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Colossal Squid Necropsy

Clem

Architeuthis
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Apr 6, 2003
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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
 

Steve O'Shea

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

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
 

frank h.

Hatchling
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May 16, 2003
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4
Mesonychoteuthis anatomy

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.

[I was a professional biologist many years ago, mainly in genetics and evolutionary biology, but I never worked on cephalopods. I am now a Chaplain (Christian) at South Bank University in London, England, and am doing some part-time lecturing and tutoring to students on various biological courses. My knowledge of cephs. is minimal, but I hope to learn a lot more from the various experts posting on this site]

A dormant interest in cephs. being reawakened by the recent reports in the media on 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
 

WhiteKiboko

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Re: Mesonychoteuthis anatomy

frank h. said:
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 :smile:
 

Steve O'Shea

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Re: Mesonychoteuthis anatomy

frank h. said:
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
 

frank h.

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Re: Mesonychoteuthis anatomy

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?

Steve O'Shea said:
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
 

frank h.

Hatchling
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Re: Mesonychoteuthis anatomy

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 :smile: ]

Regards

Frank
 

tonmo

Cthulhu
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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. :smile: 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? :biggrin2:

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?
 
Joined
Dec 24, 2002
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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
 

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