The next day, I promised to tell the full story about this animal. Well, it turned out to be a bigger mystery than we first anticipated. I don't have enough time tonight to reveal all of the details, but I thought it would be fun to share at least part of the story (and more pictures!).
If you follow this blog, you might have guessed that this is a staurozoan, sometimes informally called a stalked jelly. [See previous posts about staurozoans on 13 July 2017, 25 May 2013, and 12 November 2012.] Below you can see the entire animal, with the stalk attached to a blade of algae. This individual is ~25 mm long.
Staurozoans are predators, capturing small crustaceans (e.g., amphipods) with their stinging tentacles. Here's a close-up of one arm with the beautiful (but deadly) tentacles:
While observing these staurozoans, we noticed an individual with an amphipod deep inside the calyx (the cup-like portion of the staurozoan). Can you find the pink amphipod in the photo below?
One time we saw a staurozoan capture an amphipod that swam a little too close to the tentacles:
The unanticipated and exciting part of this story is that we are not sure which species this is. It appears that it could be a staurozoan not previously known from California. We are continuing to work with a team of experts to try to figure it out. I'll provide additional information and we'll share more as the mission unfolds.
And I'll end with a bonus. Eric captured some very nice video, so here are some short clips of two individuals: