I was looking at the wikipedia article on giant squids, at

http://en.wikipedia.org/wiki/Giant_squid

and found it has a few problems. Wikipedia's whole thing is that they allow, and even encourage, people to edit the articles, but I'm not positive I qualify.

In particular, it says:


One of the more unusual aspects of giant squid (as well as some other species of large squid) is their reliance upon the light weight of ammonia in relation to seawater to maintain neutral buoyancy in their natural environment, as they lack the gas-filled swim bladder that fish use for this function; instead, they use vast numbers of tiny "statocysts" (ammonia-filled cellular structures) throughout their bodies. This makes the giant squid unfit for human consumption, although sperm whales seem to be attracted by its taste.

It's certainly using "statocyst" incorrectly, and I thought the distribution of ammonia (or ammonium chloride) was just mixed in with muscle, not in any sort of cellular structures, but I'm less sure about that... I didn't see any description of the microscopic distribution in

http://www.tonmo.com/science/public/giantsquidbuoyancy.pdf

Anyway, it might be a good public service for one of the real teuthologists to go over the wikipedia page. Probably adding http://www.tonmo.com/science/public/giantsquidfacts.php to the links section would be good, too...

I would start ranting if I wasn't so tired right now.
Pathetic job those folks are doing, isn't it? Of course, giant squid awareness isn't their top priority, eh?

-Squidman-

Monty, if you are able to identify that statocyst has been misused, you probably qualify, certainly moreso than the original author. Have at it, with a reference to the squid papers here! Those papers and the physiology forum are resource materials.

Melissa

Monty, if you are able to identify that statocyst has been misused, you probably qualify, certainly moreso than the original author. Have at it, with a reference to the squid papers here! Those papers and the physiology forum are resource materials.
Melissa

Well, I thought about it, but my concern was I don't know what the right answer is-- is the ammonia (or ammonium chloride) really distributed in little chambers (presumably called something other than statocyst)? Or is it just "dissolved" around the flesh? And what mechanism keeps the balance between sodium chloride and ammonium chloride to maintain neutral bouyancy? Is it some sort of ion pump, like in nerves? Is it neurally controlled? Is it a chemical reaction? The TONMO science article says it's not uniformly distributed, so what causes it to be inhomogeneous?

It seems like I only know enough to remove most of the paragraph... not fill in the right answer! Maybe some of that, no one knows, but I bet several people on TONMO know most of it...

Sorry folks, gotta disagree here -

You know, I wouldn't call this "pathetic" but rather a good start. The current academic shots being taken at Wikipedia belittle its main purpose; the free exchange of knowledge between interested parties. I would argue that this attack is anathema to what science is supposed to be. And there is a serious danger to simply dismissing knowledge by "non-academics".

That being said, and while I don't see too much bad information being tossed around here, please remember that this is not an established scientific journal. Being that they actually actively encourage people to write in and submit changes to observed errata, we should take full advantage of that opportunity to improve this free online database.

IN ADDITION keep this in mind: Scientific papers are not gospel either. I have seen a lot of errors in logic, methods, and observation that got through the legions of peer reviewers. If you having something "new" to add, do so. Stick it to the 'the man' if you are able.

Now... as far as the ammonium ion concentration goes, I would also disagree with the statocysts idea that the author points out. I was thinking specialized ion-storing vacuoles within the cells in the mantle, though as to which cells, I cannot suppose. Steve O's papers shed a little light on the concentration gradient across the whole animal, but not into which cells stored the ions and the mechanisms by which those ions are stored. Specialized vacuoles are generally the rule at the cellular level, though don't hold me to that, 'cause these puppies are some gnarly beasties.

Just my two cents.

John

Well, I thought about it, but my concern was I don't know what the right answer is-- is the ammonia (or ammonium chloride) really distributed in little chambers (presumably called something other than statocyst)? Or is it just "dissolved" around the flesh? And what mechanism keeps the balance between sodium chloride and ammonium chloride to maintain neutral bouyancy? Is it some sort of ion pump, like in nerves? Is it neurally controlled? Is it a chemical reaction? The TONMO science article says it's not uniformly distributed, so what causes it to be inhomogeneous?

It seems like I only know enough to remove most of the paragraph... not fill in the right answer! Maybe some of that, no one knows, but I bet several people on TONMO know most of it...

