I've been surveying for Purple Sea Snails (Janthina umbilicata) and encountered some washed up this morning (5 March 2024). Janthina is rare in our area, and these snails were still alive, so I took a few photos for the record.
Remember that these snails float upside down at the surface of the ocean, hanging from their own bubble raft! So these photos show the snails suspended below the surface of the water.
Above, note the bifurcate or forked tentacles, with one long and one shorter branch (highlighted with black pigment).
Next -- look for the large, rounded, black foot. Janthina reaches up to collect a pocket of air and then surrounds it with mucous to create a bubble to add to its raft:
They also use their foot to smooth the bubble raft:
Janthina is a predator, feeding on By-the-wind Sailors (Velella velella) and Portuguese Man O' War (Physalia physalis) when available. They have a tubular proboscis to reach out and grab prey, and a rasp-like tongue (radula) at the end of the proboscis:
P.S. If you happen to see Purple Sea Snails washed up on the beach this spring, I'd love to hear about your observations!
4 comments:
This planet of ours sure makes some interesting creatures.
Hi, John!
Right? So many questions about so many species!
:) Jackie
Yes! I have seen them on Pebble Beach at Sea Ranch mostly after large storms. All the ones I saw had animals in them, so I tossed them back in the ocean. All were tiny…except for one that was the size of the nail on my pinky finger. Marilyn 707-785-2019
Hi, Marilyn!
Just wanted to say thank you for this report from Sea Ranch. If you see Janthina again, I'd be very interested in a photo (if possible) and any other info, e.g., the date and approximately how many you observe.
Thanks again, it's very helpful to hear about sightings in the northern part of the county!
Best,
Jackie
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