A clam like no other

 

 

I looked down to see this distinctive shell washed up at Point Reyes this past weekend (23 August 2025).  Note the elongate shape and the fine ridges radiating from the hinge (the hinge is at the bottom of the photo).

 

I posted briefly about this species back in 2015 (See "File this away" on 28 June 2015), but it's rare to observe Hemphill's File Clam (Limaria hemphilli) in our region, so I thought it would be worth sharing another record.  Limaria hemphilli has a more southern distribution, with most records south of Point Conception (and only a few records north of Monterey).

 

I also remembered that Sam documented a file clam in Bodega Harbor in 2024.  He was lucky to find a live individual and he captured the beautiful and intriguing tentacles.  Check it out!

 

 

 

 

Here's an even closer view of those amazing tentacles:

 

 

 

The tentacles are extensible -- they can stretch out far away from the shell.  And interestingly, there are reports of predators being distracted by tentacles that have been dropped, so at times the tentacles might be used to deter predation (somewhat similar to a lizard's tail).

 

With many thanks to Eric for the photo of the shell and to Sam Briggs for the spectacular photo of the live file clam. 

Greenery

Sola green (tentacles of the Sunburst Anemone, Anthopleura sola):

 

 

 

Sculpin green:

 

 

 

 

Siphon green (clam siphon):

 

 

 

Red end of the spectrum

There's a lot of red in the intertidal zone, along with pinks and oranges and golds at that end of the color spectrum.  Sometimes it's fun to scan across different species to see the color similarities.  Here's a little tour from a recent outing:

 

 Fish eggs

Aldisa sanguinea (nudibranch)

 

Peanut worm (Themiste sp.) tentacles

Clam siphons

 

 

Veiled Chiton (Placiphorella velata) in hunting position

 

Juvenile Red Sea Urchin (Mesocentrotus franciscanus)

A clam, a sea squirt, and a snail

Well, I didn't get a chance to take any photos today, so I browsed through photos from the last month or so (from various locations) and picked a few that caught my eye.  I hope they brighten your day!

 

Juvenile Pacific Razor Clam (Siliqua patula)

 

A golden colonial tunicate (sea squirt), Pycnoclavella stanleyi 

 

Red Turban Snail (Pomaulax gibberosus) with coralline algae

P.S.  What did the clam say when the sea squirt and the snail walked into the bar?  "Sorry, I'm just about to close up for the night."  :)

Rose-painted

 

Rose-painted Semele (Semele rubropicta), photographed in Bodega Bay on 21 March 2017.  It was ~3 cm (a little over an inch) long.

Note the small circular hole — evidence that this clam was drilled by a predator.

 

File this away

We haven't done a mystery close-up in a while.

Can you guess what this is?

 

It looks like a series of waves running towards the shore, doesn't it?

Here's another clue:

 

And this one will help a bit more:

 

It still might be hard to tell what type of animal this is.

You're seeing extreme close-ups (under the microscope) of a shell.

I'm guessing it will be difficult to identify the type of shell, so the next photo will reveal the entire shell as I found it on the beach:

 

There are a few things that stand out about this clam.  It has a very oblong shape; it has narrow ridges that look like rays running towards the edge of the shell (more prominent near the margins); and it's very thin and fragile.  (Yes, it's broken, but it's still worthy of sharing because it's a rare clam in this area!)

Meet Limaria hemphilli.  I've seen various common names for it, but I think my favorite is Hemphill's File Clam.  It was named after Henry Hemphill (from San Diego), who did a lot of the early work on molluscs in California...and its ridges give it a file-like appearance.

Limaria hemphilli is more common south of Monterey.  In fact, most books list Monterey as its northern limit.  But we've seen at least four individuals in Bodega Bay during the past ten years.  I hope to photograph one alive some day — they're quite spectacular with many long tentacles reaching far beyond the shell.  And they have interesting behaviors — they make "nests," and they swim like scallops!

P.S.  If you're curious, there's a nice picture of a live Limaria available here.

