Squid Beaks and Surgical Implants

cuttlegirl;119592 said:
Hmm... The gladius has ridges in it, which might be growth lines. I need to do some more reading before replying on analogies to cuttlebones...

weeelllllll they're not as defined as an actual ridge (at least not in N. sloanii :roll:) See attached piccy in the word doc!

not sure how they originate however I know that the increments in bivalve shells are calcium (and/ or aragonite) in a protein matrix, so perhaps the calcium has been lost and the protein matrix remains.

J
 
How's this, then:

Squids have a pen made of chitin, like crab shells. Cuttlefish have, in the same place, a cuttlebone made of some calcium stuff like a seashell... but some octopuses and their relatives have something like the pen also made of chitin. This is weird, because squids and cuttles are supposed to be more closely related to each other than they are to octopuses, but it's pretty much believed that their last common ancestor had a calcified internal shell like the cuttlefish. Did the squids and octopuses lose their shells in the same way? What would this tell us about how they're related or what the last common ancestor was like, since squid- and octopus-like animals haven't left much of a fossil record?

I'm not trying to be too jargon-heavy, it's just sometimes easier to express things the way they're discussed in papers, and anyway, I need some practice with some of this stuff. On the other hand, if you can't explain something without jargon, it's usually a sign that you don't understand it, so writing the version in this post is probably character-building for me as well.
 
Keith;119634 said:
oh no that wasnt sarcasm. my bad

oops, my bad, too, I guess... but it did get me to wake up and think about how much I was using two dollar words where it wasn't really that important to my point. It's an interesting exercise to put the "use the vocabulary in a context where people can learn it" version next to the "how can this be explained so that it makes sense directly" version.

Like I said in another recent post, one of the things I like about TONMO is that there's a range from professional researchers to grade school students, so it's worthwhile trying to make sure we cover all the bases... of course, we'll probably always have both academic discussions and enthusiastic novice questions, and shouldn't have every discussion cover both, but this got me thinking about looking for opportunities to cover a wider range...
 
yea. thats the best part of tonmo. super collective ceph knowledge. its awesome. i probably wouldve had at least one dead octo by now if i hadn't been recommended to this site. to be honest, i was completely clueless. i had no idea about the 3 month cycling to make sure your tank is mature, the set up of a tank, their unusually high waste production, i didnt know a thing.
 
Jean;119596 said:
weeelllllll they're not as defined as an actual ridge (at least not in N. sloanii :roll:) See attached piccy in the word doc!

not sure how they originate however I know that the increments in bivalve shells are calcium (and/ or aragonite) in a protein matrix, so perhaps the calcium has been lost and the protein matrix remains.

J

Yeah, increments is a better term, in my sleep-deprived state I couldn't come up with a better word than "ridges"... That's why I didn't continue with my post about cuttlebones, I wanted to be sure I was correct before I posted something...
 
monty;119568 said:
so, obviously cuttlebones (presumably including spirula) and nautilus shells are calcium based... are squid pens and the vestigial shells of some octos also rather than chitin? How about statoliths? I know squid sucker rings are also chitinous. How about radulas? and yeah, I could probably look this stuff up if I wasn't lazy... Is it pretty much across-the-board that all cephs can make both calcium and chitin based hard bits?

There's a lot of Gastropods and Polyplacophorans who have metal in their radulas. That is SO beyond cool.
 
Fujisawas Sake;119671 said:
There's a lot of Gastropods and Polyplacophorans who have metal in their radulas. That is SO beyond cool.

VERY cool, so much fun to tell a group (kids OR adults) about it, listen to them all tell you you're a fibber then whip out a preserved radula and a magnet (metal is magnetite you see!) fun fun fun :twisted:

J
 
I would be in awe at that demonstration! Where does the metal COME from to be incorporoated? It can't be animal produced so it must be eaten/collected from something.
 
dwhatley;119705 said:
I would be in awe at that demonstration! Where does the metal COME from to be incorporoated? It can't be animal produced so it must be eaten/collected from something.

magnetite is a form of iron which is in seawater, so they must incorporate it from the seawater, but I don't really know the mechanism and I've not been able to find a satisfactory explanation anywhere!

J
 

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