Why is the Giant Squid so giant?

[Melbe]

Is the giant squid so big because of abyssal giantism(because it lives in the deep it becomes big; as seen in sea spiders- shallow water ones are small, deep-sea can be as large as 80cm), or does it live in the deep because it is so big?
Just curious!
Melissa

[Steve O'Shea]

For this I have no correct answer Melissa.

To digress, I believe Architeuthis to be quite closely related to the likes of Moroteuthis (another genus with 'large' species), Onychoteuthis and Ancistroteuthis on morphological, anatomical and genetic grounds. But there would be huge debate if I were to suggest it (so pretend I never wrote this, ok).

The paralarval forms of these genera, in different families (Architeuthidae and Onychoteuthidae) are almost inseparable through to mantle lengths of ~ 10mm. At mantle lengths smaller than this the two differ slightly in shape, and in chromatophore distribution.

The adult Architeuthis doesn't really differ from its paralarval form - it is like a giant paralarva, whereas at mantle lengths in excess of 12 mm Moroteuthis develops hooks on its tentacle clubs (the expanded distal-most part of the tentacle); in Onychoteuthis and Ancistroteuthis these develop earlier. Otherwise each has 4 rows of suckers on the tentacle club in the paralarval stage (and Architeuthis retains this character state through into the adult form). I think Architeuthis has a photophore (light organ) on the end of its ink sac, although it isn't supposed to have photophores (there's a very strange structure at the end of the ink sac in New Zealand specimens at least, that looks just like a photophore; should it prove to be one then this would render the Onychoteuthidae and Architeuthidae even more similar).

So, back to your original question, in a rather convoluted manner, speciation often happens in terms of size (instead of the acquisition of a new character or character state); as such you often find 'giant species' of this, that and the other - 'giant' being a relative term only. So the speciation leap from an ancestral Architeuthis to a modern-day Architeuthis need not have been through a slow increase in size over many many millenia, it might have been a very sudden speciation event (one day the species 'woke up' and was seriously big; its' next of kin could have been a comparatively small species).

The likes of Moroteuthis live to much greater depths than Architeuthis (to 1000m in New Zealand waters, whereas Architeuthis is generally found within the water column at depths of ~ 500m), so if the two are related or have relatively Recent ancestry (that's if I ever suggested that they were related .... and of course I would never do that because people would yell at me), then Architeuthis may have suddenly grown larger and concurrently moved shallower than its ancestor.

Of course there's another reason that Architeuthis might be big, and that's because it is quite a passive beast that drifts in the water 10-or-so metres above a large shoal of large fish (hoki), dipping its tentacles into the school of fish and then quietly withdrawing them, unnoticed, expending very little energy in the process.

The blue whale, another rather friendly beast, also grew large, eating a diet of comparatively minute animals, as did the whale shark (two more examples of gross gigantisism), so you don't really have to live deep to be big (and in fact the deeper you go there's probably a tendency for the animals to get smaller). Your pycnogonid (sea spider) example is a good one, because the largest of these brutes do live down deep.

Not sure if I've answered the question at all, but until Tony builds that time machine into the new Tonmo board we'll only ever be able to guess what really happened. There is of course an alternative to what I propose above, and that is that the ancestral Architeuthis was twice the size of the modern-day Architeuthis - the species could actually be shrinking in time (like my brain). Another alternative, a consequence of a shrinking brain, is that everything written above is nonsense.

Any debate is welcome. My belief is that Architeuthis is just a giant paralarva with serious hormonal problems, subject to premature maturity.
Cheers
O

[TaningiaDanae]

The adult Architeuthis doesn't really differ from its paralarval form - it is like a giant paralarva, whereas at mantle lengths in excess of 12 mm Moroteuthis develops hooks on its tentacle clubs (the expanded distal-most part of the tentacle); in Onychoteuthis and Ancistroteuthis these develop earlier. Otherwise each has 4 rows of suckers on the tentacle club in the paralarval stage (and Architeuthis retains this character state through into the adult form). I think Architeuthis has a photophore (light organ) on the end of its ink sac, although it isn't supposed to have photophores (there's a very strange structure at the end of the ink sac in New Zealand specimens at least, that looks just like a photophore; should it prove to be one then this would render the Onychoteuthidae and Architeuthidae even more similar).

Any debate is welcome. My belief is that Architeuthis is just a giant paralarva with serious hormonal problems, subject to premature maturity.
Cheers
O

Fascinating. So the implication of this is that A. dux would simply be a huge but physiologically "arrested" form of Moroteuthis, Mesonychoteuthis, and even Taningia (referring to A. dux's vestigial or prototypical photophore).

IMHO your "giant paralarva" theory is not farfetched at all. In fact it seems analogous to the development of the amphibian Axolotl, which if I am not mistaken is simply a "prematurely mature" Salamander, a giant paralarva with external gills.

Definitely would like to hear more about this!

