According to the community calendar, today is the big day for Steve and Kat! They are having their colossal squid necropsy today in Wellington, NZ, together with the Discovery Canada filming crew. Hmm... they probably have to sign NDAs, assuming Discovery will want to air the footage... but whatever, tell us what you can! The calendar entry promises some photos... we're ready! :wink:

Saw it on the TVNZ news on Friday night! What fun!!!!!! Even got in ahead of the sports news! :notworth:

Can either Steve or Kat tell me? Is the inner mantle really black?? Or was it ink? or an artifact of filming?

J

The inside of that mantle was rather weird Jean - I've never seen anything like it before. It most certainly was black/purple. We made one incision and then ...... my word ..... time to walk away and have a good think about things. The anatomy is quite unlike anything I've seen before.

Have to do more work (research/comparative anatomy) on that beast before having another look at it.

The inside of that mantle was rather weird Jean - I've never seen anything like it before... We made one incision and then ...... my word ..... time to walk away and have a good think about things... The anatomy is quite unlike anything I've seen before...


Grrrrrrr...

Sorry Clem, the intention is not to draw this out. There were two different camera crews on us at the time (long story); you have to be so careful under this sort of pressure not to say anything that you would regret later, and certainly not to make incisions everywhere in the body of the animal to try and figure things out in a hurry (once cut, the integrity of the animal is destroyed). It is a slow job figuring these things out.
Cheers
O

Steve,

Yes, yes, yes, I know. However, if you really don't intend to draw things...out, then...my lord...you shouldn't...do...this...

:wink:

Clem

I wonder, our colossal friend is a predator right? so maybe the dark colouration is a camouflage thing. I just wonder this because many deepwater fish have black linings to the mouth and oesophagus and the thought is that it is black to aid in ambushing prey. When I watch squid and octis as they open the mantle to take in water you get a flash of the pale inner lining, not good if you're hanging in the pitch black waiting for a toothfish to swim by........ an idea anyhow


What was that about it defaecating into the gills :yuck:

what a totally weird thing, most other squid I've seen (not that I've seen as many as our resident guru but I've seen a few!!) defaecate into the funnel and so to outside!

j

The anus opened very posterior on the surface of the digestive gland; I really wasn't prepared for that (quite some distance from the funnel). The gills had quite a remarkable structure; more work required. The nidamental glands were positioned on the lateral face of the digestive gland, dorsal to the gills (instead of along the central, ventral mid-line); they also had rather fleshy lips, reflected anteriorly over the point where the gills insert onto the visceral mass (as if the reproductive tissue had been rotated dorsally, to lie atop the digestive gland). More work required; I am uncomfortable mentioning this much.
Cheers
O

Photos to come though... ;)

Yes, yes, yes, I know. However, if you really don't intend to draw things...out, then...my lord...you shouldn't...do...this...
Clem

is that out of frustration, or were you trying for a capt. kirk impression?


:cthulhu: :heart: :beer:

WK,

The Shatnerian resonance was unintentional. Dr. Steve likes to build suspense with the liberal use of...tantalizing fragments...separated by...three periods. It has a 2001 "My God...it's full of stars..." quality about it.

:heee:

Clem

...that might be true, but it is ... ummm ... unintentional :)

Having said that, did I tell you about the ... hold on ... would love to tell you but it might be ... hmmmm ... premature to do so. Maybe tomorrow. Really would love to spill the beans now ... but ... you know. :wink: ... have to have something to post tomorrow

Dear all

I am very new to this site, and this is my first post, so please forgive me if I'm going over old ground.



A dormant interest in cephs. being reawakened by the recent reports in the media on [i]Mesonychoteuthis, I was very glad to find this website, and also the Tree of Life website.

From Kat Bolstad's article on "Deep Sea Cephalopods" on this site, I learn that the gut of Architeuthis dux has a maximum relaxed diameter of only 10mm. Is the implication here that Architeuthis can only eat relatively small prey?

What is known about the gut of Mesonychoteuthis? Is it much wider in diameter than that of Architeuthis?

Is there any real evidence as to the lifespan of these large squids? I read somewhere that cephalopods as a whole seem to have short lifespans, and that a very rapid growth rate is thereby implied for Architeuthis. What about Mesonychoteuthis?

There is a general rule that prey species are shorter-lived, and much more fecund, than their predators. It has been reported that the Patagonian Toothfish, which seems to be a very long-lived species, is a major part of the diet of Mesonychoteuthis. This might indicate that Meso. has a considerably longer basic life span than is typical for cephalopods.

Best wishes to all on this site.

Frank

That should of course read "Kat Bolstad". Sorry for the mistake.

(Ed. Not a problem; corrected the above post; Steve O)

From Kat Bolstad's article on "Deep Sea Cephalopods" on this site, I learn that the gut of Architeuthis dux has a maximum relaxed diameter of only 10mm. Is the implication here that Architeuthis can only eat relatively small prey?


well, im just about as far from an expert there is on this board but, the prey is going to be shredded fairly small by the time it gets past the radula... i cant remember, but you might want to check the "challenge" thread in phys and bio, that involved stomach contents of archi...

my attempt at quasi intellectual conversation :)

From Kat Bolstad's article on "Deep Sea Cephalopods" on this site, I learn that the gut of Architeuthis dux has a maximum relaxed diameter of only 10mm. Is the implication here that Architeuthis can only eat relatively small prey?

What is known about the gut of Mesonychoteuthis? Is it much wider in diameter than that of Architeuthis?

Is there any real evidence as to the lifespan of these large squids? I read somewhere that cephalopods as a whole seem to have short lifespans, and that a very rapid growth rate is thereby implied for Architeuthis. What about Mesonychoteuthis?

There is a general rule that prey species are shorter-lived, and much more fecund, than their predators. It has been reported that the Patagonian Toothfish, which seems to be a very long-lived species, is a major part of the diet of Mesonychoteuthis. This might indicate that Meso. has a considerably longer basic life span than is typical for cephalopods.


Hi Frank. That's a rather interesting post. The oesophagus of Architeuthis and Mesonychoteuthis is of comparable diameter, in that it is narrow in both (10-15mm). Both squid eat prey larger than this greatest dimension, but the prey is chopped up into quite small pieces by the beaks and (theoretically) further masticated by the radula (although the radula doesn't really seem to play a major role in chopping the prey up, in that squid flesh in the gut of Architeuthis isn't scoured by the radular teeth).

Sitting atop the computer right now is one of the two statoliths from the Mesonychoteuthis squid. It is tiny (~ 2mm greatest dimension); Mesonychoteuthis would appear to be a pelagic squid (benthopelagic and benthic forms, as a rule, have larger (relatively speaking) statoliths). By sectioning this tiny statolith (something we'll leave to George Jackson, Hobart) we'll be able to count tiny rings (much like those seen in section of a tree trunk). It is assumed that these rings are deposited on a daily basis, but this has not been validated for cold-water deep-sea species of squid. We're attempting validation now (it has been validated for shallow-water tropical species). So, at this point, we'd be uncomfortable estimating age.

Your third point, the relative life spans of predator and prey, is most interesting. The smaller Mesonychoteuthis are eaten by larger Patagonian Toothfish, so it could become a circular argument. But this is definitely worthy of further consideration; consider it filed in the back of the head - we'll look into this.
Kindest
Steve

Steve, many thanks for your informative reply to my queries. Like so many others, I look forward with interest to more reports from yourself and Kat, as you further study these fascinating creatures.

I gather that you are tending to believe that Architeuthis is a largely "passive" predator - and therefore of little "danger" - whereas Mesonychoteuthis is powerful, aggressive, and formidable.

Some shark analogies come to mind. Architeuthis is perhaps a sort of squid equivalent of the Megamouth, Basking, and Whale sharks, even more so of the mysterious Goblin Shark (Mitsukurina) which is also benthopelagic or benthic. On the other hand, Mesonychoteuthis is a Great White or a Tiger!

I must admit to a tinge of sadness that Architeuthis has lost its status as the scariest cephalopod. This reminds me of the recent discoveries of meat-eating dinosaurs larger and more formidable than Tyrannosaurus. Actually the scientific name 'Architeuthis dux' is entirely comparable to 'Tyrannosaurus rex'. Was one named in analogy to the other?



