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Crystal Cove State Park, Newport Beach, Orange Co., CA, March 6, 2026

We arrived at Crystal Cove State Park at 1 pm, when not much intertidal was exposed because the lowest tide level was not until 4:30 pm, and by then we were leaving. We still had plenty to see in the meantime.	-	A whimbrel is the most widespread species of shorebirds known as curlews within the sandpiper family. According to Audubon's online bird guide, they nest in the Arctic and winter on the shores of six continents.
I reached as far as I could with my camera set to use flash into a small cave depression on the side of a large rock reef at a high to mid tide level, the same rock where students were attempting to identify as many mollusk species as they could. They missed this one, living along the angled crease line in depressions with a low ceiling. This is a true pulmonate limpet, Trimusculus reticulatus (button shell). This is a quite sedentary suspension feeder, extending a string of mucus to capture floating plankton.	My students are busy attempting to identify mollusk species on a rock while we wait a few hours for the tide to get its lowest. At this tidal level there were of course littorines, about eight species of limpets, three mussel species, three chiton species, snail predators (especially Acanthinucella spirata or angular unicorn snail).	-
-	-	This juvenile blue-banded hermit crab (Pagurus samuelis) was observed inside one of two purple snail shells found together from juvenile ocean-drifting snails that have drifted into this southern California shore. The snail shells belong to the genus, Janthina, which includes multiple similar appearing species, altogether including nine accepted species at the Molluscabase.org website. They all are a similar color and tend to have a broad global distribution in tropical or near tropical oceanic regions. At this same beach last year we found an adult identified as Janthina exigua Lamarck, 1816 by snail experts, Ed Petuch and Ron Noseworthy. I would guess these juveniles are from the same species, which has a more pronounced sinus on the lip of the shell than other congeners.
Beu's (2017) masterful monograph on Janthina and a related genus can easily be found on the web and is open access. Janthina spp. snails float passively as members of the oceanic neuston community at the surface of the ocean, feeding mainly on two genera of cnidarian chondrophores. The first of these is the by-the-wind sailor Vellela vellela, familiar to Californians because it sometimes washes up in large numbers on California shores. The second belong to the chondrophore genus, Porpita, which does not wash up in California.	-	Here, the white shell, also with a juvenile blue-banded hermit crab, was confusing for me to identify because it was so thin and translucent that I could see the body of the hermit crab. I have tentatively identified it as a common resident snail, Opalia funiculata (sculptured wentletrap), which in life has a more solid shell. Like Janthina, it is a member of the caeogastropod family, Epitoniidae. I have noticed that shells of this family tend to break down in proteinase treatment associated with DNA extraction, which I think is unusual for snails, so I am guessing that the shell was originally more solid.
Intertidal wentletrap snails in California, Opalia funiculata and another species we saw, Epitonium tinctum are ectoparasites, attaching and feeding at the base of much larger anemones. They have an interesting connection to the oceanic species of Janthina, which feed on floating cnidarians. At some point, the common ancestor of the snail lineage leading to living species of Janthina evolved a floating solution to enable their drifting lifestyle by inflating their normal epitonid egg case to also function as a floatation device. This keeps them at the ocean surface. For more details, see Cecilia Churchill et al. (2011. see Current Biology Vol 21 No 19 R802).	I have noticed that despite its white shell, something quite surprising happens when our resident wentletrap snails, Opalia funiculata and Epitonium tinctum, are placed in ethanol. The solvent will quickly turn from clear to a similarly lovely lavendar color that is similar to the shell of all species of Janthina.	-
A Spanish shawl nudibranch (Flabellinopsis iodinea) gets its bright colors (orange cerata, scarlet rhinophores, and purple body) by its only prey, the hydroid Eudendrium ramosum. The pigment astaxanthin it gets from the hydroid is different colors in the different molecular states it is found in this sea slug.	-	-
The jewelbox clam (or reversed chama), Pseudochama exogyra, was common in the intertidal.	-	I have seen multiple anemones over the years at Crystal Cove State Park that are difficult to identify. Here is another. Is this Anthopleura artemesia or something else?
-	-	In a 2024 paper published in Molecular Phylogenetics and Evolution (107990), Sophio Paz-Sedano and coauthors (including West Coast nudibranch guru, Terry Gosliner) have once again changed the generic assignment for our Hopkins rose nudibranch, changing now to Ceratodoris Gray, 1850, a genus that currently has 24 accepted species. This typical pink nudibranch is now Ceratodoris rosacea (MacFarland, 1905), whereas it was previously assigned to Okenia Menke, 1830, which now has only 18 accepted species. The common name as many of us still remember refers to the new genus introduced when it was first described, Hopkinsia MacFarland, 1905, named for the oldest West Coast marine lab, Stanford's Hopkins Marine Station.
-	Similar to the Spanish shawl nudibranch discussed above, the Hopkins rose nudibranch (Ceratodoris rosacea) gets its striking pink color from a carotenoid pigment still (haha) known as hopkinsiaxanthin. As in the Spanish shawl nudibranch, they get the pink (or rose) color from their favorite diet, but in this case it is a pink encrusting bryozoan, Integripelta bilabiata. It is thought that the bright appearance is an aposematic warning signal, announcing to potential visual predators that the nudibranch will taste disgusting if they choose to try eating it.	This California scorpionfish (Scorpaena guttata) my students observed in a tidepool, is a large venomous sculpin found from central California to the Gulf of California in Mexico. In 1951, Halstead called it one of the most noxious marine animals in California waters and it has been resposible for numerous fishing-related injuries over the years. Spines each have two longitudinal grooves filled with tissue that secrete the cardiotoxic venom released into anyone pierced with these spines when a membrane sheath is pushed back exposing the venom into the unfortunate victim.

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