Monty,

BTW, these questions are brilliant! You rule! :read:

John

I want to echo everything John wrote above - about need for mainstream (not academic) resources, the risks of leaving the dissemination of information to academics, the fact that there are errors in academe, and the value of an engaged populace. Monty, here I really mean you and other wikipedia readers and contributors. I edit and write a lot of academic and research stuff - new blood is always needed!

I'll leave the ammonium ion questions to you who know better, like Monty and Steve and John.

Melissa

Monty,
BTW, these questions are brilliant! You rule! :read:
John

Nah. I'm just creatively ignorant... but thanks!

I'm wondering, if I had a giant squid, how I would answer some of those questions, but I'm assuming someone (likely SOS or Kat) who actually has a specimen to apply them to has thought about this a lot more than I have...

probably the right person to update the wikipedia page would have a copy of this:

Voight J.R., Portner H.O. and R.K. O'Dor 1994. A review of ammonia-mediated buoyancy in squids (Cephalopoda: Teuthoidea). Marine and Freshwater Behaviour and Physiology. 25 : pp.193-203

Weirdly, this is the only buoyancy article I got in CephBase when I searched on ammonia-- the rest were just about excretion.

Now that I've gotten a curious about it, I find that while Caltech theoretically has an online access subscription to that journal, I get a JOURNALNOTFOUND error... argh!

I want to echo everything John wrote above - about need for mainstream (not academic) resources, the risks of leaving the dissemination of information to academics, the fact that there are errors in academe, and the value of an engaged populace. Monty, here I really mean you and other wikipedia readers and contributors. I edit and write a lot of academic and research stuff - new blood is always needed!

I'll leave the ammonium ion questions to you who know better, like Monty and Steve and John.

Melissa

I certainly agree that wikipedia is a good thing, and that in general making knowledge available to the layman is a great thing... On the other hand, I have a strong personal frustration with inaccurate information in references, particularly when it's presented as undisputed fact. It seems (to me) like a lot of popular science stuff and pre-college teaching pushes things as "the whole truth" that are either wrong or incomplete, and I think this does a disservice, if not to the average public viewer, at least to the people who want to learn more, and then realize that a lot of what they learned initially turns out to be wrong.

Of course, I've had a counterpoint view from a friend of mine who is a museum exhibit science writer, who says that studies have shown that putting more than 50 words worth of info in a display drives people (or "average people" or something) away, so she feels that oversimpification is something of a necessary evil that comes with the territory. I worry that this is a case of "aiming at ONLY the average person," and that there could be a way to present things so that the average person gets it, while the non-average person can learn more details or clarification, but maybe the studies have shown somehow that this is impossible.

Anyway, I try to keep reminding myself of what I don't know as well as what I do, which probably makes me rambling and pedantic sometimes, but also makes me feel like I'm not misrepresenting much. So, I'm reluctant to put stuff I don't really know into wikipedia, even though I know the theory is that that would be self-corrected out.

But, maybe I should just edit the particular part that I know is wrong, about the statocyst, and maybe add a link to the archie and messie fact sheet... I just figured since there are real experts around, it would be doing wikipedia a service to have someone who knows more than I do check the stuff s/he would know off the top of his/her head, but I have no clue about...

Hi Monty

No one means to pressure you - it's encouragement. :wink:

Anyway, I try to keep reminding myself of what I don't know as well as what I do, which probably makes me rambling and pedantic sometimes, but also makes me feel like I'm not misrepresenting much. So, I'm reluctant to put stuff I don't really know into wikipedia, even though I know the theory is that that would be self-corrected out.

But, maybe I should just edit the particular part that I know is wrong, about the statocyst, and maybe add a link to the archie and messie fact sheet... I just figured since there are real experts around, it would be doing wikipedia a service to have someone who knows more than I do check the stuff s/he would know off the top of his/her head, but I have no clue about...

The fact that you think about what you do not know makes you an even better person to do something like this. You might not be offended when someone makes it better. "Real" experts should be happy that someone has corrected some inaccuracies - and learned from their work.

Melissa

It's certainly using "statocyst" incorrectly, and I thought the distribution of ammonia (or ammonium chloride) was just mixed in with muscle, not in any sort of cellular structures, but I'm less sure about that... I didn't see any description of the microscopic distribution in


Too true; it has two statocysts, used for balance, not buoyancy. Whether the whale is attracted to crap-tasting food is another leap - maybe that's all that's available and it just tolerates it.

Sorry, I don't know how the ammonium ions are distributed throughout the flesh/cells. We just examined ionic distribution in cubes of tissue; we didn't differentiate inter- from intracellular ionic distribution.

I reviewed something a couple of days ago that curdled my blood; a supposed 5-minute check turned into a half-day recast. It happens all of the time - there's simply too much crap online.

Too true; it has two statocysts, used for balance, not buoyancy. Whether the whale is attracted to crap-tasting food is another leap - maybe that's all that's available and it just tolerates it.

Sorry, I don't know how the ammonium ions are distributed throughout the flesh/cells. We just examined ionic distribution in cubes of tissue; we didn't differentiate inter- from intracellular ionic distribution.

I reviewed something a couple of days ago that curdled my blood; a supposed 5-minute check turned into a half-day recast. It happens all of the time - there's simply too much crap online.

Ok, well I just went ahead and did my best at an edit... mostly corrected the ammonia and statocyst bits, put "females are bigger than males" rather than vice-versa, and added a link to the fact sheet. I'd still encourage others to look at it, though, since there was plenty I was unsure about....

How did you measure the ionic distribution? Just liquify it and to some sort of spectroscopy? I can't think of an imaging technique that I know would work, but I wouldn't be too shocked if there was some stain for ammonia or ammonium chloride in histology, but on a brief google search, I didn't find one...

I also looked on google for "ammonia squid" and found that a whole lot of people reference either that wikipedia article or wherever the original statocyst quote came from, and that "experts" alternatively say the ammonia is a concentration in the muscle, or in "pockets."

I didn't look at it before, but it's neat to see it and know that a TONMO member contributed and even corrected part of it. Go Monty!

:notworth: Sir Monty !!! Good for you !
greg

... and I thought the distribution of ammonia (or ammonium chloride) was just mixed in with muscle, not in any sort of cellular structures, but I'm less sure about that... I didn't see any description of the microscopic distribution in...

This got my attention earlier, and something about it kept ringing in my head. So I spoke to my friend Thomas about the distribution of ammonium ions in this squid, and he advised me of something which I had long forgotten.

Ammonium ions in solution (NH4+) are a by-product (waste) of protein metabolism and are highly toxic. Yeah, I know - "duh"- but bear with me here. By its nature, its a weak base, and emulsifies lipids into soaps through saponification. It also does this to phospholipids (think cell walls) so accretion of this ion in the system is a bad, bad thing. So a case can easily be made for specialized, ammonium-resistant vacuoles, or the squid muscles would suffer massive reduction damage by such ions. Vacuoles would be EXTREMELY hard to detect. Maybe something chemical in the endoplasmic reticulum?

Just my two cents.

John

This got my attention earlier, and something about it kept ringing in my head. So I spoke to my friend Thomas about the distribution of ammonium ions in this squid, and he advised me of something which I had long forgotten.

Ammonium ions in solution (NH4+) are a by-product (waste) of protein metabolism and are highly toxic. Yeah, I know - "duh"- but bear with me here. By its nature, its a weak base, and emulsifies lipids into soaps through saponification. It also does this to phospholipids (think cell walls) so accretion of this ion in the system is a bad, bad thing. So a case can easily be made for specialized, ammonium-resistant vacuoles, or the squid muscles would suffer massive reduction damage by such ions. Vacuoles would be EXTREMELY hard to detect. Maybe something chemical in the endoplasmic reticulum?

Just my two cents.

John
Yeah, that certainly sounds like it would be a serious problem for cell walls, and that's fundamental enough that it's unlikely that Archi membranes evolved to somehow tolerate NH4+. So, I guess the question is scale-- are there intracellular vacuoles, or some sort of pockets lined with some protective sheath embedded in the flesh? I still also wonder how much active control there is in getting the ratios right for neutral buoyancy, too-- is there a fixed amount of "negative weight" from the ammonium chloride, or is there some active system that's moving it around (maybe it's re-routed from the excretory system into wherever it's stored?) I thought for a minute that if archi kept its density close to neutral, the squid could tense up muscles and become a little denser to sink, and relax to float, too, perhaps, but then I remembered that mollusk muscle can be thought of as a "muscular hydrostat" which conserves volume and mass, so it can't change density, just shape.... hmmmm....

Well, I would imagine that the ammonium chloride breaks down into constituent ammonium and chloride ions in solution anyway, given that NH4Cl is pretty soluble in water.

Maybe the issue is analogous to turtle anoxia. Certain turtles overwinter in ponds, and since some of these ponds freeze, the turtle is trapped underwater for some time. Given that their metabolic rates slow immensely, and gas exchange occurs through the cloaca, the major issue here is a buildup of Carbon Dioxide and resultant carbonic acid. Turtles use the bones of the shell as a "carbon sink" and therefore can tolderate several months' worth of CO2 buildup without suffocating.

Now, maybe there is an extensive mod of the Archi's excretory system that can serve as an ammonium sink. They use pretty well-developed metanephridia, but... Hmm...

Wait one second!! The major ion concentration gradient is in the mantle, right? Fish use their passive and active diffusion across their gills as a way to excrete excess ammonium and other ions, right? Do the ctenidia of Archis also serve such a function? Such a convergence with fish would not be out of the question. It just seems that continuous ion-pumping would get to be pretty metabolically costly for an animal that lives as an ambush predator. Then again, its not like its hunting gazelles on the Serengeti.

Wow, we really don't know much about these animals, do we? Gosh, as much as I hate to say this, it might be easier to find a related species, do some experiments on it, and extrapolate from that.

Just my two cents.

Sushi and Sake,

John

Well, I would imagine that the ammonium chloride breaks down into constituent ammonium and chloride ions in solution anyway, given that NH4Cl is pretty soluble in water.

Maybe the issue is analogous to turtle anoxia. Certain turtles overwinter in ponds, and since some of these ponds freeze, the turtle is trapped underwater for some time. Given that their metabolic rates slow immensely, and gas exchange occurs through the cloaca, the major issue here is a buildup of Carbon Dioxide and resultant carbonic acid. Turtles use the bones of the shell as a "carbon sink" and therefore can tolderate several months' worth of CO2 buildup without suffocating.

Now, maybe there is an extensive mod of the Archi's excretory system that can serve as an ammonium sink. They use pretty well-developed metanephridia, but... Hmm...

Wait one second!! The major ion concentration gradient is in the mantle, right? Fish use their passive and active diffusion across their gills as a way to excrete excess ammonium and other ions, right? Do the ctenidia of Archis also serve such a function? Such a convergence with fish would not be out of the question. It just seems that continuous ion-pumping would get to be pretty metabolically costly for an animal that lives as an ambush predator. Then again, its not like its hunting gazelles on the Serengeti.

Wow, we really don't know much about these animals, do we? Gosh, as much as I hate to say this, it might be easier to find a related species, do some experiments on it, and extrapolate from that.

Just my two cents.

Sushi and Sake,

John

Hmm.... this is starting to get out of my league biochemistry-wise (mortal fear of organic chem and the like is the main reason I didn't try for a double major in biology). I noticed that there are a number of papers in cephbase on the ammonia secretion mechanisms in cephs (presumably mostly the ones that don't use it for buoyancy) but I didn't look at them closely.

Wouldn't the hypothetical ammonium sink have to be distributed around the body of the squid in roughly the same distribution as Steve found the ammonia concentration, rather than being confined to the excretory apparatus? Or are you saying that perhaps the storage developed in the excretory system at first, but then a mutation allowed it to be expressed in muscle tissue (hence everywhere) and that provided the very favorable neutral buoyancy property so it caught on?

My source for thinking the ions are in the form of Ammonium Chloride (presumably in solution, as you say) is from a short mention in Wells & O'Dor "Jet Propulsion and the Evolution of the Cephalopods" from Bull Marine Science 49(1-2):419-432 1991:

Where coleoids have, for one reason or another, returned to life-styles that would benefit from neutral buoyancy, they have generally achieved this by replacing sodium with ammonium chloride, a mechanism that leads to rather flabby animals but which, unlike the gas-filled shell, is not limited by implosion depth (Clarke et. al. 1979).