The smaller Mesonychoteuthis are eaten by larger Patagonian Toothfish, so it could become a circular argument.


The Patagonian Toothfish itself seems to be quite an imposing creature, for a bony fish.

Among other things, I look forward to further report on the eyes of Mesonychoteuthis. Cephalopod eyes are especially interesting of course, partly because of their remarkable similarity to vertebrate eyes - indeed in one respect, the arrangement of the retinal cells, they are, at least theoretically, slightly more efficient than vert. eyes. And because of their similarity to our own, ceph. eyes have an "emotional" impact on us, which the very different eyes of insects can never have - note how cartoon films such as "Antz" give the insects vert./ceph. type eyes.

Regards and best wishes

Frank

Thanks, WhiteKiboko, for your reply.

I too am very far from being an expert!

[I'd love to visit NC sometime and attend a college football or basketball game involving UNC, Duke, or NCState :) ]

Regards

Frank

The analogy, "Architeuthis is to a basking shark as Mesonychoteuthis is to a great white" is an interesting one.

Of course, great whites have been largely defined for the general population by the movie Jaws, for better or for worse... Well, ok, probably for worse. :) Also, the summer of 2001 saw a number of sensational shark attacks that received tons of press here in the US, and probably elsewhere.

Luckily, it would seem a Mesonychoteuthis attack on a beach-goer in 3 feet of water is about as likely as a gorilla attacking a spectator at a hockey game. Hey, how's that for an analogy? :D

Anyway, back to YOUR far better analogy... you were of course comparing their generally aggressive natures, not necessarily their propensity to attack humans. The thought of Architeuthis as a relatively mellow creature is fascinating.

I tried to search through some of Steve and Kat's earlier posts on Architeuthis aggressiveness, but didn't find anything that went into further depth (although I may have not been using the right search terms). Would be interested in any thoughts or speculation in this area?

Steve and Kat,

Congratulations, and I hope to read more about your discoveries... Your description of the anatomy was... odd... I'll admit, you have my attention.

Sorry that I've been away, but needed to take a self-imposed exile to Texas... Will have to return soon.

Sushi and Sake,

John

This should have aired on Discovery Channel News (Canada) a week-or-so ago; we've yet to receive copies so don't know what the final product looked like.

Cheers
Us

Steve talks like Phantom...Ghost Who Walks...the Marine Biologist Who Cannot Die...

So much for your secret identity!

I am but a figment of your imagination. My real name is Paul.

will paul come back as superman?

Has anyone seen this documentary, perchance? :?:

No, but I saw Steve the other day - almost as good as the real thing!

Paul will be in Wellington again in a couple of weeks to check out the flounder collections; will make it for a Friday bev. ; I'll be the one in the red lycra suit. Gotta check out those cranchiid collections to see whether there's any juvenile Mesonychoteuthis from NZ/proxim waters, and octopoteuthid collections to finish off two more MS's. Both are proving to be real cans of worms.

Can either Steve or Kat tell me? Is the inner mantle really black?? Or was it ink? or an artifact of filming? J

A frightening thing just occurred to me (have just woken up, so must have been thinking about this). The standard theory is that the inner wall of the mantle is dark, in the case of Mesonychoteuthis, black, to shield light from bioluminescent prey in the squid's stomach/stomach caecum from shining through the mantle, identifying the squid to potential predators.

Other than the sperm whale (I'm not sure whether the whale uses eyesight or sonar to locate prey), what possible predator could there be down there that would take on a full-grown colossal squid? :goofysca: :goofysca:

There must be another reason for the dark-pigmented inner-mantle wall of the colossal squid (it is this or there is something even more formidable down there ..... shudder!). Prey (as in Patagonian Toothfish), don't bioluminesce (as far as I know), so the dark inner-mantle wall probably doesn't serve to conceal the squid from potential prey .....

Something weird is going on. Anyone with any suggestions?