Tani

[Steve O'Shea]

Here's a definition of neoteny (word of the day) for you Tani, which is probably what we are talking about in giant squid:

"A slowing of the rate of growth of the somatic (nonreproductive) parts of the body of an animal, so that larval characteristics may persist when it reaches sexual maturity. The axolotl is a neotenous salamander that rarely assumes the typical adult form under natural conditions, although metamorphosis can be triggered by injection of thyroid hormone. Neoteny is also known in certain tunicates (primitive marine chordates)."

And another:
"1. Retention of juvenile characteristics in the adults of a species, as among certain amphibians. 2. The attainment of sexual maturity by an organism still in its larval stage."

...and yet another:
"The persistence in the reproductively mature adult of characters usually associated with the immature organism."

But here's another word, paedomorphosis, and here's the only online definition I can find for it:
"Paedomorphosis - condition in which a larva becomes sexually mature without attaining the adult body form"

Now many years ago I remember someone explaining to me that there was a significant difference between neoteny and paedomorphosis. Perhaps some bright spark who reads this has something to contribute to the discussion - I look forward to it.
Cheers
O

[TaningiaDanae]

Many thanks! Just looked 'em up and found this in a search:

http://science.kennesaw.edu/~rmatson/neoteny.html

But I still don't get the difference between the two terms. Enlighten me?

:? :?:

[Steve O'Shea]

I'm no wiser myself Tani, though I do wonder why they would have two 'big' words that both describe the same thing. We need to find ourselves an evolutionary biologist to answer this one. :grad:

With regard to Taningia, I'm afraid it is only distantly related to Architeuthis (despite having photophores). You'll find 3 illustrations of Octopoteuthis hooks in figure 6 of the 'guide to frequently used.....'; Octopoteuthis and Taningia are classified in the family Octopoteuthidae - one of the characteristics of which is possessing these hooks on the arms (and in having 8 arms in the adult form). Architeuthis lacks these hooks entirely. Many onychoteuthid squid possess photophores.

Plans for the future are to have online descriptions and illustrations for all of these different kinds of squid (but we'll probably do the octopus first, as I'm far more familiar with them).
Cheers
O

[Phil]

With reference to Octopoteuthis, is it true that the arms can actually detach if the animal is threatened? I've read that the arms wriggle and flash as a decoy. this seems a somewhat extreme action to take! I suppose the tissues must have a weak point at the base as with Ameloctopus. If so, what exactly triggers the detaching, is it an external pull, from, say, a predator, or a reflex muscle spasm within the base of the arm pinching off the rest of the arm?

How long does it take for the arms to regenerate, or are they lost for good?

Loads of questions there. Hope you don't mind!

[Steve O'Shea]

Interesting question Phil!

The genus Octopoteuthis is in dire need of systematic revision; a few species are reasonably well described but the majority are not. Therefore attaching a name to any one species is difficult (there will always be some uncertainty there). Now, having said this, and the reason for saying it, I recognise three species of Octopoteuthis in New Zealand waters.

They are (provisional identifications, until comparative material can be secured): Octopoteuthis megaptera (many specimens, the majority mature ), Octopoteuthis sicula (one specimen, immature), and Octopoteuthis sp. "giant" (one specimen, mature; possibly one other, immature - need to do detailed examination to confirm).

Every specimen that I attribute to O. megaptera from NZ waters has lost its arm tips. This is extremely frustrating as I cannot determine whether they had, and what the shape was of any photophores on the arm tips (a rather important systematic character); all specimens have been caught in nets of one variety or another, and therefore you can expect their capture to have been a traumatic affair, which might explain the loss of the arm tips).

The single specimen of O. sicula and the ?2 of O. sp. "giant" have all of their arm tips intact. Very unusual this - both were caught in nets (they differ in other characters - so I am not simply attributing them to a different species because their arms are intact).

So, the loss (jettison) of the arm tips during traumatic periods would not appear to be a characteristic of all species of Octopoteuthis, although for at least O.megaptera it would appear the normal behavior. How they do it and whether the arms can regenerate afterwards (I would imagine they would) I do not know.
Cheers
O

[Phil]

Thankyou for the information, Steve. Interesting stuff.

Popular books on animal life, such as the one in front of me now, seem to catagorise creatures into distinct pigeon-holes and give the impression that the systematics are cut and dried. They rarely point out that the relationships between groups and individual species is constantly undergoing revision. It's easy to forget this and take what one reads as gospel!

For the record, the species that I have the reference to for the detaching arms that continue to flash is for Octopoteuthis nielseni, accredited to the Eastern Pacific. I wonder what sort of evolutionary advantage could be gained by the loss of the two feeding tentacles in the juvenile. After all, one might would think that the tentacles would aid in food collection and be an advantageous feature to retain. Not really knowing much about the feeding habits of Taningia I wouldn't really like to hazard a guess!

[Steve O'Shea]

Tentacles are interesting things. For some squid they most definitely are used in the act of prey capture, especially when the structures are inordinately long (as in Mastigoteuthis, Chiroteuthis and probably Architeuthis), but that is not saying that these structures are propelled out at great speed to catch and restrain prey some distance from the animal. For many kinds of squid I believe the structures dangle naturally.

In squid like Nototodarus (ommastrephid squids - or common arrow squids), oceanic beasts with shorter tentacles, they are not shot out all-that-often either; on many (probably the majority of) occasions the prey is actually caught and restrained in and by the arms. The tentacles are actually held out in front of the squid, held together and 'functioning' or 'serving to function' as a pointer or guide for the squid to track its prey. The squid scrunches its eyes forward, lining the prey up along the tentacles (and distal-most tentacle clubs), then launches forwards and both catches and restrains the moving prey with its arms (rather than having the tentacles held within the arm mass, tracking the food with its eyes, having no guide whatsoever, propelling the tentacles out to restrain it, then withdrawing the struggling prey to the arms for restraint).

Octopoteuthis obviously cannot line up any prey along the tentacles, as it lacks them, so it has to do something different in order to localise, catch and restrain prey. The photophores probably play an important role here, but whether they function to attract prey, disorient prey, confuse predators, all or none of the above I really don't know (probably a combination of them). Its comparatively short and muscular arms are endowed with two rows of seriously wicked hooks, and its fins are enormous (relative to its overall size) and very muscular; probably in combination these hooks, arms, and fins render this animal an adept killing machine.

....actually, having hooks on your arms (like those of Octopoteuthis) and long tentacles probably isn't too good a thing. The tentacles themselves would constantly get snared and hooked on the arms. This raises an interesting point O :idea: (excuse me whilst I think out loud) .... hmmmm .... so how do squids of the Family Enoploteuthidae get on, as they have both hooks on the arms and long tentacles? I'll go have a look and see if there's some protective sheath somewhere.

...off I go :silenced:

[Steve O'Shea]

What a buzz :grad: I just learnt something (not that there's any surprise there). Very similar to Octopoteuthis in overall appearance (though in different families) is a genus called Ancistrocheirus; they're not very common at all (as adults - I might have a half dozen specimens), and like Octopoteuthis they posess two rows of seriously evil hooks along their arms; they differ (in a number of respects) most notably in that the genus retains the tentacles in the adult (and the tentacles are large and well formed - although none that I have is complete - I do in the juveniles though).

Either side of each row of hooks is a very fleshy and extensive membrane. The membranes on either side fold together and enclose the hooks within a groove, thus, possibly, protecting the delicate tentacle from snaring itself. The membrane is called (surprise surprise) a 'protective membrane'. The same 'protective membranes' are very well-developed in enoploteuthid squids also.

They've obviously been called 'protective membranes' for a good reason, so someone must have demonstrated their value/function before (so we just re-invented the wheel .... don't you hate that), but their function had never really dawned on me before (that they are extremely well developed in genera/species that possess both hooks on the arms and have long/functional tentacles) - it was just a name given to a structure in accordance with some illustration I'd seen. Not to worry (nobody ever taught me this so there may be a few others out there that don't know either).
Cheers
O

[Phil]

Thanks again, Steve.

'Protective Membrane', there's imagination for you! On the other hand, it's good to hear a term that is easily understandable instead of some convoluted Latin derivation. Imagine if a German researcher had named it!

Just a thought, but if Architeuthis hangs in the water column with the two main tentacles hanging loose and spread wide as with Mastigoteuthis, then would it really need to have this arrangement whereby the two main tentacles could lock together using its toothed suckers? It seems to me to be a more efficient arrangement to spread the net wider if the creature is not an ambush predator, implying that this ability to lock the tentacles together could be seen as a redundant feature. Yet Architeuthis has poor musculature and is thought to be a poor swimmer. It’s all very confusing!

It was very interesting your observation that the tentacles in Nototodarus function almost like a sighting arrangement on a rifle, could one assume Architeuthis uses its tentacles in a similar fashion? It would explain why the tentacles could be locked together. I suppose a similarity in general form (i.e exceptional length) to the tentacles in Mastigoteuthis and Chiroteuthis does not necessarily imply a similarity in function. Also, Chiroteuthis has a light organ at the tips of its tentacles whereas Architeuthis does not, implying a different feeding action.

I’m speculating but if Architeuthis does indeed use its tentacles in a similar manner to Nototodarus then Architeuthis would not necessarily be at a disadvantage due to its poor musculature as prey at Architeuthis’ normal depths is, (please correct me!), much slower moving.

I’m not sure I’m making much sense as I’m thinking this through as I write!