Clarke et. al. sounds like it may be similarly enlightening to the journal that's missing its online form:

Clarke, Denton, and Gilpin-Brown, "On the use of ammonium for buoyancy in squids," J. Mar. Biol. Ass. U.K.: 59 259-276

Weirdly, it's not in cephbase. It's also not in the Caltech or U of California library systems database (the whole journal, in fact!). Steve refers to it in his archi buoyancy article in the TONMO science section, too.

So I guess people have studied this, but only published it in hard-to-find places...

Weirdly, it's not in cephbase. It's also not in the Caltech or U of California library systems database (the whole journal, in fact!). Steve refers to it in his archi buoyancy article in the TONMO science section, too.

... a long time ago I was approached and asked to submit hard copies of my papers to cephbase; I didn't as I was led to believe that they only cite articles that they have a copy of (or some such thing) online. I thought that a little rank. Accordingly countless squillions of papers are not cited on cephbase, simply because they haven't got copies in a personal library!!

I don't think that that is an appropriate service; I thought it more a means of freely developing a library for a limited few.

"There are now ~5900 ceph papers in our reference database, including 33 papers published in 2004, 119 papers published in 2003, 161 papers published in 2002 and 1103 references in pdf format, available for download. Currently, we are only able to sporadically enter new papers into the database. Please send reprints to Catriona Day, Fisheries Centre, Lower Mall Research Station, 2259 Lower Mall, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4 and email pdfs to cephbase @ hotmail.com. Reprints and pdfs we receive will be added to CephBase in time but there may be considerable delays. Thank you for your patience."

This is helpful-- I guess for some squids (not specificially architeuthis) there are vacuoles in the muscle mass (there's an overview in the introduction...)

http://academic.evergreen.edu/t/thuesene/seibeletal2004.pdf

Monty,

You're preaching to the choir about orgainic chem. :wink: Personally, I didn't like the course because most teachers don't seem to like teaching it. And its relevance to modern biology is treated as nearly nil, when the exact opposite is true. But as a subject, its bloody brilliant and fascinating.

Anyway, I figured ontogeny would be a factor here. Steve-O indicated that giant squid were found at different levels of the water column at different stages of their lives, so it would make sense that whatever triggers the storage of ammonium in the system (regardless of structures) occurs as the squid develops.

The quote by Clarke et al made me wonder; if ammonium ions are used in place of sodium, in which functions are they replaced? Also, ammonium ions are 18 amu's (atomic mass units), while sodium are 23 amu's. Are five amu's really enough to affect neutral buoyancy? Maybe there's a chemical property in how the ammonium ions are used as well as their weights. Considering that ammonium ions and hydroxide ions (OH-) form a weak base, while sodium is a reactive metal (and strong base when fused with free hydroxide), there would be a markedly different reaction when these are utilized by a living system. I have to read these papers. However, what do they mean by "mechanism" which "leads to flabby bodies"? Molluscs are soft-bodied by nature! Its a main feature of the phylum! I need to read this paper before I make any generalization or conclusion, but this phrasing was a little odd.

So, Steve... Sound like any good project ideas?

John

Okay, went back to my physio. textbook and checked some info.

AMMONIA (NH3) is a metabolic waste compound produced in most marine invertebrates. Nasty stuff there; it passes easily through cell membranes and is highly toxic to cells. However, when presented with a free proton (H+), it becomes the ion NH4+, or ammonium. This is called diffusion trapping. Cell membranes use charged protein "gates", which repel ammonium to a cerain degree. However, ammonium ions are still toxic and must be either excreted as ammonia through changing ammonium to ammonia, amination (the act of adding an amine to the ammonuim ion), or by storage. The first two are metabolically costly processes. The last is storage by conversion to a less toxic, more easily stored material like glutamine. Fish do this.

Ammonium, while being less toxic, still affects neurotransmission at the postsynaptic level. Ammonia is deadly and must be excreted. Hmm...

Maybe this also has to do with the pressure and properties of water at the midwater levels. Ammonium excretion is an active process, and maybe its a lot harder to excrete ammonium and ammonia in the depths at which the adults live, so subsequent buoyancy my have evolved as a side-effect of the need for ammonium storage. Such a welcome mutation could have been the cause of the Archi's lifestyle. Who knows?