Having given this 2 coffee's worth of consideration I have come up with 2 suggestions:

1) Cranchiid squid like Teuthowenia can pull their head entirely within their mantle, inking within the mantle and appearing like grapes (this is actually what I thought we had in one sample several years ago - deep-sea 'grapes'). As the eyes of Mesonychoteuthis have photophores, perhaps this animal can also withdraw the head (and arms) within the mantle ... ouch ... and the black lining of the mantle wall conceals any bioluminescence from the eyes. You still have to have a large-enough predator to warrant this behaviour, however. Perhaps the smaller animals need to be able to do so, and the character state is just carried forth through to the adult (where it isn't really required, but is a non-lethal behavioural attribute ... as in it doesn't harm the animal to be able to do so, rather than it being advantageous to be able to do so).

2) The ink is bioluminescent .... and for the same reasons as above, this character state is retained by the adult, and is a non-lethal condition.

Any further suggestions?

Steve,

Don't know how effective head retraction would be in eliminating the light signature from the photophores, but I don't know what Mesonychoteuthis' orientation in the water column might be (I'm waiting on "the theory":wink:). Unless the seal between head and mantle was very tight, you'd still see a cylindrical shaft of light emanating from around the retracted head. If Mesonycho held its head down, that leakage would probably not draw diving predators, but...I'd also worry about damage to the eyes incurred during a fast, emergency retraction. Ouch is right.

I'd think that cupping the eye with a looped tentacle would be about as effective at masking the ocular light organs. Can Mesonycho stretch its arms and inter-arm web up high enough to hide the eyes, ala Vampyro?

If the "stealth lining" theory is correct, perhaps it was most useful back when there were 12-meter, apex-predator sharks to worry about.

:roll:

Clem

If the "stealth lining" theory is correct, perhaps it was most useful back when there were 12-meter, apex-predator sharks to worry about. Clem

Now this is a very interesting proposition!! Viewing things in time and space .... I forgot that extra dimension! Anyone familiar with 'prehistoric sharks' in the Antarctica of yester-millenia?
Cheers
O

With the exception of the mako shark, which does occur in tropical waters, all extant lamnid sharks (white shark & relatives), are primarily colder-water animals. Paleoecological studies suggest megalodon did not extend its range into cool temperate or polar waters. Unless the colossal squid ventures into warmer waters it's not the predator/prey relationship you're looking for :periscop: ….

.... Myopsida, I just gotta admit, that's pretty darn interesting information!

What are the chances that there are sedimentary deposits somewhere in modern-day Antarctica .... or perhaps a frozen Colossalodon ( :shock: ) frozen in the bergs?

Why has nobody pitched a doco like this? "Raising the Colossalodon" (beats mammoth any day)

Just passed this thread by Discovery Channel.

The response ...

Antarctic dig sounds interesting - except there is a couple of miles of ice
before soil isn't there? :lol:
.....
Never thought of that :oops:

there are many areas of Antarctica that are ice free and fossil rich...
Chatterjee et. al. (1984) reported on marine reptiles (plesiosaurs) from Seymour Island. Four millon year old whale fossils are being excavated near Davis Station by MacQuarie University; drilling through the ice in West Antarctica has revealed fossil diatoms from 65,000-400,000 bp; I picked up some shells on Ross Island myself. . . . do I feel a funding application coming on?

Elasmo-research.org has a (perhaps) relevant article about giant-toothed sharks, Antarctica and long-term shifts in oceanic temperatures. (http://www.elasmo-research.org/education/evolution/paleoecology.htm) I was intrigued by the suggestion that great whites started using cold waters for pupping as a response to C. megalodon's mastery of warmer, coastal seas.

:idea:

Clem

Fascinating stuff Clem.

May I ask everyone to let this thread develop as it has, and to not digress (as some threads can), as it is being monitored closely by documentary folk.

Fossil sharks, whales, toothed beasts, large squid, hooked squid, Antarctica, warm/cold water masses, life cycles of these beasts (Recent or fossil) and the likes .... and of course any relevant digression .....

Thanks
Steve

There must be another reason for the dark-pigmented inner-mantle wall of the colossal squid (it is this or there is something even more formidable down there ..... shudder!). Prey (as in Patagonian Toothfish), don't bioluminesce (as far as I know), so the dark inner-mantle wall probably doesn't serve to conceal the squid from potential prey .....

