Could a Nautilus Shell, Squid Gladius, or similar structure eventually form the basis of a Spinal...












7














Ok, so, some quick background... I'm not an evolutionary biologist or anything, but I'm helping a friend with some alien design ideas, and at least one of them she designed and wanted help to somehow explain was a group that basically falls into the classic Star Trek "Humans but Kinda Weird-Looking" milieu... and while I was initially willing to handwave their existence with "Boy, space sure is wacky, what are the odds that it keeps making humans!", I kept thinking about it more and more, and I actually really liked the idea of something we might consider a "functional vertebrate" with seemingly mammalian- even HUMANOID- characteristics actually being a case of something we would possibly classify as an Invertebrate undergoing some Seriously Bizarre Convergent Evolution that took a completely different path from ours... Yet ended up with a Weirdly Similar Result?



So we ended up coming up with a pretty solid model for how this race evolved, why they have the adaptations that they do, and we have them pretty solidly fleshed out... Except that there's one thing that I'm not 100% sure about, and it's kind of a Big Freaking Deal if we want an alternatively-evolved "Vertebrate": given that the ancestor we envisioned for them was something akin to what might have happened if Cephalopods or other Molluscan Critters had somehow developed into Primitive Chordates, the way something like the Lancet did, How Would They Evolve A Skeletal Structure, and How different would it be from Ours?



So I looked back at something like an Ammonite, and wondered if it was possible for something that still had a vestigial mollusk-style shell after somehow developing an early Notocord to sort of... Use that as a springboard for developing Vertebrae to protect it, and the rest of the skeleton following suit? Could the "chambers" in the shell maybe... start to diverge into separate nested "bands to allow for freedom of movement, or something like that?










share|improve this question







New contributor




BonnetBee is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
















  • 1




    You are looking at organisms which are way too evolved, too specialized. For an idea of where vertebrates come form, look at the amphioxus. Fun factoid: among the inverterbrates, our closest relatives are the echinoderms (starfish, sea urchins, sea cucumbers, crinoids and their allies). Tunicates (salps, sea squirts) are some weird chordates.
    – AlexP
    Jan 4 at 22:09












  • Yeah, that's what I was worried about too... Though I guess since it's an alien world the Proto-Thing would just have to be LIKE something instead of being "The Thing But ____" XD
    – BonnetBee
    Jan 4 at 22:12










  • Though I guess the question I'm trying to ask is less "Can this Happen" and more like "Ok, assume These Things have Already Happened, and that somehow we now Have An Organism that has both a Cuttlebone/Gladius-Style Thing and a Notocord-ish Thing, what are some ways in which the One might start to develop into shielding for the Other?" Sorry for the confusion, I guess I didn't state that very clearly :( The Amphioxus thing is pretty helpful though, THEIR spines had to come from Somewhere, right? Maybe they'll give me some ideas, thanks! :D
    – BonnetBee
    Jan 4 at 22:22










  • The vertebral column does not sheath the notochord, it replaces it. The notochord does not need sheathing, it is a structural construction element. You are thinking of the neural tube, which is a separate structure.
    – AlexP
    Jan 4 at 22:36










  • Ohhhhh, that's actually really helpful! I only just started looking into how Spines actually work/where they come from and I might be in a little over my head here XD So the thing I'm looking to protect is the Neural Tube, not the Notocord... Ok, that might make researching a little easier, thanks! :D
    – BonnetBee
    Jan 4 at 22:42
















7














Ok, so, some quick background... I'm not an evolutionary biologist or anything, but I'm helping a friend with some alien design ideas, and at least one of them she designed and wanted help to somehow explain was a group that basically falls into the classic Star Trek "Humans but Kinda Weird-Looking" milieu... and while I was initially willing to handwave their existence with "Boy, space sure is wacky, what are the odds that it keeps making humans!", I kept thinking about it more and more, and I actually really liked the idea of something we might consider a "functional vertebrate" with seemingly mammalian- even HUMANOID- characteristics actually being a case of something we would possibly classify as an Invertebrate undergoing some Seriously Bizarre Convergent Evolution that took a completely different path from ours... Yet ended up with a Weirdly Similar Result?



