OK, I couldn't find a thread on this, either I'm blind, lazy, or correct:wink: so I thought I'd sart one to ask:

What is the actual composition of the cephalopod sucker rings? Are they just a form of chitin? I remember reading something about it in Engesser and Clarke (1988) Cephalopod Hooks,, Both Recent and Fossil but it didn't go into much more detail save that the belemnites he describes probably had a different chemical composition. I'm currently looking for papers on it, but I'm not sure if I'll find exactly what I'm looking for.

Graeme

As far as I'm aware tis Chitin. I have the proteins written down somewhere I'll look it out.

J

Hi

Maybe try this article:

Smith, A. M. (1996). Cephalopod sucker design and the physical limits to negative pressure. Journal of Experimental Biology, 199: 949-958.

K :sink:

This would make a marvelous thesis topic!!! I am afraid I cannot contribute further.

Just imagine, an analysis of ring & hook morphology & composition across a broad (comprehensive) range of taxa. Kind-of makes me get excited, deep down inside my sooty heart.

Hi

Maybe try this article:

Smith, A. M. (1996). Cephalopod sucker design and the physical limits to negative pressure. Journal of Experimental Biology, 199: 949-958.

K :sink:

Thanks, Tigerkatze. I already have that paper, it's a very good one. I think it just mentioned that the armature was just chitin.

This would make a marvelous thesis topic!!! I am afraid I cannot contribute further.

Just imagine, an analysis of ring & hook morphology & composition across a broad (comprehensive) range of taxa. Kind-of makes me get excited, deep down inside my sooty heart.
Yeah, that's kind of what my honours project is about: very interesting, but I can only scratch the surface with a 6 month time-allowance! I would love to go into it in more detail, like do a PHd over 3 years, now THAT would be a better timescale!!! :grin: If I had the time I would investigate the chemical composition of the chitin acroass a variety of species, but since it's coming close to the deadline, I just need it on paper really. The Tree Of Life said it was a mucopolysaccharide I think, but it attributed the chitin to the beaks and shell, but did not mention sucker rings. When it did it said they were of a horny substance:confused:

http://tolweb.org/notes/?note_id=587 it's in here.

Graeme

Hey Graeme,
Interesting hons project, so what is it exactly on? I mean which species are you looking at and what sort of data you have? or will you be having?

eups

erm.... well it's kinda a comparative morphology of suckers and armature in cephalopods really. Massive topic, so I can't really go into it in huge detail, but I guess it will act as a sort of starting point. If you want I could send you a copy once it's done. Deadline's something like the somethingth of March:lol: it's ever looming.

Graeme

Yeah, that's kind of what my honours project is about:

DUDE!!! That is so seriously fantastic!! The rings of Architeuthis are lined with carbonate deposits you know!! As for a PhD ..... well, if you are interested you know who to call (and I'm not talking 'Ghost Busters'). This is sensational stuff!!

Just tell me what you need in the way of equipment!

Hi Steve,
Gottcha! I can tell you some references to find out the rings composition.
Seeya,
muchiika

That would be great Whip Squid! If you could, that would make things a lot easier at the moment! I'd be very grateful for any help.

DUDE!!! That is so seriously fantastic!! The rings of Architeuthis are lined with carbonate deposits you know!! As for a PhD ..... well, if you are interested you know who to call (and I'm not talking 'Ghost Busters'). This is sensational stuff!!

Just tell me what you need in the way of equipment!

Yeah it's a really good topic, but really hard to find literature on. It would be better as a more practical project but considering I've only had half a year, that's not so easy either!:sad: I doubt I'll get published or anything, but I am hoping to put it up on a website at some point. I think I've had to sort of branch out as well, like incorporate the history, and possible evolutionary theories. Once I get it done, I can send it to you iffen you want, just as a word doc (most likely). I'm already drawing up a plan, and the finished draft has to be in for March 13th.

Actually, if anyone wants to proofread the dissertation before I hand it in then that'd be great, to get opinions from Ceph-experts. The only thing is that it will be far from comprehensive due to time and budget constraints; I'm hoping it will be a taster for the topic, and I aim to write it so that non-scientific types can enjoy it (if I'm allowed to!).
I'd LOVE to do a PHd on it Steve! I'd need to find some place that would take me though! :lol:

Graeme

I doubt I'll get published or anything, but I am hoping to put it up on a website at some point.

I'm sure plenty of folks around here would love to read it-- why not ask Tony to put it into the science articles archive?

Whoo, cool! It depends on if it's good enough though, of course!:wink:

Graeme

The Tree Of Life said it was a mucopolysaccharide I think, but it attributed the chitin to the beaks and shell, but did not mention sucker rings.

Chitin is a polysaccaride. Not sure if that's going to help, but just thought of it as a point of clarification. Good luck!

Cheers!

Yeah I know what the basic structure is, but I was under the impression you got lots of different variations.

Graeme

DUDE!!! That is so seriously fantastic!! The rings of Architeuthis are lined with carbonate deposits you know!! As for a PhD ..... well, if you are interested you know who to call (and I'm not talking 'Ghost Busters'). This is sensational stuff!!

Just tell me what you need in the way of equipment!

Dude, did you just say "dude"?

Duuude....

So from what embryonic tissues are suckers derived? I mean, along its evolutionary ontogeny, if the suckers have become a section for external calcareous (or chitinous) development, could this be an evolutionary throwback to the shell?

John

Chitin is a polysaccaride. Not sure if that's going to help, but just thought of it as a point of clarification. Good luck!

Cheers!

So are they chitinous, or calacareous, or both?