Something weird is going on. Anyone with any suggestions?


Formidable pointy-toothed predators lurking in the darkness are an exciting thought. :wink: But could there also be the possibility of something rather smaller, but which finds strength in number? Just a thought from a humble undergrad.

But could there also be the possibility of something rather smaller, but which finds strength in number? Just a thought from a humble undergrad.

Don't let the undergrad part concern you at all, FS; that's an excellent suggestion - one that I had not even considered!

Thanks
O

There must be another reason for the dark-pigmented inner-mantle wall of the colossal squid

Maybe its an adaptation to the 24-daylight during the austral summer - the dang things just like to pull thier heads in and sleep occasionally . . . .

There are sleeper sharks Somniosus sp. in Antarctic waters which reach lengths of 7 m (i.e. 6 m + imagination), but they are sluggish & unlikely to be a threat to a big squid (unless it was asleep as above)

Oh well . . its friday[/i]

Like most people who imagine lethal encounters between extinct/seldom-seen predators and prey, I'm probably guilty of imagining them as close-range slugfests between two animals of comparable mass and "armament.' That's how folks (including scientists) used to imagine contests between tyrannosaurids and ceratopsians, for example. It is equally true that the biggest, meanest predators sometimes behave in a "small" manner; a 4-meter great white may display great caution and stealth in stalking a sea lion.

I think Fluffysquid's point about the efficacy of teamwork, of groups of smaller animals co-ordinating a feeding assault on a larger one, is extremely apt.

Clem

Steve,

This kohl-lined mantle is making my head swim. If the female Mesonychoteuthis carries the developing eggs within the mantle cavity, would it confer any advantage upon the larvae if they developed within an environment of strictly controlled light levels? If Mesonychoteuthis has internal photophores, could mama use them in conjunction with a light-blocking mantle lining to prep the larvae's eyes for the lighting conditions they will experience upon independence, by alternating long periods of lightlessness with doses of bioluminescence?

Clem

Squid reproduction is quite a fascinating subject - something I tend to think about a little too much. At a mantle length of 2.5 metres this Mesonychoteuthis was nowhere near as large as the species can get (given the beak measurement, lower-rostral length of 37 mm, with max recorded for the species being 48 mm).

Of the ~ 90 species of squid that we get in New Zealand waters (quite high diversity, but our waters (our EEZ) extend from near tropical conditions in the north (off the Kermadec Islands) to near Antarctic conditions in the south, 55 degrees lat, off the Bounty, Auckland and Campbel Islands), so it should come as no surprise that we have so many species, and no surprise that more species turn up on a regular basis. (In the freezer back at work, picked up just last month, we have another large-bodied squid that represents another new record for our EEZ - probably ML of 0.5-0.75 metres.) If you want to work on weird and wonderful deep-sea squid systematics just come to NZ - there's enough work for everyone!

We've just submitted a paper to NZ Journal of Zoology (Kat, myself and a colleague from Massy University, Peter Ritchie) describing the egg massses of one commercially important species, for the first time. We haven't received the reviews back yet, but they shouldn't be that far away.

Now the egg masses for a handfull of these squid species are known from New Zealand waters (2 x Sepioteuthis spp., 3 x Sepioloidea spp. [2 of which are new species], Thysanoteuthis rhombus [yet to formally record from NZ waters], 1 species of Brachioteuthis and ~ 7 of enoploteuthid squid (Enoploteuthidae: Enoploteuthinae) - the enoploteuthid and brachioteuthid squids releasing eggs individually into the plankton - as in individual eggs spat out from the mantle/funnel and left to develop on their own, without being bound into any discrete/collective egg mass; the others all bind eggs into one of a mass that is either attached to the seafloor, or released as a free-floating gelatinous sphere or oblong structure. Some gonatid squid brood eggs within the arms; species of Todarodes (Ommastrephidae - like the Humboldt squid) also release eggs into the water column (in the form of a gelatinous sphere). BUT, and to cut a long story short, the egg masses of the numerous cranchiid squid (of which Mesonychoteuthis is an example) that we get in NZ waters (and that occur worldwide) are, to the best of my knowledge, completely unknown, or at least not reported in the literature. This is quite a shocking state of affairs/ignorance for 2003 don't you think! We need more people studying reproduction in squid, especially the exciting deep-sea fauna.