So we ended up coming up with a pretty solid model for how this race evolved, why they have the adaptations that they do, and we have them pretty solidly fleshed out... Except that there's one thing that I'm not 100% sure about, and it's kind of a Big Freaking Deal if we want an alternatively-evolved "Vertebrate": given that the ancestor we envisioned for them was something akin to what might have happened if Cephalopods or other Molluscan Critters had somehow developed into Primitive Chordates, the way something like the Lancet did, How Would They Evolve A Skeletal Structure, and How different would it be from Ours?



So I looked back at something like an Ammonite, and wondered if it was possible for something that still had a vestigial mollusk-style shell after somehow developing an early Notocord to sort of... Use that as a springboard for developing Vertebrae to protect it, and the rest of the skeleton following suit? Could the "chambers" in the shell maybe... start to diverge into separate nested "bands to allow for freedom of movement, or something like that?










share|improve this question







New contributor




BonnetBee is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
















  • 1




    You are looking at organisms which are way too evolved, too specialized. For an idea of where vertebrates come form, look at the amphioxus. Fun factoid: among the inverterbrates, our closest relatives are the echinoderms (starfish, sea urchins, sea cucumbers, crinoids and their allies). Tunicates (salps, sea squirts) are some weird chordates.
    – AlexP
    Jan 4 at 22:09












  • Yeah, that's what I was worried about too... Though I guess since it's an alien world the Proto-Thing would just have to be LIKE something instead of being "The Thing But ____" XD
    – BonnetBee
    Jan 4 at 22:12










  • Though I guess the question I'm trying to ask is less "Can this Happen" and more like "Ok, assume These Things have Already Happened, and that somehow we now Have An Organism that has both a Cuttlebone/Gladius-Style Thing and a Notocord-ish Thing, what are some ways in which the One might start to develop into shielding for the Other?" Sorry for the confusion, I guess I didn't state that very clearly :( The Amphioxus thing is pretty helpful though, THEIR spines had to come from Somewhere, right? Maybe they'll give me some ideas, thanks! :D
    – BonnetBee
    Jan 4 at 22:22










  • The vertebral column does not sheath the notochord, it replaces it. The notochord does not need sheathing, it is a structural construction element. You are thinking of the neural tube, which is a separate structure.
    – AlexP
    Jan 4 at 22:36










  • Ohhhhh, that's actually really helpful! I only just started looking into how Spines actually work/where they come from and I might be in a little over my head here XD So the thing I'm looking to protect is the Neural Tube, not the Notocord... Ok, that might make researching a little easier, thanks! :D
    – BonnetBee
    Jan 4 at 22:42














7












7








7


2





Ok, so, some quick background... I'm not an evolutionary biologist or anything, but I'm helping a friend with some alien design ideas, and at least one of them she designed and wanted help to somehow explain was a group that basically falls into the classic Star Trek "Humans but Kinda Weird-Looking" milieu... and while I was initially willing to handwave their existence with "Boy, space sure is wacky, what are the odds that it keeps making humans!", I kept thinking about it more and more, and I actually really liked the idea of something we might consider a "functional vertebrate" with seemingly mammalian- even HUMANOID- characteristics actually being a case of something we would possibly classify as an Invertebrate undergoing some Seriously Bizarre Convergent Evolution that took a completely different path from ours... Yet ended up with a Weirdly Similar Result?



So we ended up coming up with a pretty solid model for how this race evolved, why they have the adaptations that they do, and we have them pretty solidly fleshed out... Except that there's one thing that I'm not 100% sure about, and it's kind of a Big Freaking Deal if we want an alternatively-evolved "Vertebrate": given that the ancestor we envisioned for them was something akin to what might have happened if Cephalopods or other Molluscan Critters had somehow developed into Primitive Chordates, the way something like the Lancet did, How Would They Evolve A Skeletal Structure, and How different would it be from Ours?



So I looked back at something like an Ammonite, and wondered if it was possible for something that still had a vestigial mollusk-style shell after somehow developing an early Notocord to sort of... Use that as a springboard for developing Vertebrae to protect it, and the rest of the skeleton following suit? Could the "chambers" in the shell maybe... start to diverge into separate nested "bands to allow for freedom of movement, or something like that?










share|improve this question







New contributor




BonnetBee is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.