John

... we don't know if the subadults/juveniles are ammoniacal.

Ammonium, while being less toxic, still affects neurotransmission at the postsynaptic level. Ammonia is deadly and must be excreted. Hmm...
Hmm...is right, John. Don't squid axons have some odd ability to neutralize "nerve gas" compounds? The de-toxifying agent is an ion called isethionate, (good thing I had the Ellis book out for crypto-zoo references, as he's also got a section about the odd enzyme), "an alcohol molecule with sulfonic acid at one end." Would isethionate react with ammonium in any meaningful way?

Clem

Would isethionate react with ammonium in any meaningful way?

Clem

I don't think so, given that acids donate protons and adding another H+ to NH4+ would be HARD.

What are the coping mechanisms for other ammoniac squid? Are there some that we haven't mentioned yet?

John

It is my contention that this sentence from
http://en.wikipedia.org/wiki/Giant_squid
is complete nonsense:
However, it is thought to be impossible for a giant squid to lift its tentacles from the water.

Since I removed it once, and one of the editors put it back, I'd like to get confirmation from you architeuthologists that it's pretty bogus. Of course, since Architeuthis is generally not at the surface at all, and no one has seen it alive and healthy, there's no way to know this, but from what I know about cephalopods, they're pretty strong in general, and only the most gelatinous of deep-water cephs seem like candidates for not being able to lift their own arms without help from bouyancy.

Obviously, I'm pretty sure about this, I just would like "ammo" from known experts to wave in the face of the Wikipedia editors if they re-insert this silliness.

(they also seem to be very attached to the many-species-of-architeuthis taxonomic view, but I have references documenting the controversy of that.)

Thanks

- M

Wiki's been under fire from the Slashdot community recently (and probably several other communties) for their careless attitude toward user privacy and security. They had posted a list (that they have since removed) of users whose password hash values were identical to those of known trolls and problem users. Brilliant. They might as well have come right out and given their users' passwords to the bad guys. I'd change my wiki account password pretty soon if I were you.

Wiki's been under fire from the Slashdot community recently (and probably several other communties) for their careless attitude toward user privacy and security. They had posted a list (that they have since removed) of users whose password hash values were identical to those of known trolls and problem users. Brilliant. They might as well have come right out and given their users' passwords to the bad guys. I'd change my wiki account password pretty soon if I were you.

Well, I checked that I wasn't on that list, but yeah, I guess. I doubt there are any nefarious people who care about my wiki password anyway, though, since I'm not much of a contributor and there's no useful personal or financial data associated with it. In fact, I did my first edit of the giant squid thing as an anonymous user, but I figured I'd make an account so I can actually post justifying my edits.

Thanks for the heads-up, though. Slashdot is sometimes a bit, er, polarized, of course-- they have a love/hate relationship with wikipedia, it seems. The whole wikipedia thing is sort of goofy, because there's not a formal system of fact checking, but it's pretty good for quick fact-checks as long as you keep in mind that it's only about 80% likely to be accurate.

Slashdot is sometimes a bit, er, polarized, of course-- they have a love/hate relationship with wikipedia, it seems.

:lol: You can go even furhter and say they're a bunch of egomaniacs looking for a good flame war, but if they're concerned about something, it's usually something pretty scary.

Hello Monty,

Regarding the ability/inability of Archie to lift its tentacles above the water, I recall some discussion about it here at TONMO, and it was suggested that the animal may be able to lift them above the surface if they were in their "zipped" configuration. (Can't remember who said that. It might have been me, for all I know, and I don't qualify as an expert.) Archie's tentacles aren't particularly muscular, and are extremely flabby when the animal is dead; a moribund, weak Archie at the surface would have a hard time lifting these appendages. Then again, it should be noted that the classic sea serpent profile, presenting an undulating series of partially exposed coils with a "head" peeking above the surface, might be within an Archie's ability to project, since roughly half of the conjoined tentacles' length would still be underwater.