A partially intact male Mesonychoteuthis does exist - I believe recovered from the stomach contents of a sperm whale, alluded to in a paper by Nancy Voss (years ago .. I forget the details), and I believe accessioned into the collections of the USNM (Smithsonian Institution). I do not believe that this male has been described. To the best of my knowledge I am unaware of any fully mature female (given ours was only submature). Moreover, I am not aware of any mated female Mesonychoteuthis. NOW, if the USNM male specimen referred to earlier is just an arm crown (as is often the case), then we have no idea what sort of penis/terminal/reproductive organ it has. As no mated female is known/has been described, we don't know where the spermatophores are implanted on/in her. As a consequence we have no idea whether the female broods young at all, and as such, we don't know whether the darkened lining of her mantle wall would serve a function as you suggest Clem.

There is another paper by Rodhouse & Clarke (1985 I recall) that describes paralarval/larval Mesonychoteuthis specimens, and there was something in the description of the earliest stages of these paralarvae that lead me to believe that maybe the female released through her mantle or funnel individual eggs (with quite a bit of yolk); I don't know why - it is just a gut feeling that I have. It was this or that the eggs were bound in some gelatinous matrix, but hatched from this sphere/oblong structure at an early stage with much residual yolk.

So, I don't believe that Mesonychoteuthis broods embryos within the mantle, but really cannot justify why - it is just a 'feeling' that I have. The next 'major press release' someone will have will be the capture and reporting of either the mature male or fully mature female Mesonychoteuthis. When the male is reported we'll be in a better position to speculate on possible reproductive tactics (in mechanical terms); when the mature female is captured we will be able to determine whether fertilisation occurs within the mantle, possibly within the oviducts, or, alternatively, externally, either within the mantle or outside the mantle (maybe in the arms, with an egg mass being cradled as we propose for Architeuthis and is thought to occur in ommastrephid and some gonatid squid), with or without subsequent brooding (some gonatids are thought to carry the eggs around with them in their arms). In the interim we might learn an awful lot about studying the reproductive habits of smaller, more abundant cranchiid squid species, and from this extrapolate to possible reproductive/brooding behaviours of the larger colossal squid. We are looking into this now. If you are at all interested in deep-sea squid reproduction then come to New Zealand; I cannot promise you any answers but I can promise you some sensational material to work on, and some pretty interesting discussions - like this thread is proving to be.

All I can tell you is that when we opened up that colossal specimen that everything inside looked weird. I was not familiar with such anatomical organisation .... so believe something rather interesting might be happening.

I'd like to say thanks to everyone so far - you know we could have a similar discussion about almost any squid species.

Does that in any way address/answer your question?
Cheers
O

Does that in any way address/answer your question?

Steve,

Did I ask a question?

:notworth:

Clem

Re: Black lining to the mantle in Mesonychoteuthis.

Do you have any suspicions as to the posture Mesonychoteuthis adopts in the water (whilst not chasing Patagonian toothfish, that is)? It's just a thought but if Mesonychoteuthis tends to drift with its arms and tentacles angled downwards and with its head tucked into the mantle to hide the bioluminescence from the photophores around the eyes, (thanks, Clem), it would be very hard to spot from above by cetacean predators. I realise that Mesonychoteuthis is a powerful swimmer but is it not possible that it adopts this defensive posture during periods of rest?

Although Mesonychoteuthis may not use ammonia ions in a similar manner to Architeuthis and probably would not drift at a 45 degree angle as Architeuthis' physiology dictates, I don’t think that would necessarily belie the colossal squid from adopting a similar posture if it so chose to do so.

Although the sperm whale, I believe, hunts using a combination of its eyes and echo-sounding, the latter probably being increasingly useful the deeper the whale dives, as we know Mesonychoteuthis does come to the surface, could a defence such as this be of any use? I have read that sperm whales do not tend to feed on surface cephalopod species even though they often abound in the same feeding grounds, which strikes me as somewhat odd, so perhaps the presence of Mesonychoteuthis in surface waters is a survival strategy in itself.