Ok, so, some quick background... I'm not an evolutionary biologist or anything, but I'm helping a friend with some alien design ideas, and at least one of them she designed and wanted help to somehow explain was a group that basically falls into the classic Star Trek "Humans but Kinda Weird-Looking" milieu... and while I was initially willing to handwave their existence with "Boy, space sure is wacky, what are the odds that it keeps making humans!", I kept thinking about it more and more, and I actually really liked the idea of something we might consider a "functional vertebrate" with seemingly mammalian- even HUMANOID- characteristics actually being a case of something we would possibly classify as an Invertebrate undergoing some Seriously Bizarre Convergent Evolution that took a completely different path from ours... Yet ended up with a Weirdly Similar Result?



So we ended up coming up with a pretty solid model for how this race evolved, why they have the adaptations that they do, and we have them pretty solidly fleshed out... Except that there's one thing that I'm not 100% sure about, and it's kind of a Big Freaking Deal if we want an alternatively-evolved "Vertebrate": given that the ancestor we envisioned for them was something akin to what might have happened if Cephalopods or other Molluscan Critters had somehow developed into Primitive Chordates, the way something like the Lancet did, How Would They Evolve A Skeletal Structure, and How different would it be from Ours?



So I looked back at something like an Ammonite, and wondered if it was possible for something that still had a vestigial mollusk-style shell after somehow developing an early Notocord to sort of... Use that as a springboard for developing Vertebrae to protect it, and the rest of the skeleton following suit? Could the "chambers" in the shell maybe... start to diverge into separate nested "bands to allow for freedom of movement, or something like that?







reality-check creature-design evolution aliens






share|improve this question







New contributor




BonnetBee is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.











share|improve this question







New contributor




BonnetBee is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.









share|improve this question




share|improve this question






New contributor




BonnetBee is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.









asked Jan 4 at 21:19









BonnetBeeBonnetBee

1247




1247




New contributor




BonnetBee is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.





New contributor





BonnetBee is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.






BonnetBee is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.








  • 1




    You are looking at organisms which are way too evolved, too specialized. For an idea of where vertebrates come form, look at the amphioxus. Fun factoid: among the inverterbrates, our closest relatives are the echinoderms (starfish, sea urchins, sea cucumbers, crinoids and their allies). Tunicates (salps, sea squirts) are some weird chordates.
    – AlexP
    Jan 4 at 22:09












  • Yeah, that's what I was worried about too... Though I guess since it's an alien world the Proto-Thing would just have to be LIKE something instead of being "The Thing But ____" XD
    – BonnetBee
    Jan 4 at 22:12










  • Though I guess the question I'm trying to ask is less "Can this Happen" and more like "Ok, assume These Things have Already Happened, and that somehow we now Have An Organism that has both a Cuttlebone/Gladius-Style Thing and a Notocord-ish Thing, what are some ways in which the One might start to develop into shielding for the Other?" Sorry for the confusion, I guess I didn't state that very clearly :( The Amphioxus thing is pretty helpful though, THEIR spines had to come from Somewhere, right? Maybe they'll give me some ideas, thanks! :D
    – BonnetBee
    Jan 4 at 22:22










  • The vertebral column does not sheath the notochord, it replaces it. The notochord does not need sheathing, it is a structural construction element. You are thinking of the neural tube, which is a separate structure.
    – AlexP
    Jan 4 at 22:36










  • Ohhhhh, that's actually really helpful! I only just started looking into how Spines actually work/where they come from and I might be in a little over my head here XD So the thing I'm looking to protect is the Neural Tube, not the Notocord... Ok, that might make researching a little easier, thanks! :D
    – BonnetBee
    Jan 4 at 22:42














  • 1




    You are looking at organisms which are way too evolved, too specialized. For an idea of where vertebrates come form, look at the amphioxus. Fun factoid: among the inverterbrates, our closest relatives are the echinoderms (starfish, sea urchins, sea cucumbers, crinoids and their allies). Tunicates (salps, sea squirts) are some weird chordates.
    – AlexP
    Jan 4 at 22:09