Thanks,
Phil

[Steve O'Shea]

It was very interesting your observation that the tentacles in Nototodarus function almost like a sighting arrangement on a rifle, could one assume Architeuthis uses its tentacles in a similar fashion? It would explain why the tentacles could be locked together. I suppose a similarity in general form (i.e exceptional length) to the tentacles in Mastigoteuthis and Chiroteuthis does not necessarily imply a similarity in function. Also, Chiroteuthis has a light organ at the tips of its tentacles whereas Architeuthis does not, implying a different feeding action.
Phil

If ever fortunate enough to see an Architeuthis with all of its skin intact (a marvelous sight) you will notice that the animal is dark red on every body surface, except two: the inner face of the tentacles themselves (light pink), which have the 'knob/sucker' arrangement that lock into an opposing sucker/knob on the other tentacle; and the inner face of the tentacle clubs (which is porcelaineous white).

In addition to the inner face of the tentacles being flattened , it is coarse, beset with innumerable minute bumps. These would provide a non-slippery surface, assisting the suckers and knobs in locking the two tentacles together.

Indeed [i]Chiroteuthis has the photophore at the very tip of the tentacles, but Architeuthis has those enormous eyes and brilliant white inner face of the tentacle clubs. I have no doubt that the adult could see them in the distance (the inner face is in stark contrast to the outer side of the tentacle clubs, which is a very dark red (in fact, darker than the skin of the mantle and head)).

Clasped together the two anaconda-like tentacles of Architeuthis likely writhe their way through the dark in search of prey. The prey (fish) would be sought out and grasped between the two tong-like clubs, then either slowly withdrawn (struggling) to the arms, OR the squid would lunge forward and restrain it with the arms. Of course 'lunging forward' is not going to go unnoticed, but these schools of fish (hoki) are extremely dense and widespread (hence their being a major fishery target); probably a scattering of fish one minute would be compensated by an influx of others the next (I think the forward lunge to be far more likely than the retraction of elastic tentacles).

That's my theory anyway ... I guess we'll all just have to wait and see whether there's any truth in it. Exactly how Chiroteuthis feeds is another matter altogether; there may be some interesting submersible observations here that could help answer this question.
Cheers
O

[Anonymous]

Not to change the subject of the original post but does the dark red coloration of Architeuthis also extend to the suckers on the arms :?: For some reason I got it in my head that they were pinkish. I know it's nit-picking but I am painting a model of Architeuthis and would like to be as accurate as possible. Sounds like one can get the job done with dark red, white, pink and black (for the eye and beak). Wrong? Right? In any case I feel I'm getting closer after my original job of light grey overall :oops: Thanks for the insight!

[Nancy]

Not to change the subject, but where did you find a model of Architeuthis?
Or did you make it yourself? :squid:

Nancy

[Steve O'Shea]

Just a quicky, but the suckers on Architeuthis are brilliant white, and the flattened inner face of the arms is slightly lighter in colour than the outer convex face of the arms (so pink as opposed to red would be a good colour).

....and following on from Nancy's question, how big is this model you are making, and what are you making it out of? Very interesting.
Cheers
O

[Anonymous]

Thanks Steve! In answer to your and Nancy's question I am currently working on a shadowbox deplicting Architeuthis and are using pre-made squid figures that I have found here and there. The ones I have are as follows:

(1) An eighteen inch rubberlike figure made by Safarai Ltd. and available from http://www.linkandpinhobbies.com/dinotoys.html

(2) Small plastic figure made by MPC Plastics and out of production.

(3) Six inch lead figure made by RAFM Minatures and also out of production (perfect for Phil's Nemo vs Kraken game).

In spite of my lack of artistic talent I do plan on handcrafting larger versions out of hydrostone and papier-mache and do want to be as accurate as possible although nothing as large as the life size figure my wife and I made out of snow last winter complete with red dye and paper plates for eyes (not a lot to do out here in Nebraska in the winter :roll: ) As enraptured as I am with Archi, I am spellbound by Mesonychoteuthis hamiltoni . . . . . . maybe a future model? Sorry this got off the intended topic (which was fascinating by the way) but I wanted to answer the questions directly. Salutations from the self-proclaimed squid capital of Nebraska! 8)

[Tintenfisch]

OMG, Snow Squid!!! That takes the prize for coolest snow creation... I made a huge kiwi bird once, but I think Archisnowthis wins arms down. Too bad there's not much white stuff at the moment for such divertments, eh. ;)
And oh yes, Omaha is DEFINTELY the squid capital of Nebraska. 8)

[Steve O'Shea]

Just checked out the hooks on the arms on a fresh-fixed Taningia that came in today (in overall facies very similar to Ancistrocheirus, the animal that had the extremely well-developed protective membranes running either side of its hooks, and with substantial tentacles), and Taningia (which lacks the tentacles in the adult) lacks the protective membranes either side of its hooks.

