phenomena (no, that’s cheating, sorry). Gives one hope that as long as we are an extant species, there’ll always be something to whet our curiosity and inspire us to wonder.

    BTW, Save The Pacific Northwest Tree Octopus (link given by SEF, 7/19/2008 @ 11:20 AM)

    This is like something out of the DVD The Future is Wild (, loosely based on Dougal Dixon’s beautiful book of the same title ( So that‘s where they got their intelligent cephalopods! :-)

  36. wazza says

    one dead octopus?

    “That is not dead which may eternal lie;
    And in strange aeons, even death may die.”

  37. Samantha Vimes says

    I would have loved to see her alive and moving. Imagine the nimbleness of the small tentacles and the strength of the thick bases. Did she find ways to make them useful in her camoflage guises?

    If it is a mis-management of injury healing, perhaps the young couldn’t handle the growth demands and that’s why they didn’t survive?

  38. says

    I did, it’s true, have extra fingers
    (Alas, no memory yet lingers–
    They lopped ’em off while just a baby)
    So I was thinking, somehow, maybe,
    This octopus would never *be* bored
    As long as she could reach a keyboard,
    Blogging along with PZ Myers,
    Taking over when he retires,
    Although it may seem rather odd
    To have the Friday Cephalopod
    Referred to as “My Uncle Sid”
    Instead of just some firefly squid;
    Our cephalopolydactyl host
    Will still insult the holy ghost
    (But in those arms, the magic wafer
    might just be a little safer–
    I’d like to see the sort of priest
    Who’s man enough to face this beast!)

    On second thought, I wonder whether
    The two have ever been seen together–
    He writes those posts so awfully quick
    Perhaps he’s showing us his trick!
    P.Z.? Are those your branching arms?
    I do not mean to raise alarms,
    But really. Really, is that you?
    And if it is… Yippee! Yahoo!

  39. Torbjörn Larsson, OM says

    #27, Wow, one actually took Dick Tater Cheney’s advice.

    Ehm, wrong thread?

    The amazing thing is that we scientists have to wean ourselves from implicit telic assumptions.

    It might be easier coming from another discipline, say physics, after you get used to the pervasiveness and can excise it from the basic descriptions. As a mnemonic device for remembering to do the translation, I have started to call it “agent speak”.

    one dead octopus?

    One dead nevensexipus?