  • Yeah, that's what I was worried about too... Though I guess since it's an alien world the Proto-Thing would just have to be LIKE something instead of being "The Thing But ____" XD
    – BonnetBee
    Jan 4 at 22:12










  • Though I guess the question I'm trying to ask is less "Can this Happen" and more like "Ok, assume These Things have Already Happened, and that somehow we now Have An Organism that has both a Cuttlebone/Gladius-Style Thing and a Notocord-ish Thing, what are some ways in which the One might start to develop into shielding for the Other?" Sorry for the confusion, I guess I didn't state that very clearly :( The Amphioxus thing is pretty helpful though, THEIR spines had to come from Somewhere, right? Maybe they'll give me some ideas, thanks! :D
    – BonnetBee
    Jan 4 at 22:22










  • The vertebral column does not sheath the notochord, it replaces it. The notochord does not need sheathing, it is a structural construction element. You are thinking of the neural tube, which is a separate structure.
    – AlexP
    Jan 4 at 22:36










  • Ohhhhh, that's actually really helpful! I only just started looking into how Spines actually work/where they come from and I might be in a little over my head here XD So the thing I'm looking to protect is the Neural Tube, not the Notocord... Ok, that might make researching a little easier, thanks! :D
    – BonnetBee
    Jan 4 at 22:42








1




1




You are looking at organisms which are way too evolved, too specialized. For an idea of where vertebrates come form, look at the amphioxus. Fun factoid: among the inverterbrates, our closest relatives are the echinoderms (starfish, sea urchins, sea cucumbers, crinoids and their allies). Tunicates (salps, sea squirts) are some weird chordates.
– AlexP
Jan 4 at 22:09






You are looking at organisms which are way too evolved, too specialized. For an idea of where vertebrates come form, look at the amphioxus. Fun factoid: among the inverterbrates, our closest relatives are the echinoderms (starfish, sea urchins, sea cucumbers, crinoids and their allies). Tunicates (salps, sea squirts) are some weird chordates.
– AlexP
Jan 4 at 22:09














Yeah, that's what I was worried about too... Though I guess since it's an alien world the Proto-Thing would just have to be LIKE something instead of being "The Thing But ____" XD
– BonnetBee
Jan 4 at 22:12




Yeah, that's what I was worried about too... Though I guess since it's an alien world the Proto-Thing would just have to be LIKE something instead of being "The Thing But ____" XD
– BonnetBee
Jan 4 at 22:12












Though I guess the question I'm trying to ask is less "Can this Happen" and more like "Ok, assume These Things have Already Happened, and that somehow we now Have An Organism that has both a Cuttlebone/Gladius-Style Thing and a Notocord-ish Thing, what are some ways in which the One might start to develop into shielding for the Other?" Sorry for the confusion, I guess I didn't state that very clearly :( The Amphioxus thing is pretty helpful though, THEIR spines had to come from Somewhere, right? Maybe they'll give me some ideas, thanks! :D
– BonnetBee
Jan 4 at 22:22




Though I guess the question I'm trying to ask is less "Can this Happen" and more like "Ok, assume These Things have Already Happened, and that somehow we now Have An Organism that has both a Cuttlebone/Gladius-Style Thing and a Notocord-ish Thing, what are some ways in which the One might start to develop into shielding for the Other?" Sorry for the confusion, I guess I didn't state that very clearly :( The Amphioxus thing is pretty helpful though, THEIR spines had to come from Somewhere, right? Maybe they'll give me some ideas, thanks! :D
– BonnetBee
Jan 4 at 22:22












The vertebral column does not sheath the notochord, it replaces it. The notochord does not need sheathing, it is a structural construction element. You are thinking of the neural tube, which is a separate structure.
– AlexP
Jan 4 at 22:36




The vertebral column does not sheath the notochord, it replaces it. The notochord does not need sheathing, it is a structural construction element. You are thinking of the neural tube, which is a separate structure.
– AlexP
Jan 4 at 22:36












Ohhhhh, that's actually really helpful! I only just started looking into how Spines actually work/where they come from and I might be in a little over my head here XD So the thing I'm looking to protect is the Neural Tube, not the Notocord... Ok, that might make researching a little easier, thanks! :D
– BonnetBee
Jan 4 at 22:42




Ohhhhh, that's actually really helpful! I only just started looking into how Spines actually work/where they come from and I might be in a little over my head here XD So the thing I'm looking to protect is the Neural Tube, not the Notocord... Ok, that might make researching a little easier, thanks! :D
– BonnetBee
Jan 4 at 22:42










2 Answers
2






active

oldest

votes


















4














Basal chordates lack a jointed vertebral column, and have instead a rigid cartilaginous "notochord".



