Architeuthis and Mesonychoteuthis questions

Discussion in 'Physiology and Biology' started by Nik, Apr 6, 2005.

  1. Nik

    Nik Blue Ring Registered

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    Hey all,

    Right then. For those who don’t know, I’m working on a series for the BBC and Discovery about the deep ocean and I’ve been here a while, learning everything I can to make our CGI squid the best they can be. I’ve learned a great deal from all the fantastic posters her already, but now I’m at the next stage in the production process and I’m asking for help again. The sculpts of the Architeuthis and Mesonychoteuthis for the series are complete and with our computer graphics people for the lasers and the scanning and the rest of the stuff they do, and I’ve now got the job of getting the texture/movement references together. I think I’ll just throw these questions out there and see what everyone thinks. If anyone wants to make a stab at an answer, I’m all ears.

    a) colouration – In fact, we won’t see the colour of the squid very much as they’re going to be at depth with no colour visible, however, for accuracy it would be good to know whether archie and the big guy are all one colour (red and darker red) or whether they have any variation in markings. For example, I remember in one of the live archie photos that were posted, it seemed to have red on top and white underneath (for disguise against the sky?). Also, I’ve not read anything about chromatophores for either species so I’m assuming they can’t flash colours – too deep for this anyway?

    b) hunting posture – and hunting in general. I’m going for the idea that Architeuthis hangs pretty stationary in the water at around a 45° angle with tentacles hanging pretty much vertically down, locked together and with the tentacle clubs open – does this sound right, or have there been some more thoughts on this? In mesonychoteuthis’ case I really have no idea. I’m guessing it’s more of an active hunter and could actually extend its tentacles to seize its prey, but that’s a guess. Also, is it going to be horizontal in the water, or at an angle?

    c) photophores/ink – I know mesonychoteuthis has a couple of photophores near its eyes, what are these for, hunting illumination, attracting prey? I believe Architeuthis has none, is this right? Ink would seem to be pretty pointless down at those depths, unless it was bioluminescent, and I doubt it would really help either species avoid predation from something hunting by echolocation, so I’m guessing they have none?

    d) keels – Architeuthis (I believe) has keels on its third arms – would these be most prominent during jetting and lunging or apparent the rest of the time?

    Phew, that’ll do for now. Sorry for asking all these questions, but you guys are the best, so I may as well get the best answer. I’ve been back through the old topics and got what I can, but I was missing a few things. There’ll probably be a few more things that come up, but any answers, musings or other insights on these topics would be greatly appreciated. :smile:

    Cheers

    Nik
     
  2. Clem

    Clem Architeuthis Supporter Registered

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    Hello Nik,

    I'm not one of the true experts, but I'll take a crack at responding to some of your questions:

    Archie does have chromatophores, and, judging from those pics of the living article, is definitely capable of color shifting; whether it can flash or not is difficult to say. (Click here to link to the living Architeuthis photos) Some of that Japanese specimen's skin was rubbed off, presumably during the capture and tow into the rockpool, which accounts for some of the whiteness. On the other hand, the sequence of smaller photos does show changes in colour on the arms and head. Impossible to say if this was stress-induced, a sign of impending death or a reaction to the flash photography. As for the notion that Archie might adopt a white ventral face as a form of counter-illumination, it supposes that the squid spends some time close to the surface during daylight hours. It might do this at some stage of its development, but I believe the jury is still out.

    Chroma-shifting would be valuable down in the dark, though the color matters less than the tone, i.e. maintaining a brightness value consistent with the surroundings. This would be a useful ability if Archie were backlit by a cloud of luminescent organisms, or at the lower reaches of downwelling light. There are other predators to worry about besides cetaceans - some big pinnipeds, sharks and billfish - and they do use their vision to hunt.

    Mesonychoteuthis has photophores on the ventral margin of each eye, and photophores in the mantle cavity...on the gut, I believe. How Messie uses its blinkers, I don't know. It might be part of predatory behavior, or a means to attract a mate. There's no evidence that Archie has photophores. As for inking, that's a good question. Messie is a cranchiid squid, and I know there's at least one cranchiid squid, Cranchia scabra, that inks into the mantle cavity, rendering its transparent body effectively opaque. Dr. O'Shea reported that the mantle lining of the necroscopied sub-adult Mesonychoteuthis was stained black.

    Archies have ink-sacs that are relatively small, but they do have them. A mature Architeuthis living way down deep probably wouldn't need to ink, it's useless against echo-locating predators, as you say, but a small, young Architeuthis might very well need to ink, if it spent time near the surface. I don't know if the paralarval Archies have functioning ink-sacs.

    When may we see the results of your work? Sounds like spectacular stuff.

    Cheers,

    Clem
     
  3. Steve O'Shea

    Steve O'Shea Colossal Squid Supporter

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    :shock:

    They definitely both have chromatophores, so will be capable of the colour change. The juveniles of both occur in the shallows, and would therefore need the ability to 'disappear' or change colour to avoid whatever predator was out there. Adults probably retain this ability, even though at greater depth it might appear a somewhat redundant character.

    Spot on; this will be VERY nice to see!!

    Take my word on this for the time being, but have the mantle on the horizontal and the arms oriented vertically, up . Why, well, I'll tell you in pm, rather than online (sehkrit theory - a lot of work to do on this yet)

    Archi could well have a photophore on the end of its ink sac, but this has not been reported in the literature (rendering it even more similar to onychoteuthid squid than traditionally believed). It has no photophores on the mantle, head or arms.

    Mesonychoteuthis has two photophores on the underside of the eyes. No, not to hunt or attract prey, but more likely to avoid predators. The entire body of this thing is basically transparent/translucent, but the eyes are anything but (see attached image - a related beast, Teuthowenia pellucida) - they're chunky, extremely obvious structures. Picture yourself, a predator below looking upwards at the squid; the eyes would stand out (silhouetted) in stark contrast to the lighter sky; the photophores are thought to compensate for this by beaming down a little light to mirror that coming from above, thus rendering the solid eye invisible relative to the sea surface. That's the theory anyway. For the same reason (general transluscence), the digestive gland is oriented on the vertical axis, rather than antero-posterior (horizontal) axis of the mantle; consequently the silhouette (from below) is minimised; like the eye it also has a photophore there to conceal it from below.

    You ask really good questions!!!!! Most prominent during jetting and lunging.

    Ps, re the attached image of the related cranchiid, Teuthowenia, DO NOT WORRY about the arms being oriented directly DOWN; we have good reason to believe that the opposite is true for Mesonychoteuthis.

    .... What's the title of this? Have I got to ask a few of my contacts what's up?
     

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  4. Nik

    Nik Blue Ring Registered

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    Wow, thanks Clem and Steve, some great stuff there - lots for me to think about!

    The series only has a working title for the moment so i can't tell you what it will finally be called, because I don't know.... What I do know is that it's scheduled for transmission some time in early summer next year on BBC and some time later in the year on Discovery, although I'm not sure when. It's also going to be on domestic TV in Germany and possibly some other places, although that's all still in discussion. I would attach some photos of the two macquettes we have for the squid, but a) I don't have them, they're with the graphics people and b) I probably shouldn't, confidentiality and all that. :roll:

    The whole colour shifting thing is interesting - i really didn't expect that both species would have that ability. It would be good if I could use that in the series somewhere, any suggestions when either of these guys would actually flash, perhaps as a last resport if they're about to be eaten? Also, if mesonychoteuthis is pretty much transparent, what about archi?

    I did actually use the pictures of Teuthowenia when I was briefing the sculptors for the Messie model, to get that whole bug-eyed look about him, but tentacles held up :shock: that's a new one. Steve, i'll PM you about this.

    While we're on the whole tentacle position business, if Architeuthis has its tentacles down, are the arms going to be together while it waits for prey or more open? I guess if it wants to use its keels the arms have to be together for the lunge and then open up when it nears its prey, but how would it be during the wait for prey?

    Again, thanks so much for your answers. I’m hoping to make these squid sequences the best that have ever been seen and as close to what we think really goes on as possible so all this is dynamite stuff. :grin:

    Nik
     
  5. cbarela

    cbarela Blue Ring Registered

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    Steve wrote "The entire body of this thing is basically transparent/translucent"
    Did I read that right?!?! You're saying that monster, Mesonychoteuthis, is nearly invisible when alive? And when it dies it turns white/red? Please explain!
    I am working on an illustration of one of these and that would be completely useful. -Chris
     
  6. monty

    monty Colossal Squid Staff Member Supporter

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    another thread about modeling CGI architeuthis

    Just to make sure, you've seen this, right?

    http://www.tonmo.com/community/index.php?threads/2850/

    Also, just out of professional curiosity, what software are you using for the animation? I'm a computer graphics researcher, but the lab I work with has generally made its own software, so I'm curious about what commercial software products people like. I'm starting to learn Maya, but I haven't seen evidence that its dynamics and deformable body features would be well-suited to cephalopods.