Very very interesting! One could leap to the conclusion that those membranes prevent the tentacles from becoming snared by their very own arm hooks; any other suggestions?
O

[Fujisawas Sake]

Hi,

Just wanted to throw my two cents in about the definitions posted earlier. My herpetology intsructor said that paedomorphosis as it pertained to the axlotl meant that the juvenile form could take one of two paths: an adult form (without gills), or the juvenile-looking (with gills) form. In other words, there is a "choice" of sorts (probably depending on the environment, hormones, and a few other factors.)

He also went on to say that neoteny is based more on ontongeny recapitulating juvenile characteristics as a rule, i.e., that the neoteny is present in all individuals as part of its evolutionary lineage. For example, we humans all tend to look like neotenic hominid young (large heads, roundish bodies, etc.).

These might not be exact definitions, as I think he went on to mention that these defs. were "close enough for government work". :roll: I hope this helps.

Getting back to the original topic here, just how big is the theoretical limit on the size of an Archi? If there was some mega-archi back some time ago, like my favorite mega "Jurassic Shark" Carcharadon megalodon (sp?) then, by crickey!... this thing must have been a massive hunk of squiddage!

Sushi and Sake,

John

[Steve O'Shea]

Interesting distinction between neoteny and paedomorphosis, John - I was hoping this thread/question would be picked up at some point, as it was left dangling; thanks. I'd like to explore this a little further myself, but right now I don't have time on my side. If anyone else has anything to contribute then PLEASE jump in.

Re this prehistoric 'mega squid' - that was a hypothetical case I gave (that it could be shrinking in time, as opposed to increasing). There is a tendency for people to think of the ancestral Architeuthis as being smaller than the modern-day animal, attaining its present size by way of gradual or spontaneous increase in size (depends whether you believe in periods of stasis followed by rapid bursts of change/evolution [punctuated], or the gradual acquisition of characters/change of character states [eg., size] through time). Who knows ...... But the animal could equally be decreasing in size as our fossil record really is quite poor for these animals/squid in general/and for octopus almost non-existent.

The maximums for the modern-day Architeuthis, almost certainly of which a single species, Architeuthis dux, exists world wide, are:
Length (mantle; female) 2.5m
Length (mantle; male) 1.7m

Total length (female, relaxed, not stretched like a rubber band, incl tentacles): 13m
Total length (male, relaxed, not stretched like a rubber band, incl tentacles): 10m

Total weight (female): 275kg
Total weight (male): 150kg

These are slightly larger than the largest specimens I've ever seen (of 96 of them). Even though 60 foot, or ~ 20m, is frequently cited as the max, and the specimen on which this was based was actually a New Zealand specimen that washed ashore back in the 1880's (or thereabouts), the specimen was NOT measured with a ruler, tape measure or yard stick - it was PACED (and this is clearly stated in the original publication) - this is overlooked in any subsequent citation to it. Moreover, this specimen almost certainly had been regurgitated from a whale stomach (in those bad old days) and was partially digested (and thus its length exagerated further, as they go to mush). Its tentacles were probably stretched out the thickness of a rubber band to make it larger/longer still (this can be done) ..... and the chap who 'paced' it probably took 'baby steps' and then exagerated some. People need their monsters, but the fact is they do not grow this large.

No specimen remotely approaching this size has been recorded since, anywhere, and so many have been measured world-wide now. All specimens we get in New Zealand are fully mature, and thus unlikely to grow any larger (they're not babies); those caught overseas/stranded are similarly almost always fully mature, and agree with the maximum sizes we get in NZ specimens (if not being slightly smaller/shorter).

Trying to reduce the size of this animal is, however, just about impossible - people refuse to believe it is actually smaller than it is. No matter what I do the same old hogwash is perpetuated in nearly every report ... and if its not its total length that they blow out of proportion then it is the size of its eyes, beaks or suckers...... It would be so much easier to raise $$ to find this animal if I was prepared to perpetuate the nonsense ... maybe I should just continue like everyone else?

Cheers
O

[Fujisawas Sake]

Steve,

Ah, well... I will admit that I would like to think that there were some monsters out there. For some reason, people need their monsters. Where I live the local legend is Bigfoot. A distant cousin has the Loch Ness Monster. I can name a million cryptozoological legends, each more fantastic than the last. From seas serpents to the chupacabras, I think that people need their monsters. I think that somehow these stories play on some deep seated desire to be part of something much bigger than ourselves. Go see "The Lord of the Rings: The Two Towers"... Samwise has a monologue which I think defines this to a tee.

I don't blame you for getting a bit frustrated. My first love was astronomy, and while I believe in life on many, many other worlds, I can't get myself to believe in the standard UFO stuff. Oh, I would LOVE to see a flying saucer complete with aliens, and there very well may be some out there, but the reality of science so often gets buried in the pseudoscience of legend and folklore. It frustrates me because science can be rewarding and so much more interesting than people are willing to believe. But the folklore can make for some great reading, and fun, if you're willing to treat it as such.