A gladius is very similar to a notochord. If chordates could
do it, so can cephalopods.



However, I doubt that squids would become terrestrial. They're pelagic specialists. Most people use octopuses or cuttlefish for their terrestrial cephalopod ancestors.






share|improve this answer

















  • 2




    Yeah, we were actually thinking Cuttlefish, since her people often Radically Alter Their Skintone as a form of communication and expression :D
    – BonnetBee
    Jan 4 at 22:24










  • The entire point of the notochord is that it is not rigid. It is flexible and elastic. Its role is to store energy in the same way as the elastic limbs of a bow.
    – AlexP
    Jan 4 at 22:26












  • @AlexP Fair enough. I'll change it to "unbroken".
    – SealBoi
    Jan 4 at 22:33










  • Cool! So they could probably develop a Spine-Like thing? I'm assuming it might look a little different than ours, and would probably be made of something like Chitin and/or something like Aragonite, like a Cuttlebone... I'll look and see if anyone's asked about how that would affect them, maybe make a new question if no one has. :3
    – BonnetBee
    Jan 4 at 22:49










  • @BonnetBee I think gladii are made of calcium carbonate. This paper explains why vertebrates use calcium phosphate in their skeletons rather than other, more common materials: ncbi.nlm.nih.gov/m/pubmed/28563613 It's not exactly in layman's terms, but you could probably figure out the consequences of a non-calcium phosphate skeleton from the abstract.
    – SealBoi
    Jan 4 at 23:08



















1














how about this. Similar to how "whales had to wait until their noses migrated to the top of their heads" (quoting the book 'Sapiens' by Harari) in order to facilitate breathing while swimming, in your case it was the exoskeleton that migrated to the interior of the body, in order to more closely focus their protection on the nervous system. I can envision the soft tissues gradually "seeping through" to the outside of the exoskeleton in response to a shrinking exoskeleton, perhaps due to a shortage of calcium in the environment.






share|improve this answer





















  • Hmmmm! That certainly helps add to the theme of "Looks like a familiar thing but evolved RADICALLY differently", I like it!
    – BonnetBee
    Jan 4 at 23:37











Your Answer





StackExchange.ifUsing("editor", function () {
return StackExchange.using("mathjaxEditing", function () {
StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
});
});
}, "mathjax-editing");

StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "579"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});

function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: false,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: null,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
noCode: true, onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});


}
});






BonnetBee is a new contributor. Be nice, and check out our Code of Conduct.










draft saved

draft discarded


















StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fworldbuilding.stackexchange.com%2fquestions%2f135611%2fcould-a-nautilus-shell-squid-gladius-or-similar-structure-eventually-form-the%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown

























2 Answers
2






active

oldest

votes








2 Answers
2






active

oldest

votes









active

oldest

votes






active

oldest

votes









4














Basal chordates lack a jointed vertebral column, and have instead a rigid cartilaginous "notochord".



A gladius is very similar to a notochord. If chordates could
do it, so can cephalopods.



