Festive

  

Hard to believe another year has gone by.  Here are a few festive invertebrates from our tidepooling last week to help celebrate turning the corner into 2023.  Enjoy!

Above, a beautiful tubeworm, Serpula columbiana.  

Next, an unidentified sabellid worm:

 

 

A wonderful peanut worm, Themiste pyroides:

 

 

And to wrap it up, a colorful nudibranch, Triopha catalinae:

 

 

Best wishes for the new year ahead!

Peanut brittle?

  

Okay, I know I've shown a few peanut worms recently, but this was a nice view of several different peanut worms (Phascolosoma agassizii) extending their introverts from a crevice and using the short ring of tentacles at the end to feed.  You can also see several arms of a brittle star extending out of the crevice and even lying across one of the peanut worms.

P.S.  If you want to play the "phyla game" again, look around to see what you can find.  Below I'll list the phyla in this image.

1. Peanut worm (Phascolosoma agassizii), Phylum Sipuncula
2. Brittle star, Phylum Echinodermata
3. Barnacle, Phylum Arthropoda
4. Limpet (checkered, in lower left corner), Phylum Mollusca
5. Tube worm (orange tentacles, upper right corner), Phylum Annelida
6. Flatworm (gray/white, same species as last night), Phylum Platyhelminthes

Local diversity

  

Eric noticed a beautiful scene in the low intertidal zone a few days ago.  There are six (!) different phyla (major animal groups) represented in this image, all in an area that was only ~4 cm x 4 cm (or ~1.5" x 1.5").  

Feel free to look around and see what you can find.

In the next image, I've circled or pointed to representatives of each phylum.

 

 

Green arrow = sea anemone (Epiactis handi), Phylum Cnidaria
White circle = barnacle (Chthamalus dalli), Phylum Arthropoda
Blue circles = flatworms (unidentified), Phylum Platyhelminthes
Orange arrow = peanut worm (Themiste pyroides), Phylum Sipuncula
Purple oval = tubeworm tentacles (Phragmatopoma californica), Phylum Annelida
Pink arrow = chiton (Tonicella lokii), Phylum Mollusca

Tiers of tentacles

And two more to wrap up this series illustrating color variation in the tentacles of the tubeworm, Spirobranchus spinosus:

 

 

 

 

Photographed in the Carmel area on 26 February 2021.

 

Golden spirals

  

Another in the tubeworm series — this one with beautiful golden stripes and blue tips!  Spirobranchus spinosus photographed in the Carmel area on 26 February 2021.

P.S.  Refer to first post called "Magic blue spiral" on 27 February 2021.

Magic blue spiral

  

We were long overdue on a survey that we needed to get done in Monterey County, so we made a quick day-trip down to the Carmel area this week.  Thankfully, we were able to finish the survey in a few hours, and at the very end of it Eric spotted this beautiful tube worm in a tidepool.  Although time was short, he managed to take this wonderful photo.  Meet Spirobranchus spinosus!  This is a more southern species, but we'll be on the lookout to see if any show up in Bodega Bay in the future.

Isn't the blue color amazing?  The tentacles of this species aren't always blue, and I hope to show some of the color variation in another post.

Feather duster

 

Yes, you guessed it, another outstanding tubeworm.  This one is a Giant Feather Duster Worm, Eudistylia polymorpha.  It was also photographed in Monterey County on 31 August 2019.  You can find this species locally, although the individuals we see in Bodega Bay are more often a solid, deep red/maroon color.

Spiralling in

 

A beautiful tubeworm, Spirobranchus spinosus, photographed in the low intertidal zone in Monterey County on 31 August 2019.

 

Looking out

Below is a close-up mystery photo for you.  I know it might be challenging, but it's always fun to have a chance to wonder.  Can you guess what structures these are, or what type of organism it is?

 

If you're ready for another clue (or part of the answer), here's a photo showing a larger view:

 

The red mound-like structures in the first photo are compound eyes.  The eyes are located on the radioles (feeding tentacles) of the tube worm, Pseudopotamilla socialis.

July 1st is International Polychaete Day, so it seemed appropriate to highlight these amazing polychaete eyes!  (Polychaetes are segmented worms.)

Here's another view of the radioles of Pseudopotamilla showing the compound eyes:

 

The radioles form a fan or crown just outside of the worm's tube.  The radiolar crown is used for feeding (capturing food particles from the water) and respiration.  Because the compound eyes are found on the radioles, they're called radiolar eyes.

The eyes might serve primarily to detect shadows, so the worm can withdraw quickly into its tube (see below) when a predator (e.g., a fish) passes over.  It's also possible the eyes are involved in more complex visual processing, but further studies are needed.

 

Pseudopotamilla socialis lives in the low intertidal zone along our shores.  It's relatively small, but if you're looking very closely, you might catch a glimpse of its wonderful fan-like radiolar crown.  And if you see the crown pull back in, you'll know that it's possible that the radiolar eyes detected your presence!

Happy International Polychaete Day!

 

P.S.  Many thanks to Leslie Harris for confirming our identification.