Christmas bell

  

We had our Christmas dinner and celebration mid-day, so we couldn't resist a late afternoon trip to the coast including some tidepooling on the extreme low tide.

One of the most exciting finds during our exploring was a beautiful staurozoan, Manania gwilliami.  This individual was ~2 cm tall.

Staurozoans are also known as stalked jellyfish because their body plan resembles the bell of a jellyfish attached to the rock with a stalk.  The edge of the bell is armed with clusters of stinging tentacles used to capture prey including small crustaceans:

 

 

Although this staurozoan was in a channel with water surging back and forth, Eric managed one photo from below showing the swirling red and white color pattern on the inner surface of the bell:

 

 

 

Manania gwilliami photographed in the low intertidal zone in Sonoma County on 25 December 2022.  (With many thanks to Eric for spotting and photographing this beautiful staurozoan!)

 

P.S.  To learn a little bit more about this species, see the post called "Twinkle, twinkle little stauro" on 12 November 2012.
 

Stauro Trek: A continuing mission...

Several days ago, on 1 September, I showed this mystery photo:

 

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:

Haliclystus sp Bodega Bay from Jackie Sones on Vimeo.

Stay tuned!

P.S.  Many thanks to Malina for spotting these staurozoans!

Stauro-gazing

 

Not much time tonight, but I think you can see why I couldn't resist sharing this photo.  It's one of my favorites of the year!

If you've been following this blog for a while, you might have seen this species before, but it's been several years.  This is Manania gwilliami, a beautiful staurozoan. [Staurozoans are now a separate taxonomic class within the cnidarians.  Sometimes they're informally called stalked jellyfish.]  It was found locally today in the rocky intertidal zone.  We didn't measure it, but estimate it was ~12 mm long.

Here's the entire animal:

 

This individual had beautiful purple highlights.  Check out this close-up of two tentacle clusters:

 

When looking at the tentacles, I noticed some whitish pads at the base of some of the tentacles.  Here's one view:

 

After doing some research, I learned that these are adhesive pads.  It is hypothesized that when the staurozoan releases its pedal disc (the base of the stalk) from the substrate, it sometimes holds on with these pads while it reattaches.  Since I haven't been able to find many pictures of these interesting structures, here's one more image.  Look for the swollen white areas at the bases of the front three tentacles:

 

I'm sharing these staurozoan photos with you thanks to Hao Hao, one of Eric's summer students at the marine lab.  Her curious eyes spotted it attached to a blade of algae in the intertidal zone.  Thanks, Hao Hao!

P.S.  For an introduction to staurozoans, review the post called "Twinkle, twinkle, little stauro" from 12 November 2012.

Consolation prize

Well, we didn't find what we were looking for today, but near the end of our search at Eagle Cove on San Juan Island, Eric looked down into a tidepool and found this!

 

This is a stauromedusa.  It's about 1 cm across and attached to a piece of red algae (Mazzaella sp.).  We think it's a species of Haliclystus.

Here's a view from the side:

 

I don't have many resources with me, so will have to do more research on this species when I return to California.  For now here are a few more pictures of this wonderful animal.

 

 

The next image shows the stauromedusa holding a crab zoea (larva) that it had just captured.  You can see the crab zoea's eyes and its spine pointing backwards.  I don't know how often stauromedusae eat crab zoeae, but this one caught at least three while we were watching it today.

 

I first wrote about stauromedusae in November, so click here to review their anatomy and a little bit about their biology and read more about a different species that we found on Bodega Head last fall.

Twinkle, twinkle, little stauro

 

Today, Eric's sharp eyes found one of the most intriguing intertidal inhabitants of Bodega Head.  This is a little-known marine animal called a stauromedusa.  They're cnidarians, related to jellyfish, sea anemones, and hydroids.  Most of them are very small (a few centimeters tall) and cryptic (blending in with algae or seagrass), so they aren't encountered often.  [The one in these photographs is ~1 cm tall and is attached to coralline algae.  It was found in a wave-exposed surge channel.]

Several features stand out.  Note the long, flexible, contractile stalk.  Stauromedusae often stay in place, but they can also let go and move around.  Here are two views of the stalk when extended and pulled in (below). 

 

Opposite the disc is a large bell-shaped calyx.  To make it easier, review this illustration and then search for the features in the images.

 

Illustration modified from the following:  Larson and Fautin, 1989.  Stauromedusae of the genus Manania (= Thaumatoscyphus) (Cnidaria, Scyphozoa) in the northeast Pacific, including descriptions of new species Manania gwilliami and Manania handi.  Canadian Journal of Zoology 67: 1543-1549.

The calyx has eight clusters of short tentacles surrounding the mouth.  The tentacles contain cells with nematocysts (tiny harpoons) for capturing prey such as copepods and amphipods.

In between the tentacle clusters are small anchors.  The anchors are useful for reattaching (if the disc becomes detached) and may aid in securing food.

 

The white and brown zigzag markings running between the stalk and the tentacles are reproductive structures or gonads.

 

We believe this is Manania gwilliami.  It was first described in 1989 and named after G.F. Gwilliam — an early graduate student of Cadet Hand (the first director of the Bodega Marine Laboratory) and one of the first people to study stauromedusae in the eastern Pacific.

Manania gwilliami occurs along the Pacific Coast from British Columbia to Baja California (records from Oregon and Washington are apparently lacking, but it's likely that the species is found there).  It prefers surf-swept rocky outer coasts.

When I first learned about stauromedusae they were thought to be most closely related to jellyfish (visualize a tiny, upside-down jellyfish on a stalk).  But recent molecular studies have suggested that they belong in their own class, Staurozoa (Collins and Daly 2005).

We've been wanting to find a local stauromedusa for a long time.  What luck to find our first one on Bodega Head on a beautiful November afternoon!

 

You can learn more about stauromedusae at the Encyclopedia of Life web pages.