On the half shell

 

 

So we were walking at Dillon Beach this week and Eric looked down to see this large clam shell wedged in the sand under water.  It wasn't completely white inside, so he was curious about what looked like tiny yellowish dots in the center of the shell.

 

He picked up the shell and I took a look with my hand lens, but I couldn't tell what they were.  I couldn't even tell if they were hard (with a shell) or soft (gelatinous).  But Eric wiped his finger over a few of them and realized they were soft.  Hmmm...were they egg masses of some sort?

 

But because we couldn't see any detail, we decided to scoop up some seawater to fill the clam shell and see if any other hints would be revealed.

 

We were a little surprised, but here's what we saw next:

 

 

Tentacles!  It might be hard to tell from the photo, but we actually couldn't see the tentacles themselves.  They were too small and didn't stand out from the white shell in the background.  It was the shadows cast by the tentacles that were most apparent.  Here's a closer view:

 

 

 

The tentacles made the answer easier.  These are tiny jellyfish polyps.  You might remember that I posted about some different polyps on the docks in Bodega Harbor in late June — see "Soon to be jellies?" on 29 June 2023.

This is the first time we've observed jellyfish polyps on a clam shell.  It's likely we've just missed them, but now we'll know to watch for them.

 

 

The polyps need to attach to a hard surface, so on a long sandy beach, a clam shell might be prime real estate!

Soon to be jellies?

 

 

Once again Eric and his summer students found some beautiful jellyfish polyps in Bodega Harbor.  This photo is from 28 June 2023.

 

I shared more information about these polyps and an example of a jellyfish life cycle back in 2020.  Check out the post called "The polyp that packs a wallop".

The hydroids are lovely

  

Three-lined Nudibranch (Coryphella trilineata) strolling among a forest of Orange Hydroid (Garveia annulata) polyps.  Photographed in the low intertidal zone on 14 July 2022. 

P.S.  I couldn't help hearing the Robert Frost poem when I looked at this photo, but instead of "The woods are lovely, dark and deep..." I heard hydroids instead of woods!

Ethereal

 

 

It's a good time of year for jellyfish polyps in Bodega Harbor.  Eric captured these ethereal images on 6 March 2022.  

To learn more about these polyps and how they fit within the jellyfish life cycle, check out the post called "The polyp that packs a wallop" on 25 February 2020.

 

 

 Many thanks to Eric for sharing these beautiful images!

Reaching out

  

I'm running out of time tonight, but here's a nice photo that Eric took tonight — a microscope view.  

For a hint about what these are, check out this post from 25 February 2020.

The polyp that packs a wallop

Okay, here's the follow-up to last night's post, "The little one with the long tentacles."  

Below is another photo showing a different individual, but the same type of animal:

 

And here are two close-ups showing the stinging tentacles, and a view of the mouth area in the middle of the ring of tentacles:

 

 

The stinging tentacles are a clue that this is a cnidarian (i.e., the group that contains jellyfish, sea anemones, corals, etc.).  But which one is it?

Because this stage of the life cycle is so small (only a few millimeters long), many people haven't seen it before.

These are jellyfish polyps (also known as scyphistomae)!  Eric found them growing on sea squirts at the Spud Point Marina docks.  

Referring to the diagram below, the basic life cycle goes like this: free-swimming adult medusae release gametes (eggs or sperm); a fertilized egg develops into a planula larva; the planula eventually settles and undergoes metamorphosis into a benthic (bottom-dwelling) polyp; the polyp eventually undergoes fission — i.e., it buds off tiny juvenile medusae (called ephyrae) that eventually grow into the adults to complete the life cycle.

 

Modified from:  Living Invertebrates by Vicki Pearse, John Pearse, Mildred Buchsbaum, and Ralph Buchsbaum.  1987.  Blackwell Sci. Pub. and Boxwood Press.

In the image below, the polyp might be in the early stages of strobilation (note the banding pattern in the polyp):

 

And here's one more showing the beautiful but deadly tentacles (at least to tiny, microscopic prey):

 

P.S.  I'm not sure which species of jellyfish this is, but perhaps someone will recognize it and let us know.