However, I doubt that squids would become terrestrial. They're pelagic specialists. Most people use octopuses or cuttlefish for their terrestrial cephalopod ancestors.






share|improve this answer

















  • 2




    Yeah, we were actually thinking Cuttlefish, since her people often Radically Alter Their Skintone as a form of communication and expression :D
    – BonnetBee
    Jan 4 at 22:24










  • The entire point of the notochord is that it is not rigid. It is flexible and elastic. Its role is to store energy in the same way as the elastic limbs of a bow.
    – AlexP
    Jan 4 at 22:26












  • @AlexP Fair enough. I'll change it to "unbroken".
    – SealBoi
    Jan 4 at 22:33










  • Cool! So they could probably develop a Spine-Like thing? I'm assuming it might look a little different than ours, and would probably be made of something like Chitin and/or something like Aragonite, like a Cuttlebone... I'll look and see if anyone's asked about how that would affect them, maybe make a new question if no one has. :3
    – BonnetBee
    Jan 4 at 22:49










  • @BonnetBee I think gladii are made of calcium carbonate. This paper explains why vertebrates use calcium phosphate in their skeletons rather than other, more common materials: ncbi.nlm.nih.gov/m/pubmed/28563613 It's not exactly in layman's terms, but you could probably figure out the consequences of a non-calcium phosphate skeleton from the abstract.
    – SealBoi
    Jan 4 at 23:08
















4














Basal chordates lack a jointed vertebral column, and have instead a rigid cartilaginous "notochord".



A gladius is very similar to a notochord. If chordates could
do it, so can cephalopods.



However, I doubt that squids would become terrestrial. They're pelagic specialists. Most people use octopuses or cuttlefish for their terrestrial cephalopod ancestors.






share|improve this answer

















  • 2




    Yeah, we were actually thinking Cuttlefish, since her people often Radically Alter Their Skintone as a form of communication and expression :D
    – BonnetBee
    Jan 4 at 22:24










  • The entire point of the notochord is that it is not rigid. It is flexible and elastic. Its role is to store energy in the same way as the elastic limbs of a bow.
    – AlexP
    Jan 4 at 22:26












  • @AlexP Fair enough. I'll change it to "unbroken".
    – SealBoi
    Jan 4 at 22:33










  • Cool! So they could probably develop a Spine-Like thing? I'm assuming it might look a little different than ours, and would probably be made of something like Chitin and/or something like Aragonite, like a Cuttlebone... I'll look and see if anyone's asked about how that would affect them, maybe make a new question if no one has. :3
    – BonnetBee
    Jan 4 at 22:49










  • @BonnetBee I think gladii are made of calcium carbonate. This paper explains why vertebrates use calcium phosphate in their skeletons rather than other, more common materials: ncbi.nlm.nih.gov/m/pubmed/28563613 It's not exactly in layman's terms, but you could probably figure out the consequences of a non-calcium phosphate skeleton from the abstract.
    – SealBoi
    Jan 4 at 23:08














4












4








4






Basal chordates lack a jointed vertebral column, and have instead a rigid cartilaginous "notochord".



A gladius is very similar to a notochord. If chordates could
do it, so can cephalopods.



However, I doubt that squids would become terrestrial. They're pelagic specialists. Most people use octopuses or cuttlefish for their terrestrial cephalopod ancestors.






share|improve this answer












Basal chordates lack a jointed vertebral column, and have instead a rigid cartilaginous "notochord".



A gladius is very similar to a notochord. If chordates could
do it, so can cephalopods.



However, I doubt that squids would become terrestrial. They're pelagic specialists. Most people use octopuses or cuttlefish for their terrestrial cephalopod ancestors.







share|improve this answer












share|improve this answer



share|improve this answer










answered Jan 4 at 22:16









SealBoiSealBoi

5,67412158




5,67412158








  • 2




    Yeah, we were actually thinking Cuttlefish, since her people often Radically Alter Their Skintone as a form of communication and expression :D
    – BonnetBee
    Jan 4 at 22:24










  • The entire point of the notochord is that it is not rigid. It is flexible and elastic. Its role is to store energy in the same way as the elastic limbs of a bow.
    – AlexP
    Jan 4 at 22:26












  • @AlexP Fair enough. I'll change it to "unbroken".
    – SealBoi
    Jan 4 at 22:33










  • Cool! So they could probably develop a Spine-Like thing? I'm assuming it might look a little different than ours, and would probably be made of something like Chitin and/or something like Aragonite, like a Cuttlebone... I'll look and see if anyone's asked about how that would affect them, maybe make a new question if no one has. :3
    – BonnetBee
    Jan 4 at 22:49