    I've actually though that there is potential for interesting research in making computer graphics objects based on cephalopod musculature. I had a brief stint of sticking things into an MRI machine and extracting the geometry, and I tried to get the folks I was doing that for to let me do some diffusion-tensor studies of ceph muscles to get a good geometric model of the muscle fiber layouts (unfortunately, they were more interested in mouse spinal cords, so I couldn't get time to do it-- imaging diffusion data takes many hours). William Kier (http://www.bio.unc.edu/faculty/kier/) has done a lot of inspirational work in how the "muscular hydrostat" nature of cephalopods explain the motions that they go through, but I think that most standard computer graphics deformations don't correspond very well to this, and so I would expect it to be very hard to make a system like Maya make realistic animations of cephs without a lot of hand-tweaking (I know a lot of Pixar animators fall back to "a keyframe every frame" for some motions, even though they employ many of the best dynamics people in the computer graphics community).

    Anyway, I look forward to seeing the animations in your show! (Although I reserve the right to be a dynamics snob-- I thought, for example, that the still frames of dinousaurs in Jurassic Park looked fine, but when they moved, a lot of them had motion that looked more like inflatable parade balloons than, say, like elephants...)
     
  7. Steve O'Shea

    Steve O'Shea Colossal Squid Supporter

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    Heavens; I seem to have bitten off a bit here ....

    Chris, look at the earlier pic of Teuthowenia, and then look at this one, post mortem.

    Not all squid are likely to be translucent/transparent, but many are certainly capable of this; I think that the majority of species would lose the ability to go completely translucent with maturity (and bulk), but it's still cool to think that they have this ability (and until we know otherwise, they probably do retain partial ability).

    Post-mortem Teuthowenia , the two lower images, and post-mortem Chiroteuthis (upper right) attached (don't they look disgusting!); also live Chiroteuthis (second attachment). The upper three images (LHS) are of a new species of Sepioloidea.
     

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  8. Steve O'Shea

    Steve O'Shea Colossal Squid Supporter

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    Hi Nik. I'm waiting on some horrendously fast, trillion-frame-a-second imagery to turn up on my doorstep (it was done for Discovery, for the AFO series on the Mesonychoteuthis/sperm whale battle). Given the long-standing association between BBC/Discovery, and the fact that the imagery was taken by Discovery C (and to the best of my knowledge has never been used), you should be able to get access to this (it will certainly help you interpret what is going on in that trillionth of a second lunge forward to restrain prey).

    Re Archi translucence ..... hmmmm .....I would so dearly love to say 'yes'. Certainly the juveniles are capable.

    Re feeding. There's a heck of a lot more to this than the arms simply being held together prior to a lunge, but I'll not ramble until I've got some schematics to post online. I'm taking a little time off this weekend, so will sit down and get them drawn up and posted here.
     
  9. monty

    monty Colossal Squid Staff Member Supporter

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    Architeuthis color

    Actually, this thread reminds me of a completely unsubstantiated idea I had about architeuthis coloration-- I'm curious if it may be plausible or if it's silly for some reason I haven't thought of:

    I've noticed that most pix of archis show them as red. I know that at depth, red is the first sunlight color to get filtered out (and in fact, I carry a small dive light in even in non-night-dives, and find that a lot of "stuff" underwater looks very differnt in its full-spectrum light from how it looks in the blue-green sunlight, and that's only at around 30 feet depth).

    So, I was thinking, something that reflects red light (but not blue and green) will look pretty much black in the inky depths. However, architeuthis has HUGE eyes, so it can presumably pick up very small amounts of light. From what I've read, it's not believed that cephs can discriminate colors, but maybe they are sensitive enough to the small amount of red light that they can see others of their species (for communication, mating, or what have you) even though they look black (hence invisible) to most of the other smaller-eyed critters (snacks) at that depth.

    It seems like a no-brainer that they would take advantage of the huge eyes to spot prey from outside of the prey's perception, and just snag them before they even notice, and that seems very consistent with the "float and lurk" hunting practices that are hypothesized. This also goes to explain why they're never seen on submersible video-- they can see the sub's lights from far away, and avoid them.