Heck, a sixty-foot Archeteuthis would be a sight to say the least. Maybe they exist, maybe they don't. Let's not detract from the fact that the deep sea has incredible lifeforms the likes of which we probably have not even considered yet.

If this doesn't make you feel better, then we could always fake an ammonite sighting and sell it to the Discovery Channel! :P

Just spending time waiting for the eventual cephalopod takeover,

John

[Steve O'Shea]

Just spending time waiting for the eventual cephalopod takeover
...I don't think this was a good month to quit smoking. How long have we got?

That ammonite is out there ... not necessarily on this planet .... but it would sure be a buzz to go looking for it. I've often dreamed of doing the sub thing down 9000 metres off northeastern New Zealand (into the Kermadec Trench) .... it's never been explored you know .... only problem is the deeper you go the reduced likelihood of finding the ammonite (implosion) [unless that shell is fluid filled]. Spirula manages to do it ... astronomical depths .... and you can crumble its shell in your hands (it's not that strong) .... so just maybe there's hope for us yet. In fact, why don't we build a submersible in the shape of a Spirula shell??? Hmmmmm.

[Fujisawas Sake]

...I don't think this was a good month to quit smoking. How long have we got?

Steve,

According to Animal Planet's "The Future is Wild", we have about 200 million years before the the Squid Dominion. You can find out more at:

http://animal.discovery.com/convergence/futureiswild/futureiswild.html

I like specials like these... I have two books by Dougal Dixon; After Man: A Zoology of the Future" and The New Dinosaurs: An Alternative Evolution. Yeah, for the most part its sci-fi, but evolution never stops, and its fun to dream about what lies ahead. Oh, and Steve, your 120 foot squid is only 200 million years away, and the trees belong to the Squibbons...

You really think that there are still ammonites out there?

[Steve O'Shea]

I think the chance of finding a live ammonite today is greater than the chance of a 120-foot-long terrestrial squid in 200 million years, unless there are rather serious changes in the atmosphere and gravity, and if so I don't think we'll have squibbons. Some many-armed thing could occur on land, look like a squid, but likely through some quirk of evolutionary convergence only. ...imagine that slime trail :yuck:

Maybe ammonites weren't even squid .... maybe the shells are simple buoyancy chambers of an extinct mega-slug. You have to wonder about those asymmetrical ones don't you ... perhaps they were benthic, screwing themselves into the sediment .... maybe they still are out there in the abyss.

[Fujisawas Sake]

Steve,

Chances are that the climate in 200 million years will be a lot different. As far as gravity, well... I doubt it, unless Earth loses some serious mass.

As far as cephs making the transition to land... Well, evolution is a harsh mistress. The types of selective pressures needed over time to create a land-walking ceph... Hmm... Hate to say this, but that's a real brain scratcher. I can't completely discount the possibility, only because I can't shake the feeling that Molluscs share a common, if not INCREDIBLY distant, relationship with the Arthropods and Annelids. The move to land would be tumultuous at best, and how they would solve the problem of non-skeletal muscle based movement... What would result would be akin to calling a therapsid reptile a human... It wouldn't be a cephalopod anymore, only a very, very derived descendant.

Well, anyway... About your ammonite idea: What if they were gastropods, but of the Order Pteropoda? A massive group of sea butterflies may sound farfetched, but so does the idea of undersea "lakes" and chemosynthetic-based ecologies. What if they were related to the Scaphopoda? If they were, let's hijack a sub and start digging!! :D

Also, what if the ammonites were actually paraphyletic groups of molluscs? Maybe some may have been cephs, others gastros, or even some other, long extinct Order? The shells could have been homologous across the early mollscan line. Food for thought

What really bakes my noodle is, what if some of these shells were INTERNAL? :shock:

:lol: *sigh* Only time will tell. Thanks for the reply!

Sushi and Sake,

John

[Steve O'Shea]

The pteropod idea is not so far-fetched John - it is something I've considered myself. Moreover, I am absolutely convinced that a number of ammonite shells were completely internalised - we had this discussion on an earlier board (since gone ... and I regret now not having transferred the content over).

It would pay, if you want to continue with this theme (internal vs external and anything to do with ammonites) to start up a separate topic on this board. By doing this we can clearly separate the two topics (giant squid and ammonites), and maintain succinct threads. I'm sure Phil would be pleased to see this subject up and running again also.

There's much to be added on this subject. I actually have Neil Landman (AMNH) visiting early next year (oooooh....that's tomorrow), and one of the things I wish to discuss with him is this internal/external business, and more info on the aptychus as a jaw or gizzard plate. The 'radular' (adj) teeth described for some of these ammonites are also more similar to gizzard teeth ..... I'll try and get him to bring some specimens with him so I can do some photography and post here. For all the world these structures resemble those we see in some opisthobranchs today (eg., Philine spp.).... There is no way that the buccal musculature associated with operating these jaws/aptychi could be accommodated within the last chamber of the ammonite, if their basic body plan was anything akin to that of Nautilus (I realise the relationship is distant). My only concern re the scaphopod/slug/gastropod/pteropod relationship is this siphuncle.

I'm rambling, but you've sparked my interest in the subject again.
Cheers
O

[tonmo]

we had this discussion on an earlier board (since gone ... and I regret now not having transferred the content over).
I'll see what I can dig up.

[Fujisawas Sake]

:shock:

Whoops~! You're right! I'll start a new thread.... Or.. I'll start posting on another...

:P

[Armstrong]

Melissa the correct answer is species. There are over 200 species of Squid in the ocean and each of these species grow to different lengths, sizes, and have different characteristics. Archetuthus which i dont think i spelled right but who cares is one of the species that can grow up to about 55 to even 60 feet in length including the 2 long prey grabing tentacles. Thats why Giant Squid are so big its because of the species type and this kind of species of quid that grows very large just happen to grow the biggest in size out of all the Squid species there are.

[Steve O'Shea]

....and there you have it :wink:

Welcome aboard Armstrong; you were rather busy there yesterday weren't you ... tiz hard to keep up right now.

Are you studying cephalopods, or is this a hobby of yours?
Cheers
Steve

[Fujisawas Sake]

D'OH!! *slaps head*

Sorry folks... upon further review of my notes, I should re-state the neoteny thing...

Paedomorphosis and Neoteny are pretty much the same... Neoteny is the retention of juvenile characteristics during and beyond sexual maturity... its the SAME as paedomorphosis.

BUT... there are two types:

Obligatory: Where juvenile characteristics are always retained

Facultative: Where environmental factors affect the neotenic characteristics and metamorphosis...

Thanks for your patience folks!

Sushi and Sake,

John

[Steve O'Shea]

Tiz all good stuff John! No head-slapping reqd
O

[Steve O'Shea]

Another explanation for giant squid 'gigantism' is copied below, taken from the link:

http://www.cnn.com/2003/US/South/01/23/arkansas.fossil.ap/index.html

Wherein "The professor said the cephalopod found by the students is a pathological giant, which possibly suffered from parasitic castration. In other words, parasitic algae destroyed the reproductive organs of the creature and the creature continued to grow."

....but for acquired gigantism like this to be passed from one generation to the next, as in inheritance of acquired characteristics, one would need one's reproductive organs .... and the likelihood of these being available (or existing) following 'parasitic castration' is pretty remote (having trees in your tubes sounds painful). Guess our good giant nautiloid was a dead-end in evolutionary history. I do wonder why the report singles out parasitic algae though ... have these a habit of infesting cephalopod reproductive systems?

[heydiddlesquiddle]

G'day Folks,
Thoroughly fascinating subjects you guys have here. I have been lost for two days in this site now and still cant find the will to move on!!!
Anyways, I am a non educated guy when it comes to scientific research, but I have spent hundreds and hundreds of hours reading everything i can about what makes animals and physics tick.
I noticed here the refections of how a squid uses his tentacles.
I am a very keen fisherman and every winter here in south east Queensland, Australia the squid come in to breed. Most of my catches of squid have been with the use of prawn style jigs or scoop nets, both used at night. I am yet to catch a squid by the tentacles on its first attack of the jig. They move in for the kill immediately with its arms as thier first attack. If I miss setting the hooks on that attempt, the squid will use its tentacles to "taste" the jig to see if its edible. If it decides its not worth trying again you will in no way entice it into another take.
As for how it postures while actively hunting under the lights, i have noticed that the tentacles will in most cases be retracted short and held slightly wider than thier arms.
There are two main types of squid here that I have access to. The most prolific is an Arrow squid, and the second is what we call a tiger squid.

I do have a question tho.

Do squid and octopus have an olfactory system of sorts for detecting scents?

I should have stayed at school and followed my childhood dream and become a biologist i think. A little late now to start uni for a degree at 38.

Keep up the fascinating studies folks, Take care and keep smiling. :))

Tony.

[Architeuthoceras]

In the article by Manger, Meeks & Stephen I refered to in this thread (http://www.tonmo.com/phpBB/viewtopic.php?t=144&start=15) (Dr. Manger is the professor interviewed in the news article above). They refer to living Giant cephalopods as phyletic giants with a reference to Cope's Rule. They also refer to living pathologic giant gastropods that have been castrated by nematodes (I dont know where the algae fits in). Alot of Actinoceroid (Rayonnoceras) fossils have been found in Arkansas that are less than 1 meter long, I think the fossil in the article is only the second Giant Actinoceroid found.

Dwarf ammonites have also been found. I have a picture on my site.
http://ammonoid.topcities.com/turonian.htm
The Pteroscaphites is considered a progenetic dwarf offshoot of the larger Scaphites.

:nautilus:

[Steve O'Shea]

Do squid and octopus have an olfactory system of sorts for detecting scents?