As an aside, I wonder if there is any evidence of these large squid species forming the diet of killer whales?

I have read that sperm whales do not tend to feed on surface cephalopod species even though they often abound in the same feeding grounds, which strikes me as somewhat odd, so perhaps the presence of Mesonychoteuthis in surface waters is a survival strategy in itself.

Phil,

Now, that's an intriguing thought. A pod of diving whales would generate a mass of echo-locating "cones," widening and converging as the pulses move deeper and away from the whales' heads. The deeper a prey item lives, the better the chances it will be visible in the return. If Mesonychoteuthis were closer to the surface, its chances of escaping detection might be improved.

On the other hand, the ratio of Mesonychoteuthis beaks to Architeuthis beaks in whales' stomachs would suggest that the Colossal has some disadvantage that no amount of light-signature moderation or vertical movement can overcome. We're both waiting on "The Theory" of Mesonycho's attitude in the water, but I'd guess it was generally horizontal, with the tail and arms angled slightly downward from the fulcrum point of the head. If so, that may be its Achilles heel vis sperm whales.

A horizontal Mesonychoteuthis would reflect a much larger sonar image to a diving whale than a squid hanging at 45º would; presenting an end-on view with a smaller sonar cross-section (and significantly less dense tissue composition) might have given Architeuthis an edge, if it's comparatively lesser place in the sperm whale's diet is any indication. As you say, maybe Mesonychoteuthis reacts to being "painted" sonically by rotating to a vertical position and putting out the lights, keeping still and ready to fight.

As for killer whales, you've got me good and stumped.

:|

Clem

Clem and Phil:

Check out this link:

http://www.cetacea.org/orca.htm

Orcas are pretty much mammalian sharks with a brain. I wouldn't be surprised to see hem eat relatively large species of squid (Dosidicus, maybe the occasional hapless Moroteuthis, Taningia, etc.). Apparently there is evidence, just no one seems to have recorded just WHAT species were eaten.

If I find more, I'll let you know.

Sushi and Sake,

John

If I may humbly ask a question, do we have any conclusions as to the growth rate and age of the 2003 specimen following examination of the statolith?

I believe the statolith(s?) went to a colleague of ours who does some work on them, and I haven't heard anything further, but it would be good to follow that up...

Thanks Kat, I'll watch this space.

I have a vague three -four year thing grumbling at the back of my mind, so that's bound to be way out!

Cranchiid squid like Teuthowenia can pull their head entirely within their mantle, inking within the mantle and appearing like grapes (this is actually what I thought we had in one sample several years ago - deep-sea 'grapes'). As the eyes of Mesonychoteuthis have photophores, perhaps this animal can also withdraw the head (and arms) within the mantle ... ouch ... and the black lining of the mantle wall conceals any bioluminescence from the eyes. You still have to have a large-enough predator to warrant this behaviour, however. Perhaps the smaller animals need to be able to do so, and the character state is just carried forth through to the adult (where it isn't really required, but is a non-lethal behavioural attribute ... as in it doesn't harm the animal to be able to do so, rather than it being advantageous to be able to do so).
...elsewhere in the forums ob brought up the 1981 Meso specimen caught by a Russian trawl. We were discussing Mesonychoteuthis eyes. The '81 squid's eyes look very well-preserved...which is amazing, when you consider that the squid was trawled. The mantle and arms look as banged-up as you'd expect, but the visible portion of the head hasn't suffered nearly so much abuse. Trying to account for the high level of preservation of the most delicate parts, I recalled Steve's earlier post. The photo of the '81 Meso suggests to me that large sub-adults are capable of retracting the head into the mantle cavity, and that's what this squid did when the trawl hit it.

Thoughts?

Clem

Hmmmm... which might explain why the head looks so much smaller than the mantle, because it has to fit inside the mantle.

Hmmmm... which might explain why the head looks so much smaller than the mantle, because it has to fit inside the mantle.