Chitin, I think. Only calcareous part in a ceph is the internal shell of cuttles, as far as I'm aware...

Graeme

Chitin, I think. Only calcareous part in a ceph is the internal shell of cuttles, as far as I'm aware...

Graeme

Er, I think you're forgetting nautilus in that blanket statement. I've read somewhere that the argonaut shell was evolved independently rather than being related to the shell that was lost in the coleoids, but I'm not sure how they know that or what it's made of. Given its shape, it seems likely that it inherits some from the archaic shell formations of the original ceph ancestry.

Particularly given the the Honolulu aquarium is one of the few places to be able to raise nautilus from eggs, it's be really nifty if Martindale et. al. did the same sort of HOX control analysis for nautilus that they did for the Euprymna, and we could see how the HOX controls the layout for the shell and the non-decapod arrangement...

(see http://www.nature.com/nature/journal/v424/n6952/abs/nature01872.html;jsessionid=4FD50828DF36 DE4CD9D3F63D7FFA444E and http://pharyngula.org/comments/558_0_1_0_C/ )

Aye... that too! Nautilus as well! I didn't foprget I was...err... testing you!

Graeme

ammonites???

Landman et. al., 2006, Jaws of late Cretaceous placenticeratid ammonites : how preservation affects the interpretation of morphology. American Museum novitates ; no. 3500 (http://digitallibrary.amnh.org/dspace/handle/2246/5679)


They are preserved as steinkerns with a thin film of black material, representing diagenetically altered chitin. X-ray diffraction analysis of samples of this material indicates that it consists of magnesium-rich c...

didnt read it all but the rest of the abstract (after the ...) reads: calcite, pyrite, and amorphous material (organic compounds).

was just looking into argonaut shell info on tolweb and saw this interesting factoid at http://tolweb.org/tree?group=Haliphron_atlanticus&contgroup=Argonautoida

Unlike other members of the argonautoid families, Haliphron has a remnant of the true shell - a short, thick almost gelatinous stylet (Voight, 1995). H. atlanticus, like other members of the argonautoid families except species of Argonauta, has a hydrostatic organ (Bizikov, 2004).

if it really is a vestigial shell, I'd expect it to be calacareous as well, but it doesn't say. That's the first I've heard of this-- does anyone know what its shape is like? That's the only internal shell I've ever heard of in an octopod... it seems like it'd say a lot about what the early coleoid octo-ancestors looked like...

TOL also says:
Argonauts are muscular, pelagic octopods. Females secrete a thin calcareous "shell" in which they reside

and

Presence of external shell in females secreted by the dorsal arms.

so I guess argonauts' shells are indeed calcium-based as well. The "secreted by the dorsal arms" seems like another good candidated for comparing the HOX control of argonaut shell excretion to nautilus!

ammonites???

Sorry, I should have said coleoids... which kinda goes for Nutiluses too.

Graeme

Ok, I have another question: How are the rings created? What secretes the chitin?

Actually I have another question: Are ceph's born with the full quota of suckers, only they're much smaller, or do they acquire more as the arm grows?

Graeme

Ok, I have another question: How are the rings created? What secretes the chitin?

Actually I have another question: Are ceph's born with the full quota of suckers, only they're much smaller, or do they acquire more as the arm grows?

Graeme

They definitely 'grow' them as the arms increase in length. How the rings are created .... well, that's another thesis .... and would involve a tremendous amount of histology (and comparative anatomy). What a tremendous subject for research that would be!

Steve, would Auckland uni ever consider offering a place for a PHd on sucker rings, be it composition, development or what I'm looking at: comparative morphology?
.... just out of curiosity...

Graeme- only scraping the surface, but at least its a start

My mind is ticking over as to how it would be done. I could not offer a stipend (as in living allowance scholarship), but could offer a full-fees scholarship (the cost of your enrolment would be zero $); you'd just have to accommodate & feed yourself.

One problem that I see with a programme like this is the histology, especially because you'll be sectioning through a hard structure that will want to destroy the soft part prep when the blade goes through. You'd want to replace the sucker ring with something that is softer - through some fan-dangled technique that I don't know about, but I am sure is common practice elsewhere (with bone).

You'd need ontogenetic series of identified species in pretty much all families of squid and octopus (otherwise you'd go insane if you had to identify them yourself).

You'd want to look at the composition of the sucker rings and hooks - and we've got all the toys here to do that (just don't ask me how to operate them or interpret the data; we have other people that can do that).

It would be very interesting!!

one other problem is that I know nothing about histology (or if I do, I'd have to try and locate it in the dark recesses of my brain! Not an entirely sanity-safe thing to do!:lol: ). You are getting me interested though! What I'll try to do just now is find out more about doing PHd's. I wanna try and get everything coursewise done first before I can relax and think about the future (time aint a luxury for me at the moment:cry:). Although like I said, I am interested in finding out a wee bit more!

I think it would be interesting too, if slightly sanity-draining.:wink: :razz:

Graeme

I can offer some IDs on ontogenetic series of onychoteuthids. :smile:

Graeme, have you seen this paper?

The Structure and Adhesive Mechanism of Octopus Suckers

William M. Kier and Andrew M. Smith

Integr. Comp. Biol., 42: 1146-1153 (2002)

Full text available here:

http://www.bio.unc.edu/faculty/kier/lab/pdf/Kier_Smith_2002.pdf

Yeah I have that one and the earlier one they both did, from 1990

the morphology and mechanics of octopus suckers. I've used them quite a bit, as well as Smith's earlier cephalopod sucker design and the physical limits to negative pressure.

Graeme