That's all I have to say on that matter, and would have left it at that, but I just had to do a Google search for "Achiteuthis tentacles, strength," and found this PDF, ( http://www.zoology.ubc.ca/~biol438/Reports/Squid.PDF.) written by David Chung of the University of British Columbia. I can't judge the mathematics deployed, but the physical data, measurements, etc. seem very incomplete. If the maths were applied to a more accurate model, what would the results be? Cool stuff, and Mr. Chung is to be commended for tackling this slightly gonzo project. It may not be decisive, but it should be enough to qualify that Wiki line.

I just noticed Wiki's statement that the sperm whale and the sleeper shark are the only known predators of Architeuthis. That's only partially true, as juvenile Architeuthis specimens have been recovered from lancetfish and albatross stomachs, and there are reports of specimens recovered from billfish and sharks. The sperm whale and sleeper shark may be the only known predators of mature Architeuthis.

Cheers,
Clem

:lol: You can go even furhter and say they're a bunch of egomaniacs looking for a good flame war, but if they're concerned about something, it's usually something pretty scary.

Except when it's not:
http://it.slashdot.org/it/05/05/30/1111206.shtml?tid=128&tid=106

Hello Monty,

Regarding the ability/inability of Archie to lift its tentacles above the water, I recall some discussion about it here at TONMO, and it was suggested that the animal may be able to lift them above the surface if they were in their "zipped" configuration. (Can't remember who said that. It might have been me, for all I know, and I don't qualify as an expert.) Archie's tentacles aren't particularly muscular, and are extremely flabby when the animal is dead; a moribund, weak Archie at the surface would have a hard time lifting these appendages. Then again, it should be noted that the classic sea serpent profile, presenting an undulating series of partially exposed coils with a "head" peeking above the surface, might be within an Archie's ability to project, since roughly half of the conjoined tentacles' length would still be underwater.

That's all I have to say on that matter, and would have left it at that, but I just had to do a Google search for "Achiteuthis tentacles, strength," and found this PDF, ( http://www.zoology.ubc.ca/~biol438/Reports/Squid.PDF.) written by David Chung of the University of British Columbia. I can't judge the mathematics deployed, but the physical data, measurements, etc. seem very incomplete. If the maths were applied to a more accurate model, what would the results be? Cool stuff, and Mr. Chung is to be commended for tackling this slightly gonzo project. It may not be decisive, but it should be enough to qualify that Wiki line.

I just noticed Wiki's statement that the sperm whale and the sleeper shark are the only known predators of Architeuthis. That's only partially true, as juvenile Architeuthis specimens have been recovered from lancetfish and albatross stomachs, and there are reports of specimens recovered from billfish and sharks. The sperm whale and sleeper shark may be the only known predators of mature Architeuthis.

Cheers,
Clem

Yeah, the predator thing is reasonable. I think the pdf article is full of silly assumptions... I assume Archi tentacles are roughly the same muscle profile as those Kier describes in a number of papers, which definitiely do not have a central tube of 1/3R of fluid-- they're amost all muscle. Also, who cares if they can hold them statically at 45 degrees, when the normal operation of squid attacks is to shoot them out rapidly? So, I think the paper is interesting, but rather questionable. On the other hand, I don't have a better counterargument than "that's silly," and it certainly does seem like Archi attacks more through stealthy sneak-and-grab fishing than muscle power... maybe I should just leave it be. I know the ammoniacal squids are supposed to have weaker muscle per volume than other cephs, but I'm still skeptical. Maybe I should combine that pdf paper with some of the info in Kier's papers on this kind of stuff, and see if I get the same answer (in my copious free time).

It's probably silly to pursue this too far, anyway, since regardless of archi's ability to lift its arms out of water, I think it's accurate to say that all evidence points to a lifestyle that would be quite incompatible with attacking a ship, which is their point. :razz:

another dubious-sounding thing has appeared on the wikipedia giant squid page:

male giant squid are equipped with a prehensile spermataphore-depositing tube, or Hectocotylus, of over 90 cm (three feet) in length, which extends from inside the animal's mantle and apparently is used to inject sperm-containing packets into the female squid's arms

Unless I'm mistaken, a hectocotylus always refers to a modified arm of a ceph, while I believe the organ referred to in architeuthis is generally known as a penis, and is not related to the arms at all. Could one of you anatomical teuthologists verify or refute this, so I can make the appropriate edit, please?

(never mind, I confirmed that I was correct in the Architeuthis Reproduction article, thanks!)