  • @BonnetBee I think gladii are made of calcium carbonate. This paper explains why vertebrates use calcium phosphate in their skeletons rather than other, more common materials: ncbi.nlm.nih.gov/m/pubmed/28563613 It's not exactly in layman's terms, but you could probably figure out the consequences of a non-calcium phosphate skeleton from the abstract.
    – SealBoi
    Jan 4 at 23:08














  • 2




    Yeah, we were actually thinking Cuttlefish, since her people often Radically Alter Their Skintone as a form of communication and expression :D
    – BonnetBee
    Jan 4 at 22:24










  • The entire point of the notochord is that it is not rigid. It is flexible and elastic. Its role is to store energy in the same way as the elastic limbs of a bow.
    – AlexP
    Jan 4 at 22:26












  • @AlexP Fair enough. I'll change it to "unbroken".
    – SealBoi
    Jan 4 at 22:33










  • Cool! So they could probably develop a Spine-Like thing? I'm assuming it might look a little different than ours, and would probably be made of something like Chitin and/or something like Aragonite, like a Cuttlebone... I'll look and see if anyone's asked about how that would affect them, maybe make a new question if no one has. :3
    – BonnetBee
    Jan 4 at 22:49










  • @BonnetBee I think gladii are made of calcium carbonate. This paper explains why vertebrates use calcium phosphate in their skeletons rather than other, more common materials: ncbi.nlm.nih.gov/m/pubmed/28563613 It's not exactly in layman's terms, but you could probably figure out the consequences of a non-calcium phosphate skeleton from the abstract.
    – SealBoi
    Jan 4 at 23:08








2




2




Yeah, we were actually thinking Cuttlefish, since her people often Radically Alter Their Skintone as a form of communication and expression :D
– BonnetBee
Jan 4 at 22:24




Yeah, we were actually thinking Cuttlefish, since her people often Radically Alter Their Skintone as a form of communication and expression :D
– BonnetBee
Jan 4 at 22:24












The entire point of the notochord is that it is not rigid. It is flexible and elastic. Its role is to store energy in the same way as the elastic limbs of a bow.
– AlexP
Jan 4 at 22:26






The entire point of the notochord is that it is not rigid. It is flexible and elastic. Its role is to store energy in the same way as the elastic limbs of a bow.
– AlexP
Jan 4 at 22:26














@AlexP Fair enough. I'll change it to "unbroken".
– SealBoi
Jan 4 at 22:33




@AlexP Fair enough. I'll change it to "unbroken".
– SealBoi
Jan 4 at 22:33












Cool! So they could probably develop a Spine-Like thing? I'm assuming it might look a little different than ours, and would probably be made of something like Chitin and/or something like Aragonite, like a Cuttlebone... I'll look and see if anyone's asked about how that would affect them, maybe make a new question if no one has. :3
– BonnetBee
Jan 4 at 22:49




Cool! So they could probably develop a Spine-Like thing? I'm assuming it might look a little different than ours, and would probably be made of something like Chitin and/or something like Aragonite, like a Cuttlebone... I'll look and see if anyone's asked about how that would affect them, maybe make a new question if no one has. :3
– BonnetBee
Jan 4 at 22:49












@BonnetBee I think gladii are made of calcium carbonate. This paper explains why vertebrates use calcium phosphate in their skeletons rather than other, more common materials: ncbi.nlm.nih.gov/m/pubmed/28563613 It's not exactly in layman's terms, but you could probably figure out the consequences of a non-calcium phosphate skeleton from the abstract.
– SealBoi
Jan 4 at 23:08




@BonnetBee I think gladii are made of calcium carbonate. This paper explains why vertebrates use calcium phosphate in their skeletons rather than other, more common materials: ncbi.nlm.nih.gov/m/pubmed/28563613 It's not exactly in layman's terms, but you could probably figure out the consequences of a non-calcium phosphate skeleton from the abstract.
– SealBoi
Jan 4 at 23:08











1














how about this. Similar to how "whales had to wait until their noses migrated to the top of their heads" (quoting the book 'Sapiens' by Harari) in order to facilitate breathing while swimming, in your case it was the exoskeleton that migrated to the interior of the body, in order to more closely focus their protection on the nervous system. I can envision the soft tissues gradually "seeping through" to the outside of the exoskeleton in response to a shrinking exoskeleton, perhaps due to a shortage of calcium in the environment.






