POST YOUR COLOSSAL SQUID QUESTIONS HERE

Steve O'Shea

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We've set this thread up for you to post any questions that you may have about the Colossal Squid here.

Please remember that it will be rather difficult for us to respond as quickly as we would like to between the dates of 26 April and 03 May, but we will do our very best to attend to them as and when we can. The www.TONMO.com community is large, with many experienced folk online, so we are sure that you will receive the expert advice that you want.

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Discuss with us. (note: discussion spans many pages)

:squidaut:
 
Well, here's one: Why is the collossal squid (seems to be anyway) so radically different, morphologically, than the giant squid? The fins, mantle, and "head" all seem so to represent a creature that sits and waits, rather than jetting around. The claws could hint at this as well, for grabbing prey and making sure the squid doesnt have to wait for food to wander by again.

I am an amateur to this still, but I am curious.
 
I've always thought of Messie as a fairly active hunter! That mantle is quite heavily muscled and I would think it can move very quickly when it chooses to. I've always pictured it cruisin' until it saw potential (large) prey, then a flurry of activity which would see dinner secured by the claws and then chomped down.

J
 
Size

I think I read that one of the first things you will want to determine is the sex of the animal - do you think if this is a female then it is close to the maximum size and if it turns out to be a boy, how much bigger do you think the female could be? I just also wondered what techniques you might use to help determine the potential size for the species?
 
daviddickinson;115384 said:
I think I read that one of the first things you will want to determine is the sex of the animal - do you think if this is a female then it is close to the maximum size and if it turns out to be a boy, how much bigger do you think the female could be? I just also wondered what techniques you might use to help determine the potential size for the species?

I can give a half-baked answer that the sex difference in size will probably be approximated by comparing it to other squid species. This may be a bit tricky, because Mesonychoteuthis is a cranchiid squid, and so it's not that closely related to other large squids. I don't know what the typical size difference is in the cranchiids, but I'm sure that's being taken into account.

The most direct way to estimate the max size, though, will be from beak measurements. Steve's lab has a collection of a whole lot of beaks collected from toothed whale stomachs, and have carefully been measuring the size of the beaks for years. So if one imagines that the beak grows at the same rate as the squid, you can scale the squid to the size of the largest beak they've found. They already did that with the immature 2003 animal, but with this one, they'll start to improve the guesswork on that: it's possible the animal keeps growing after the beak stops growing, or vice-versa, for example. Or just that the squid grows proportionally faster than its beak, or the beak than the squid.

In any case, I'm sure precise measurement of the beak is a priority for Steve & crew to relate it to their wealth of data in this department.
 
Yes there will be a relationship of beak rostral (see pic) length to body (usually dorsal mantle) length and weight........however, to create the regression equations you usually need many examples of known size (I used 1100 for N. sloanii). By measuring those beaks and lengths etc you can use Excel or similar to plot beak length against body weight/length and thus calculate an equation. I doubt Steve & Co will be able to do that as they just don't have the available specimens and these relationships are quite species specific. Steve's beak collection won't work because they don't have the size of the original squid eaten by the whale.

J
 

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Octodude;115344 said:
Why is the colossal squid (seems to be anyway) so radically different, morphologically, than the giant squid?

As Jean said, it's actually the giant squid we believe to be more the sit-and-wait type (very small fins, relatively weak mantle musculature, body not strongly attached to mantle - all things that would be problematic for prolonged, fast swimming), while the colossal appears to be a very active swimmer (extremely large fins, very thick, muscular mantle, head fused to the mantle as in all cranchiids).

The giant and colossal squids are in different families (Architeuthidae and Cranchiidae respectively); each family is a group of genera that have certain morphological traits in common, so some of the differences are 'because' they're in different families (or, you could say they're in different families because of some of the differences), e.g. the means by which the head is attached to the mantle. Within the families there can also be a wide range of morphologies - different relative fin-size or arm-length for example. Have a look at some of the cranchiids at the link above - even the eyes vary a lot (and some are very strange.) The cranchiids are morphologically quite diverse, so Mesonychoteuthis has some big (ha ha) differences even from other genera in the same family. With Architeuthis, it's hard to say what variations there could be within the family, because at present (according to genetics at least), there is only one genus and species worldwide, Architeuthis dux.

Hope this helps.

:smile:
 
Jean;115430 said:
Yes there will be a relationship of beak rostral (see pic) length to body (usually dorsal mantle) length and weight........however, to create the regression equations you usually need many examples of known size (I used 1100 for N. sloanii). By measuring those beaks and lengths etc you can use Excel or similar to plot beak length against body weight/length and thus calculate an equation. I doubt Steve & Co will be able to do that as they just don't have the available specimens and these relationships are quite species specific. Steve's beak collection won't work because they don't have the size of the original squid eaten by the whale.

