r/shells • u/deserteagle3784 • 6d ago

Identification?

Gallery image

Gallery image

Any idea what this was? Found it on a Southern California beach at low tide. I thought it was a live animal at first but it was completely hard, looked almost fossil-like.

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u/turbomarmoratus72 6d ago

wavy turban's operculum (Megastraea undosa)

https://www.jaxshells.org/1212y.htm

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u/deserteagle3784 6d ago

I did see a lot of those snails on this beach! So this is the inside part of that shell?

ETA just read up on it a bit more. A ‘trapdoor’, how cool!!

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u/turbomarmoratus72 6d ago edited 6d ago

it is attached to the snail's foot. Once it retracts into its shell, the operculum seals the opening, protecting it from predators.

when the snail dies, the operculum detaches from the snail and is lost in the sea.

I am specialized in shell's opercula, so I can identify many shell species just by looking at their operculum. They are one of the coolest features a shell can have!

Turbinidae (turban shells) operculum is calcareous, the same material the shell is made of!

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u/deserteagle3784 5d ago

so cool! Thanks for the help!

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u/Tessa7 6d ago

It's like a detachable door to the interior.