share|improve this answer





















  • Hmmmm! That certainly helps add to the theme of "Looks like a familiar thing but evolved RADICALLY differently", I like it!
    – BonnetBee
    Jan 4 at 23:37
















1














how about this. Similar to how "whales had to wait until their noses migrated to the top of their heads" (quoting the book 'Sapiens' by Harari) in order to facilitate breathing while swimming, in your case it was the exoskeleton that migrated to the interior of the body, in order to more closely focus their protection on the nervous system. I can envision the soft tissues gradually "seeping through" to the outside of the exoskeleton in response to a shrinking exoskeleton, perhaps due to a shortage of calcium in the environment.






share|improve this answer





















  • Hmmmm! That certainly helps add to the theme of "Looks like a familiar thing but evolved RADICALLY differently", I like it!
    – BonnetBee
    Jan 4 at 23:37














1












1








1






how about this. Similar to how "whales had to wait until their noses migrated to the top of their heads" (quoting the book 'Sapiens' by Harari) in order to facilitate breathing while swimming, in your case it was the exoskeleton that migrated to the interior of the body, in order to more closely focus their protection on the nervous system. I can envision the soft tissues gradually "seeping through" to the outside of the exoskeleton in response to a shrinking exoskeleton, perhaps due to a shortage of calcium in the environment.






share|improve this answer












how about this. Similar to how "whales had to wait until their noses migrated to the top of their heads" (quoting the book 'Sapiens' by Harari) in order to facilitate breathing while swimming, in your case it was the exoskeleton that migrated to the interior of the body, in order to more closely focus their protection on the nervous system. I can envision the soft tissues gradually "seeping through" to the outside of the exoskeleton in response to a shrinking exoskeleton, perhaps due to a shortage of calcium in the environment.







share|improve this answer












share|improve this answer



share|improve this answer










answered Jan 4 at 23:29









kenken

1899




1899












  • Hmmmm! That certainly helps add to the theme of "Looks like a familiar thing but evolved RADICALLY differently", I like it!
    – BonnetBee
    Jan 4 at 23:37


















  • Hmmmm! That certainly helps add to the theme of "Looks like a familiar thing but evolved RADICALLY differently", I like it!
    – BonnetBee
    Jan 4 at 23:37
















Hmmmm! That certainly helps add to the theme of "Looks like a familiar thing but evolved RADICALLY differently", I like it!
– BonnetBee
Jan 4 at 23:37




Hmmmm! That certainly helps add to the theme of "Looks like a familiar thing but evolved RADICALLY differently", I like it!
– BonnetBee
Jan 4 at 23:37










BonnetBee is a new contributor. Be nice, and check out our Code of Conduct.










draft saved

draft discarded


















BonnetBee is a new contributor. Be nice, and check out our Code of Conduct.













BonnetBee is a new contributor. Be nice, and check out our Code of Conduct.












BonnetBee is a new contributor. Be nice, and check out our Code of Conduct.
















Thanks for contributing an answer to Worldbuilding Stack Exchange!


  • Please be sure to answer the question. Provide details and share your research!

But avoid



  • Asking for help, clarification, or responding to other answers.

  • Making statements based on opinion; back them up with references or personal experience.


Use MathJax to format equations. MathJax reference.


To learn more, see our tips on writing great answers.





Some of your past answers have not been well-received, and you're in danger of being blocked from answering.


Please pay close attention to the following guidance:


  • Please be sure to answer the question. Provide details and share your research!

But avoid



  • Asking for help, clarification, or responding to other answers.

  • Making statements based on opinion; back them up with references or personal experience.


To learn more, see our tips on writing great answers.




draft saved


draft discarded














StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fworldbuilding.stackexchange.com%2fquestions%2f135611%2fcould-a-nautilus-shell-squid-gladius-or-similar-structure-eventually-form-the%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown





















































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown

































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown







Popular posts from this blog

"Incorrect syntax near the keyword 'ON'. (on update cascade, on delete cascade,)

Alcedinidae

RAC Tourist Trophy