    What's the color distribution of chromataphores in Architeuthis? I know some commonly studied species (I think sepia officianalis?) has sort of layers of black, brown, yellow, then the leukophores(sp?)... I don't know about red, but clearly octopi that turn red when they get mad have red chromatophores, right? Do O. Rubescens (sp?) have red skin, or a lot of red chromatophores?

    Anyway, the main idea was that red would be visible to other archis but not to most things living at that depth with less huge eyes...
     
  10. monty

    monty Colossal Squid Staff Member Supporter

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    for a smaller squid (Loligo pealei) there's this high-speed feeding picture, but it's not clear how well it might apply to big ones... It seems like squids and cuttles in general have a lot of evolution behind the tentacles being able to reach out very quickly for a strike, though:

    http://www.bio.unc.edu/faculty/kier/squid.mpg
     
  11. Steve O'Shea

    Steve O'Shea Colossal Squid Supporter

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    Time to duck for cover for the day, but just one more post (and image).

    If you were to look at the animal head on, and have two tentacles dangling down, this is pretty much what you would see (I believe!!). It's not an animal with a circlet of arms in a tube around the head, but the arm crown is dorso-ventrally compressed/laterally exaggerated .... Note the alignment of the keels (usually called swimming keels) and the eyes; the animal peers down this keel and sights up prey at distance (with all of the arms held together), like gun sights. The prey moves, and so too does the tip of all the arms, and the eyes track all of this down the keels; the prey moves, the squids arms track it, the fins adjust the position of the squid in the water column and once again the squid will be oriented directly in front of the prey item. As such, these swimming keels have a secondary function in prey capture.

    The left image is of broad squid, Sepioteuthis australis, an adult, and was taken by Felipe Gomez here at AUT. In Architeuthis the keels will not be so pronounced, but they are present all the same. There are so many more pics, but it will have to wait until the weekend.

    The two right images are of paralarval Sepioteuthis, albeit one with a fish in the arms. You still get the picture, where the arms are extended out and the very tip serves to track other prey (or in this case, possible assassin, or food thief); I've got images somewhere of these squid doing this as they sight up on a prey item; at rest you'll see that the arms are somewhat all over the place.
     

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  12. Clem

    Clem Architeuthis Supporter Registered

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    Hello Monty,

    Different strokes for different squid, maybe, but it's odd that some benthic squid, like the chiroteuthid Nik posted a link to (elsewhere in this forum), show no great alarm at the presence of ROV's putting out lots of illumination, and even approach the light source I'd expect those benthic animals to be even more perturbed by bright lights than mid-water dwellers. If the lights aren't spooking lurking Architeuthis, their absence from video records might reflect the tight spatial parameters of most deep-sea exploration, often little more than an underwater elevator ride.

    VERY interesting thoughts about red light and skin color...I'm scratching my head. Do you know of any ocean dwellers that have an equivalent ability to detect available red light?

    Cheers,

    Clem
     
  13. monty

    monty Colossal Squid Staff Member Supporter

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    Yeah, certainly some squid are known to be attracted to lights-- don't squid fishing boats use lights to attract them? I could easily imagine that architeuthis is very comfortable in the dark, where the big eyes give a big advantage, but, hey, I can imagine an awful lot of things. I would expect that there could be some critters that live in the dark so much that their pupils can't constrict down far enough to deal with bright lights, so the light could make them uncomfortable. I don't know how dynamic archi pupils are... I've always been struck by the vampyroteuthis eyes in the pix the MBARI sub took-- it looks like a puppy!

    I saw a link (I think on TONMO) about a project using infra-red illumination and an infra-red camera catch critters attracted to a fake "glowing jellyfish" lure. That seems useful on the theory that most sea creatures wouldn't be inclined to see infrared or red light, since it's not really present in their environment... I'll be interested to see if they get more good results from their project. I wonder if they've thought about setting up the IR camera and lights and a visible light setup in the same environment, and taking a survey of what numbers of various critters they see-- then we could find out how much difference there is in what critters like or dislike visible light....

    It might also be neat to build a camera for a submersible that is similar to an architeuthis eye-- really big aperture, and very sensitive CCD-- maybe they could use an astronomy-oriented CCD (or other photosensor). Then, just drive the sub around without lights at all, and see what you can see with the sparse natural light.