I agree. And looking at this photo with the latest discovery in mind, the head does look quite smaller than the mantle. I never really noticed that before.
Interesting stuff!

rather interresting stuff here. something that kept occurring to me was that the reason for "cloaking capability" might well be courtship related,and that rather than some fearsome as of yet unknown predator the culprit was more likely members of it's own species. just a thought.

in the case of it being a courtship related issue,what i'm getting at is the possibility of rival males needing to escape one another when they are outmatched.

but something else occured to me while researching humboldts the other day...cannibalism. don't know if there's been any evidence in the stomachs of necropsied messies,but i'd run across an artice out there somewhere stating that in 1999 a tasmanian archi turned up with tentacle fragments in it's belly.

just shooting in the dark here.
thought i'd share and all that.

in the case of it being a courtship related issue,what i'm getting at is the possibility of rival males needing to escape one another when they are outmatched.
Hi Ubiquity,

That makes sense if the mantle of the cranchiid in question is transparent/translucent at the age of sexual maturity, and we do see that feature in smaller cranch squid. A grown Mesonychoteuthis's mantle is thick and opaque, and has a black-stained inner lining to boot, so inking inside itself may not have an appreciable benefit. It would be beneficial in the early stages of Meso's life, when it is more clear-bodied and vulnerable to a wider variety of would-be predators, including other squid. But, maybe I've been making an assumption about the self-inking being deliberate in the first place. Is it possible that it's involuntary, a consequence of the squid turning itself into a ball?

Cheers,
Clem

howdy clem! :smile:

involuntary?

you really think so?
...what's leading you to this conclusion?

and by the by it's good to be back. haven't had a chance to keep up with you guys in quite some time.

but something else occured to me while researching humboldts the other day...cannibalism. don't know if there's been any evidence in the stomachs of necropsied messies,but i'd run across an artice out there somewhere stating that in 1999 a tasmanian archi turned up with tentacle fragments in it's belly.

Hi Ubiquity. We put a paper out on this very thing in 2004 (NZ Journal of Zoology I recall). There's a version of it online here (http://www.tonmo.com/science/public/cannibalism.php), although I do note some corruption in some of the characters (if you want a pdf of the paper just pm me). The Zeidler & Gowlett-Holmes paper to which you refer (from Tasmania) didn't attribute the sucker rings in the stomach caecum of Architeuthis as belonging to Architeuthis, but they were certainly of a size consistent with them. There has been a further, more recent paper recording cannibalism in Architeuthis, based on genetic screening of stomach contents, so it doesn't appear to be too infrequent in occurence.

I'm afraid I can't chime in with regards to Russian trawl Meso's headsize, it's actually just slightly smaller than the mantle opening, but there's a notable "constriction" between the massive eyes and the posterior portion of the head.

Was this specimen's ML determined at all?

thanks for the link steve!
a good read for sure and very informative.

needless to say it has my wheels spinning.
so,..
any evidence of cannibalism in messies yet?

involuntary? you really think so?...what's leading you to this conclusion?
Hi Ubiquity,

Not a conclusion, but a question. There's another cranch squid, Cranchia scabra, that's been documented assuming the spherical configuration when threatened (a collected juvenile in an aquarium): Tolweb has the goods here. (http://tolweb.org/Cranchia_scabra/19542) Involuntary was the wrong word for me to use, secondary may be more like it, in that the primary defensive response might be ballooning, and the secondary response the release of ink...which, because the squid has become a tight ball, has no outlet. Again, this isn't a conclusion, but I wonder if the self-inking-while-ballooned behavior might represent the occasional pile-up of defensive responses that, while doing no harm, isn't directly beneficial.

Cheers,
Clem

perhaps there's a benefit we're overlooking?
i would be inclined to believe that there is
purpose in behavior even if we fail to see it.

given time we may find some very real reason
for it,who knows?

Hi Ubiquity. We put a paper out on this very thing in 2004 (NZ Journal of Zoology I recall). There's a version of it online here (http://www.tonmo.com/science/public/cannibalism.php), although I do note some corruption in some of the characters (if you want a pdf of the paper just pm me).
These character issues have been fixed! Inspecting other articles as well. Thanks for the heads-up!