Heydiddlesquiddle, aka Tony, howdo. I have a lot riding on this very question myself. I am aware that pheromones have been identified in Sepia (cuttlefish)......but just how many squid release pheromones I don't know (yet). This is something we are to look at this coming year.

Neither squid nor octopus have an obvious 'nose', but a system is in place, somewhere. More to follow soon.

That parasitic algal business being responsible for neutering the aforementioned beast is probably another example of the press getting things all wrong. Thanks Kevin.
O

[Jean]

Hiya Heydiddlesqiddle, I'm certain that arrows ( Nototodarus spp anyway!) have some sort of olfactory system, no real evidence to support this, but on the odd occasion we've held live ones, they've been held in a very large and dark tank (Steve you'll know the ones I mean, the big concrete ponds under the lab building at Portobello!) Anyhow when we've fed (or attempted to feed) them they will be nowhere in sight but shortly after the food (usually filleted fish, until such times as we can get the fish traps out to catch live food!) hits the water they appear out of the gloom. Now unless they have some sort of super xray vision, my feeling is that they smell the fish.

BTW it's never too late to enrol at varsity, my Mum has this year and she's 64 in May!!

J

[heydiddlesquiddle]

Thanks Steve,
I'm glad to be here learning more and more each few mins :)

Thanks also Jean,
I have noticed that squid can react to other senses incredibly quickly.
I fish for squid always on the new moon nights as they are the darkest and i fish on piers which have lights on them. I generally dont fish under the lights due to crowds so i move away 30 feet or more and jig the shadowed areas for better results.
During mid winter here when the squid are around, if the action is slow I will tie on a pair of bean sinkers about 2 inches long on separate loops so they rattle together with the retrieve, and cast them out as far as i can. The retrieve i make is as fast as i can wind while jigging the rod furiously. Within seconds of the sinkers leaving the water the squid will start to appear. I have counted 23 squid appearing after one cast once before but that was outstanding, usually its 6 or 8 squid that appear. This sort of brings me to thinking they use a sense of vibration as well as extremely good vision for thier major hunting techniques. I have tried fish scents in the water before and the squid only appear after the bait fish begin to school around. That's what was making me wonder.

As for going to uni and changing careers Jean, I would dearly love to do that but unfortunately atm money is my biggest hurdle. The costs for uni to obtain a degree then a masters is out of my price range until i pay this house off.

Thanks for the replies folks and i will be looking for results of more ceph data in the future.
Keep up the excellent work guys and girls :))

Tony.

[Fujisawas Sake]

Heya!

Well, time to throw my two "scents" in (groan!) :lol: . "Smell" is kind of a relative term here, mostly since taste and smell are chemoreception, and therefore are related. I tend to think of them as pretty much the same underwater, where traditonal definition of smell doesn't quite apply here. Chems in the medium (water) are detected by cephs by a system of chemoreceptors on the suckers. So they do "tastesmell" the water.

An interesting side note: Many molluscs have small patches of sensory epithelium located near the gill or mantle wall called osphradia. These are chemosensory, and perhaps serve in bivalves as a sediment detectors. However, the only ceph with osphradia is Nautilus. I would theorize that the suckers of cephs are so specialized that osphradia would be unecessary.

Oh well... Sorry if this is a confusing post. Its late, and I can't sleep, so I decided to post. I'm wierd that way...

"Aye, breach thy last to the sun Moby Squid!"

Sushi and Sake (and Hello Panda! crackers),

John

[Jean]

As for going to uni and changing careers Jean, I would dearly love to do that but unfortunately atm money is my biggest hurdle. The costs for uni to obtain a degree then a masters is out of my price range until i pay this house off.

Don't I know it!!! I could buy a pretty fancy house in an upmarket part of town with my student loan!!!!!!!!

I agree that squid seem to be exeptionally sensitive with other senses, but we were keeping them with no other tankmates and out of curiousity we put the food in with a minimum of splashing. So I still feel that scent, taste, chemorecpetion .....whatever! plays a part. But vibration (& sight!) are also hugely important. When we put live baitfish in the squid appeared much faster, boy can these guys move!!!! there was definitely a different response time. With the live fish the squid "noticed" them far faster than with the fillets!

J

[Fujisawas Sake]

Jean,

Actually I agree wholeheartedly with you about sight and vibration. The cephalopod eye is unequaled among invertebrates, and vibration makes perfect sense considering the medium in which the creatures live. I personally believe that the squid is the molluscan "fish", that is, the molluscan answer to the ecological niche need for a raptorial predator. If you think about it, the shapes are similar, and the types of prey are also pretty much the same. Yeah, its not as convergent evolution as the shark/dolphin/icthyosaur, but pretty darn close.

I guess I tend to see patterns in nature...

Now why am I so lousy at calculus?!??! :)

Sushi and Sake, and Gnarly Teriyaki,

John