# Help me identify this sea creature

**URL:** <https://boards.straightdope.com/t/help-me-identify-this-sea-creature/440287>\
**Category:** Factual Questions\
**Created:** [March 6, 2008, 4:19am UTC](https://boards.straightdope.com/t/help-me-identify-this-sea-creature/440287 "2008-03-06T04:19:09Z")\
**Posts on this page:** 10\
**Page:** 2

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**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\
**Post date:** [March 7, 2008, 12:01am UTC](https://boards.straightdope.com/t/help-me-identify-this-sea-creature/440287/21 "2008-03-07T00:01:16Z")

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[QUOTE=Contrapuntal]  
Is it the dying that does that?  
[/QUOTE]

I expect so - they should look something like this when they’re alive:  
[![](https://starthrower.org/products/DDDB/DDDB_050-099/DDDB%20077%20chitons.jpg) ](https://starthrower.org/products/DDDB/DDDB_050-099/DDDB%20077%20chitons.jpg)

Looks like either the top surface of these specimens has shrivelled, pulling the mantle up and around, or the soft body parts have swollen.

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**Author:** ![Great\_Dave](https://avatars.discourse-cdn.com/v4/letter/g/46a35a/32.png) [@Great\_Dave](https://boards.straightdope.com/u/Great_Dave)\
**Post date:** [March 7, 2008, 4:45am UTC](https://boards.straightdope.com/t/help-me-identify-this-sea-creature/440287/22 "2008-03-07T04:45:07Z")

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Nope, it’s right side out.

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**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\
**Post date:** [March 7, 2008, 8:51am UTC](https://boards.straightdope.com/t/help-me-identify-this-sea-creature/440287/23 "2008-03-07T08:51:22Z")

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[QUOTE=Great Dave]  
Nope, it’s right side out.  
[/QUOTE]  
Ah. Are the plates internal in the gumboot chiton? (I thought they were on the back like other species). In that case, are we looking at the internal plates up through the (emptied) body cavity?

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**Author:** ![Great\_Dave](https://avatars.discourse-cdn.com/v4/letter/g/46a35a/32.png) [@Great\_Dave](https://boards.straightdope.com/u/Great_Dave)\
**Post date:** [March 7, 2008, 2:25pm UTC](https://boards.straightdope.com/t/help-me-identify-this-sea-creature/440287/24 "2008-03-07T14:25:51Z")

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Must be. Whenever I’ve seen them undewater, they look like the photos- pinkish orangey, and soft and rubberlike.

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**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\
**Post date:** [March 7, 2008, 2:31pm UTC](https://boards.straightdope.com/t/help-me-identify-this-sea-creature/440287/25 "2008-03-07T14:31:45Z")

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[QUOTE=Mangetout]  
I expect so - they should look something like this when they’re alive:  
[![](https://starthrower.org/products/DDDB/DDDB_050-099/DDDB%20077%20chitons.jpg) ](https://starthrower.org/products/DDDB/DDDB_050-099/DDDB%20077%20chitons.jpg)

Looks like either the top surface of these specimens has shrivelled, pulling the mantle up and around, or the soft body parts have swollen.  
[/QUOTE]

What species are those? They appear not to be gumboot chitons.

While I don’t have personal experience with the species, sources indicate that the gumboot chiton is unusual in that the mantle normally covers the back plates, as shown in the pictures previously linked to. In most other chitons, the plates are exposed.

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**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\
**Post date:** [March 7, 2008, 2:33pm UTC](https://boards.straightdope.com/t/help-me-identify-this-sea-creature/440287/26 "2008-03-07T14:33:39Z")

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[QUOTE=Colibri]  
What species are those? They appear not to be gumboot chitons.

While I don’t have personal experience with the species, sources indicate that the gumboot chiton is unusual in that the mantle normally covers the back plates, as shown in the pictures previously linked to. In most other chitons, the plates are exposed.  
[/QUOTE]

It looks like my image search misleaded me - I didn’t realise the gumboot chiton’s plates are internal.

So it looks like the OP’s pictures consist of the remains of one from which the internal organs are missing.

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**Author:** ![ShadowFacts](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/shadowfacts/32/2934_2.png) [@ShadowFacts](https://boards.straightdope.com/u/ShadowFacts)\
**Post date:** [March 7, 2008, 8:46pm UTC](https://boards.straightdope.com/t/help-me-identify-this-sea-creature/440287/27 "2008-03-07T20:46:04Z")

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[QUOTE=Mangetout]  
They have a radula (essentially a tongue) tipped with a rasp composed of magnetite.

The specimens we’re seeing in the photos here are turned almost inside out - in life, they look like a hard wavy, stony plate (visible as the tooth-like scales inside the cavity in the pictures) with a thick rubbery sole (which is the soft body parts of the animal).

Think of it as a very substantial slug with a shield-like plate on its back.  
[/QUOTE]

Fascinating. Thanks!

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<div class="post-metadata">

**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\
**Post date:** [March 7, 2008, 10:31pm UTC](https://boards.straightdope.com/t/help-me-identify-this-sea-creature/440287/28 "2008-03-07T22:31:46Z")

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Should be noted that everything past the first sentence in that quoted post is incorrect, **ShadowFacts** - due to my misunderstanding of the anatomy of this organism. The magnetic teeth thing is, as far as I can tell, correct.

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**Author:** ![sjc](https://avatars.discourse-cdn.com/v4/letter/s/e5b9ba/32.png) [@sjc](https://boards.straightdope.com/u/sjc)\
**Post date:** [March 8, 2008, 12:45am UTC](https://boards.straightdope.com/t/help-me-identify-this-sea-creature/440287/29 "2008-03-08T00:45:50Z")

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I immediately identified it as a chiton, we have them in our area.

Don’t know which species though.

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**Author:** ![Great\_Dave](https://avatars.discourse-cdn.com/v4/letter/g/46a35a/32.png) [@Great\_Dave](https://boards.straightdope.com/u/Great_Dave)\
**Post date:** [March 9, 2008, 12:15am UTC](https://boards.straightdope.com/t/help-me-identify-this-sea-creature/440287/30 "2008-03-09T00:15:18Z")

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[QUOTE=Mangetout]  
Should be noted that everything past the first sentence in that quoted post is incorrect, **ShadowFacts** - due to my misunderstanding of the anatomy of this organism. The magnetic teeth thing is, as far as I can tell, correct.  
[/QUOTE]

Don’t be too hard on yourself- you describe other species of chiton in that quote, just not this particular one.

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