How many Mesonychoteuthis hamiltoni on display?

CapnNemo;86443 said:
Wow, astonishing resolution.

What are those hooks made of? Same material as the beak?

They ought to be, and somewhat similar to your own fingernails, I'd hazard a guess. Just nastier.
 
as long as we're asking hook questions, what do the hooks of modern cephs look like when they're removed from their surrounding muscle? Several pages seem to suggest that belemnite hooks were not derived from sucker rings, but modern ceph hooks are, so I'm wondering what implications this has for the evolution of hooks in cephs-- were the new coleoid hooks an independent development? Did hooks turn to suckers, and then revert in some cases? What's the deal? Does anyone (Steve? Kat?) have a picture of a mesonychoteuthis hook that's been removed from the animal? Tolweb has this generic hook diagram but I can't find any references on how hooks differ between species, and this looks rather different from belemnite hooks.

Also, how different are messie's hooks from other squids? I read somewhere that messie is the only cranchiid with hooks (as well as being a cranchiid that's not small and transparent, which is a bit weird anyway... are the juveniles more glass-squiddy?)
 
Mesonychoteuthis arm hooks look like this, when removed from the muscular sheath. Sorry about the big copyright stamp - this is a publication in prep. Hopefully you can still get a good idea of what it looks like. :smile:
 

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And here are a couple of tentacular hooks from two species of onychoteuthid, Moroteuthis robsoni and Notonykia nesisi sp. nov. (in publication). ToLWeb has some nice SEMs of some other onycho hooks, too - you just have to look under individual species.
 

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Thanks, Kat! The Notonykia nesisi looks a lot more like the belemnite hooks... but that may be just coincidence or convergence, I suppose.
 
Hi Kat, this may be a bit of a weird question, but what do they feel like?

E.g. Are they rock solid or do they have some 'give' in their consistency? Are they sharp?

Do you know how strong the muscle is that pulls them? I'm trying to understand if the hooks are used like a grip on a shoe to stop prey slipping out by passively allowing the prey to be caught on the hook, or whether they actively come out from the suckers and act to cut into the prey, shredding it before it reaches the beak?

:mesonych: :squidaut:
 
monty;86472 said:
Also, how different are messie's hooks from other squids?

The two rows of hooks on Messie's tentacle clubs are capable of rotation/swiveling. Presumably this action is under neuromuscular control. Can any confirm? I'm pretty sure that this is unique to Messie. (See Factsheet)
Great stuff!

Cheers!
 
Originally Posted by Tintenfisch
The hooks can all move independently. Whether they actually do is another question... having no recorded observations of them swiveling on a live animal, we don't even know if the animal actively rotates them (whether individually or at once), or whether they just turn all the way around 'so as' (Steve's gonna kill me for suggesting directional evolution) simply not to be pulled out when the prey thrashes. If they were stationary, I think there'd be a greater chance of losing them once the squid had grabbed a presumably struggling Patagonian Toothfish.
 
somewhere, there's a movie clip of Steve or Kat articulating a hook during the dissection (or really, the associated press tour, I expect)

It looked like it could swivel freely for at least 270 degrees with almost no resistance in the dead animal.
 
WhiteKiboko;86586 said:
... whether they just turn all the way around 'so as' (Steve's gonna kill me for suggesting directional evolution) simply not to be pulled out when the prey thrashes.....

... you didn't think you could sneak reference to 'directional evolution' in without me noticing, did you? You had better go hide; this time I'm not counting to 30 you know!

A normal squid sucker (without hook) is also capable of swivelling, is it not? The fact that a hook swivels is therefore not particularly remarkable. In fact, have we not found all hooks on arms and/or tentacles in other squid can swivel to some extent? (Admittedly they do swivel a lot in Mesonychoteuthis, and fit into recesses in the tentacle club that appear well suited to accommodating a hook/sucker quite capable of swivelling through 360°).

.... 15, 16, 17, 18 ..... 27, 28, 29 .... (look out)
 
Steve O'Shea;86612 said:
... you didn't think you could sneak reference to 'directional evolution' in without me noticing, did you?

Dang... after 2+ years, you finally caught me. :roll: WK, when did I post that the first time? Obviously young and foolish. :wink:
 
not sure... i could only find me referencing it... granted i didnt search too hard after i found the quote with the gist of it...
 
Tintenfisch;86742 said:
Dang... after 2+ years, you finally caught me. :roll: WK, when did I post that the first time? Obviously young and foolish. :wink:

Young lady, when I've found you, after you've returned from doing your next round of sensational SEM photos and wonderful science, I will have to .... hmmmmm .....

... take a look at your pictures and go 'ooooohhhhh ahhhhhhhh'.

Saved by the SEM yet again! (She does beat me so!)
 
I've discovered a new artists interpretation from a Japanese website that I thought might be worth posting. It's from the same site as I took the images for the Reconstructions of Ammonoids and Nautiloids thread from.

Click here.
 

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