Swirls above the sand

 

Yesterday I was helping Maddy and Eric look for ribbon worms on the tidal flats in Bodega Harbor.  I know, I was supposed to be looking for ribbons worms (and I did find some!), but I always get distracted when there are phoronids around.  Crowns of tentacles (lophophores) of Phoronopsis harmeri, Bodega Harbor, 20 July 2020.  [You can click on the image for a larger version.]

Let it shine

During this past week while conducting surveys in Bodega Harbor, I heard Eric say quietly, "You're not going to believe what I found."  I turned to look and could see this animal attached to the rock (it's ~3 cm wide):

 

The shells of these animals look like those of clams or scallops at first, but they have a distinctive shape that provides a hint that you're looking at something different.

This is the first time we've seen a live brachiopod in the Bodega Bay area.  Meet the North Pacific Lamp Shell (Terebratalia transversa)!  They're more common in deeper water (e.g., we've seen then come in on nets removed from Cordell Bank), but we found this one in the low intertidal zone.

Outwardly they look like bivalves, but internally brachiopods are more similar to phoronids.  Just like phoronids, they have a lophophore — a ring of coiled tentacles for feeding (see photos of phoronid lophophores here).  In brachiopods, the lophophore is not extended into the water, but is nestled between the two valves.  This body plan is unique, so these animals belong to their own phylum (Brachiopoda).

Here's another view:

 

P.S.  Brachiopods are sometimes called lamp shells because they're thought to resemble ancient Roman oil lamps.  Although you can't see it in these photos, one of the valves has a hole in it through which a stalk extends to attach to the rock.  The shape of the valve along with the hole look similar to a discus lamp with a hole for the wick (see examples here).

Out and about

A few weeks ago, I decided to try photographing some bryozoans in the field.  It worked pretty well, and the images were interesting enough that I'll likely try again. 

Bryozoans are colonial — it's possible you've noticed them growing as low rough patches on intertidal rocks or seaweeds.  But the animals making up the colony are pretty small, and are not easy to see with the naked eye (it's much easier to appreciate them under a microscope!).  

However, I tried using the "microscope mode" on my little waterproof camera in a shallow tidepool and you could see lots of feeding bryozoans with their bell-like tentacles extended into the water.
Here's an example of Derby Hat Bryozoan (Eurystomella bilabiata) from the field:

 

I've shown some microscope images of this species before, so if you'd like to compare (or to review introductory information about bryozoans), check out these earlier posts: "Pretty in pink" from 15 February 2012 and "Pretty in pink #2" from 1 July 2013.

Waking up with phoronids

 

I encountered some beautiful phoronids today.  Above is a close-up of Phoronis vancouverensis photographed on 17 July 2019.

And here's a group of individuals highlighting their graceful feeding tentacles:

 

I've written about phoronids before, but I can't help sharing photos of these wonderful invertebrates. 

For an introduction to (and more photos of) phoronids, you can review these previous posts:

"My, what a nice lophophore you have!" on 27 June 2013

 "Phoronids for the Fourth" on 4 July 2017

"Ebb and flow" on 26 July 2017

Fireworks

 

Seemed a closeup of a bryozoan colony would be an appropriate image for the 4th of July weekend — the open lophophores, or feeding tentacles, remind me of fireworks.

The lophophores can be completely withdrawn. The next two pictures are the exact same portion of the colony — the first shows the lophophores pulled in, the second shows most of the lophophores extended.  You can compare the positions of the spines to orient yourself within the colony.  

 

 

Speaking of spines, here's a little fact for you.  The units that support the lophophores are called autozoids.  But the units that produce the brown, chitinous spines are called kenozoids.  Below is a zoomed out picture showing more of the colony and more of the spines among the lophophores.

 

Above, you might have noticed that this bryozoan colony is growing on a piece of pink coralline algae.  This bryozoan species is also found growing on kelp.  When the waves are big, large Flustrellida spinifera colonies frequently wash ashore on local beaches and are often mistaken for algae.  You might have seen them before (next image), but perhaps you haven't had a chance to view their beautiful lophophores and intriguing spines under a microscope!

 

Pretty in pink #2

Several views of the bryozoan Eurystomella bilabiata, photographed under a microscope on 27 June 2013:

 

 

 

I first wrote about this species in February 2012.  For more information about it, and bryozoans in general, review that post here.

 

My, what a nice lophophore you have!

 

How many people get to start their day with a few nice images of phoronids?  You can count yourself among the lucky ones!

Phoronids are invertebrates related to bryozoans and are in their own phylum, Phoronida.  There are fewer than 20 described species in the world.  

These pictures were taken under a microscope on 27 June 2013.  The phoronids are Phoronis vancouverensis from the rocky outer coast.  

 

Phoronids feed with a crown-like structure called a lophophore.  Note the U-shaped indentation on one-side.  The tentacles are ciliated and actively draw water currents down through the lophophore to trap food particles.

 

For the record, we also noticed a few very small phoronids (see next image).  I'm not sure how old they are, but it's helpful to document when juveniles are present.  It might indicate the timing of larval settlement from the plankton.

 

P.S.  See the post from 27 November 2011 for a picture of Phoronis vancouverensis in the field.

P.P.S.  In February 2012, I shared images of Phoronopsis harmeri in Bodega Harbor and a little more general information about phoronids.