J

Sure, but you've gotta admit, two data points works a lot better than one data point: at least then you can judge whether drawing a line of slope beak/mantle from the 2003 animal matches up with beak/mantle for the new one, and if it does then have a bit of confidence about guessing the mantle size from the biggest beak...
 
An appeal for questions? Ahhh. This I can do.

1. If the eyes are reasonably intact, I'd be curious to know if Meso, like other cranchiid squid, has eyes that are open to seawater.

2. Does the musculature of the arms terminate at the head, or does it extend all the way to the posterior of the squid's head? To visualize what I'm talking about, flex your fingers up on one hand so that the tendons on the back of the palm stand out. Fingers are arms, palm is head, wrist is posterior of the brachial crown and tendons are (speculative!) muscles. (If you want to go all the way, hold a marble in the web between middle and ring fingers and call it an eye.) If the arm musculature does go all the way to the back of the head, as the tendons in your hand go back to the wrist, does each arm have its own tube of muscle through the head or is the musculature shared?

3. If the internal photophore is present, does it appear large enough to be of any utility, or does it appear rather vestigial?

Thanks. This is all very exciting. I'm on Tintenfisch. I mean tentacularhooks. I mean tenterhooks.

Clem
 
Clem;115440 said:
An appeal for questions? Ahhh. This I can do.

1. If the eyes are reasonably intact, I'd be curious to know if Meso, like other cranchiid squid, has eyes that are open to seawater.

2. Does the musculature of the arms terminate at the head, or does it extend all the way to the posterior of the squid's head? To visualize what I'm talking about, flex your fingers up on one hand so that the tendons on the back of the palm stand out. Fingers are arms, palm is head, wrist is posterior of the brachial crown and tendons are (speculative!) muscles. (If you want to go all the way, hold a marble in the web between middle and ring fingers and call it an eye.) If the arm musculature does go all the way to the back of the head, as the tendons in your hand go back to the wrist, does each arm have its own tube of muscle through the head or is the musculature shared?

3. If the internal photophore is present, does it appear large enough to be of any utility, or does it appear rather vestigial?

Thanks. This is all very exciting. I'm on Tintenfisch. I mean tentacularhooks. I mean tenterhooks.

Clem

1. If it's not, it will call into question the whole taxonomy of squids... which would be fine with me :biggrin2:

2. I've been trying to research this sort of thing for my own nefarious purposes, and can say that it is extremely unlikely. Cephs don't really have any tendons at all, and for the most part they don't even rely on connective tissue for leverage; all their muscle action is based on the "muscular hydrostat" principles worked out by Kier. Certainly, there are no cephs that have anything like sheaths that have muscles that slide relative to adjacent muscles... except for the separate organs inside the mantle cavity, they're mostly big masses of muscle with a few non-muscle bits embedded in the muscle, but there's no parts that slide relative to each other...

More than you could ever want to know (almost) can be found at http://www.bio.unc.edu/faculty/kier/lab/publications.html

but Kier has a frustrating habit of describing the arms' and tentacles' cross section, but not what the geometry and innervation of the muscles is like as they merge together at the brachial crown. Why I see this is a frustrating omission is left as an exercise for the reader ( for now. :madsci: ) Particularly since the CAT scan data Steve & crew posted a few years ago doesn't show muscle fiber direction :banghead: )

3. You mean the intraocular photophore many cranchiids have, right? Have you been reading here:
The photophores of the squid family Cranchiidae (Cephalopoda: Oegopsida) | Journal of Zoology | Cambridge Core
?
 
monty;115448 said:
2. I've been trying to research this sort of thing for my own nefarious purposes, and can say that it is extremely unlikely. Cephs don't really have any tendons at al

:alarm::alarm::alarm::alarm::alarm:

Monty! No! Gaahhh! That's not what I was saying! I was merely using the appearance of tendons on the back of a human hand to illustrate my (speculative!) musings on the arm musculature, and how those muscles might extend from the buccal plane all the way to the back of the brachial crown, not unlike the configuration of a bullpup rifle. I've attached a pic to show where this notion came from. I've outlined in green the arms IV pair. Now, perhaps it's an accident of debriding and abuse from longliners, but it certainly appears that both arms IV share a connection to a single distinct muscular structure that terminates at the posterior of the brachial crown. My purposes aren't nefarious, but if all the arms are so anchored, I wonder how their actions would impact the eyes, which appear to be nestled between the muscular bases of arms II and III, and what advantage, if any, would be conferred on an animal that could squeeze with its arms and its head.

Now I'll go read those things you linked to.

Clem
 

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