    I don't really know in general, but from a teleological evolution view, they shouldn't-- if there's not much red light, then evolution would tend to push them in the direction of being sensitive to the more blue ranges. On the other hand, critters that evolved their eyes in the shallows and then migrated to the depths might not have much evolutionary pressure to lose the red vision, and I guess it's generally believed that the cephs were driven deep by the rise of the bony fishes, so there may be some conserved eye features from when they hung out more in the shallows. I imagine that since some octopi like to be red to make a stand-out display, they can probably see red light as well, but they stayed in the shallow water and competed with the fish...

    Color vision is a little funny to measure, in that we have preconceptions about it-- we have 3 cones (red, green, blue) and rods that just have a wide frequency response, but many creatures just have one type of receptor, so they essentailly see in black and white (we can get some idea of how they perceive the world by night-time, when our cones don't work well and we rely on our monochromatic cones.

    However, other critters have very different arrangements: there is some shrimp that has a large number (maybe 11) different cones (or cone equivalents) so they can distinguish spectra in some very different way than we perceive color. In fact, the "Red/Green/Blue" or "Red/Yellow/Blue" color classification is more of an artifact of our physiology than anything to do with the spectrum... I expect this biases our perceptions of how and why various things evolved various color patterns a lot (flowers, bird feathers, and butterflies come to mind).

    I also know that new world monkeys and old world monkeys have different color vision... I think one of them doesn't discriminate between red and green, but it may be that one doesn't have blue cones... I'm pretty sure it's the former, though-- blue cones are very different genetically than red/green, and in fact have their dna parts on a different chromosome, while red and green only split from each other recently... this partially explains why red/green color blindness is a lot more common than other kinds. I think the red/green cones are on the X chromosome, which is why men are much more often colorblind than women, 'cause they don't have a redundant copy.

    Anyway, I think the shrimps I mentioned have most of their spectral discrimination in the blue,green, and UV, which makes sense given the light that gets to them (but I don't know/remember the species of shrip, or at what depth it lives, and if it's nocturnal, etc.).

    I have no idea what the frequency responses of the visual pigments are in most marine critters, though; just these examples. I took a course in vision, focusing on neurobiology, but it was really all about vertebrates, and mostly cats, monkeys, and humans.
     
  14. Squidman

    Squidman Vampyroteuthis Registered

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    This is the thread I've been waiting for for fourteen years! What is this "sehkrit theory" business, Steve? I seem to be the only person here curious about it.

    People at school think I am strange!
    -Squidman-

    P.S. Where can I get good squid literature? I have had many recommendations on WHAT to read; I just don't know where to get it.
     
  15. Nik

    Nik Blue Ring Registered

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    Now it starts to get juicy! Monty, i've seen the Loligo pealei attack sequence and I love the symmetry of the arms, just amazing - I'd love to be able to show archi doing something like this but i'll wait and see what Dr O'S has from Discovery. I'm the Associate Producer of the series so i oversee a lot of the production and research but the graphics are done by a post production company that we have a long standing relationship with so i won't personally get involved in putting the CG models together. Next time I speak to the animators i'll try and find out what software/hardware they're using. :smile:

    Steve, I'm pretty sure we have access to any Discovery archive we want, so i'll check that out, thanks.

    Clem, i know that the Dragonfish, Malacosteus niger, Aristostomias sp. and Pachystomias microdon have red photophores under their eyes, supposedly to illuminate their prey - and naturally have the appropriate pigments to sense the same wavelength they're emitting. Presumably this would also give them the ability to see and avoid a red predator, provided it was illuminated.

    Great to see all these posts. Thanks everyone.

    Nik
     
  16. Squidman

    Squidman Vampyroteuthis Registered

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    This is possibly the best thread I have ever read. Seriously.
     
  17. um...

    um... Architeuthis Supporter

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    Nope. I was thinking about PMing the crap out of him until he told me, too.

    Specifically?
     
  18. um...

    um... Architeuthis Supporter

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  19. Steve O'Shea

    Steve O'Shea Colossal Squid Supporter

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    The 'sehkrit theory' is something Kat and I have chatted about on and off for the past couple of years. There's not enough evidence to support it right now. It's quite exciting stuff; one of these days when time is freed up we might just get around to doing something about it.

    We'll spill the beans if Ummmm... posts his pic on the 'Meet the Staff' page.
     
  20. um...

    um... Architeuthis Supporter

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    I think I'd need to be the webmaster in order to do that. Nah, I'm pretty sure that a barrage of PMs is the best way to go.
     

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