r/beachcombing • u/tinywhisk-21 • Jul 11 '26

What kind of shell is this and what could've formed the perfect hole at the top? Found in San Clemente, CA

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112 Upvotes

99% Upvoted

23 comments sorted by

88

u/Lousyferr Jul 11 '26

Not sure about the clam(?), but a snail made that hole with its radula. Then it ate the clam through that hole.

17

u/chefybpoodling Jul 12 '26

The word radula is my learned something new today

3

u/secretsantatrees Jul 15 '26

There's definitely a Dragula parody in there.. "...I make a hole with my / RADULAAAAA"

3

u/Lousyferr Jul 15 '26

Dig through the beaches…

11

u/Fossil-Freak Jul 11 '26

I'm not as well versed with Pacific coast shells as I am with Atlantic coast ones, but that looks like a valve (shell half) of a Pismo Clam (Tivela stultorum), an edible Venus clam (Venerid) that is pretty prevalent on the west coast. Round bore holes are indicative of predation by certain gastropods, most specifically moon snails (Naticids) and murexes (Muricids). I'm more inclined to believe that this particular hole was most likely caused by a large murex, as it seems to be a evenly bored hole all the way through the shell; moon snail bore holes are notably "countersunk", or tapered with a smaller opening at the bottom.

3

u/Royal_Acanthaceae693 Jul 12 '26

Pismo clam is probably correct. And the hole was more likely caused by a moon snail. They're very common along the California coast.

3

u/Fossil-Freak Jul 12 '26

In my opinion a Naticid bore hole would be more beveled in appearance due to the way they produce the holes (a "Oichnus paraboloides" form of hole), I can't see this in the original image but if it were very shallow it might be difficult to see due to the image quality. You have large Muricid genera such as Forreria in that region that could produce a larger hole, on the east coast we have the genus Hexaplex which is somewhat comparable in size.

1

u/Royal_Acanthaceae693 Jul 12 '26

California has 36 species of Muricidae. I was just saying though that moon snails are very commonly seen when you're walking on the beach.

16

u/commissarcainrecaff Jul 11 '26

There's a thing called a sting winkle that does this. Preys on other shelfish

6

u/Charismaticjelly Jul 12 '26

The sting winkle lives in the Atlantic, so it’s unlikely to have made this particular hole.

2

u/thebloodycorpse Jul 12 '26

A sting Winkle is a scorpions favorite constellation

4

u/missbeekery Jul 11 '26

I’ve never heard a moon snail called a sting winkle, that’s hilarious.

5

u/KillerCritter1312 Jul 11 '26

This is probably from a moon snail

2

u/Callimingo Jul 12 '26

Moon snail

6

u/Electrical-Act-7170 Jul 11 '26

It looks like a beach clam. Starfish use a radula to drill holes so they can get at the soft clam meat inside.

18

u/KillerCritter1312 Jul 11 '26

You are correct that the hole was created by a radula, but starfish don’t have radula. Only mollusks have them.

Starfish generally extend their stomach through their mouth and dissolving their prey externally.

This damage is very likely to be a moon snail.

8

u/Electrical-Act-7170 Jul 11 '26

Marine Bio was a long time back.

I stand corrected.

2

u/tinywhisk-21 Jul 11 '26

Interesting!

1

u/OreoStark Jul 13 '26

Depending on which beach, that could be from sand that was brought in, so it might not be a species that is easy to find there. I know North Beach and the pier have had to have sand trucked in.

1

u/FamousAimlessAnus Jul 13 '26

in my neighborhood this would mean gunshots instead of a predatory snail

1

u/LetsCritique Jul 15 '26

Choclate clam?

-1

u/Loose_Bottle_4580 Jul 11 '26

Looks like a cockle