It takes two

 

I know, it's been way too long since I've posted a picture of clam siphons.  ;)  At least that's what Tim would say!

I photographed these siphons in a rocky crevice at low tide this afternoon.  They were under water at the time.  Do you remember which is the inhalant siphon (pulling water in) and which is the exhalant siphon (pushing water out)?

 

The siphon on the left, with all of the frills, is the inhalant siphon, while the siphon on the right, with the more volcano-like opening, is the exhalant siphon.

I showed a clam similar to this on 9 August 2013, but those pictures were taken under a microscope (click here to review them).  I thought it would be worthwhile to show you what the siphons would look like if you encountered them along a rocky shore.

Although I'm not sure 100% sure, this might be a Flat-tipped Piddock (Penitella penita).  But let me know if you think it could be a different species.

 

The Rook and the Nozzle

Okay, I'll admit it, that has to be one of the strangest blog post titles!  Are you curious about it?

It probably reveals too much about me.  Or maybe not.  In this case, it shows that I use analogies to learn about and remember things, which can be useful when exploring natural history topics.  (It also exposes my fondness for board games — I'm a poor chess player, but challenge me to a backgammon game and I'll do my best to make it interesting!)

Here's the Rook:

 

And here's the Nozzle:

 

Do you have a guess about what type of animal this is?  Here are the two parts as they appear together:

 

These are the siphons of a small clam.  The "rook" is the inhalant siphon and the "nozzle" is the exhalant siphon.  Clams often have frills surrounding their inhalant siphons to prevent entry of larger particles.  

The exhalant siphon has a thin membrane that appears to function like the nozzle on a garden hose.  This is helpful for jettisoning already filtered water further away from the animal so that it isn't sucked in again by the adjacent inhalant siphon.  (You probably have an intuitive sense for the physics involved — reducing the diameter of the end of the hose results in an increase in velocity of the exiting water.  Hmmm...this also reveals that I'm a fan of the occasional garden hose water fight!)

Here's a view of most of the clam with the siphons extended far beyond the shell:

 

And one of the clam out of the water so you can see the entire shell (which was ~15 mm long):

 

You've probably noticed that I've avoided identifying this clam.  That's because I'm not 100% certain of its identity.  It might be Hiatella arctica.  But if you have thoughts about the species identification, please let me know.

Finding frills in a boring animal

A mystery close-up for you.  Do you have a guess about what this might be?

 

Okay, here's another clue.  The next picture was taken under a microscope, but with less magnification.

 

Still need some help?  I'll zoom out a little more:

 

It might be difficult to make out, but you're looking down on the siphons of a rock-boring clam!  This is a Flat-tipped Piddock (Penitella penita).  The inhalant siphon is on the left and was the one featured in the first two photographs.  The frilly projections extending across the inhalant siphon act as a filter to keep out large unwanted debris.  The smaller exhalant siphon is on the right and has a smooth opening.  [The frill is gone.]  The entire width of the two siphons in the view above is about 15 mm across.

Flat-tipped Piddocks are probably more common than we think.  But because they're hidden in burrows in the rock, the clams themselves are generally not that visible.  The siphons are beautiful, but you'd have to be looking in a pool or under water to find and appreciate them.

This clam happened to be on the edge of a rock that collapsed, so it became exposed and it seemed like a good opportunity for a photograph of this seldom-seen animal.  

The clam has a somewhat unusual shape (see below), with a very bulbous rounded end that sits at the bottom of the burrow and an elongated leathery portion that reaches to the surface of the burrow.  Look for the many rough lines of "teeth" on the outer surface of the shell.  The clam uses these teeth to rasp away at the rock.  It rocks back and forth, moves up and down, and rotates around and around, to create a long, smooth, circular burrow.  (You may occasionally discover these burrows in rocks washed up on local beaches!)

 

In-N-Out Bivalve

 

 Clam siphons 

I wish I knew which species of clam this is.  (It was found in a low intertidal cobble on 7 July 2012.)  But even without a name, it's easy to appreciate the attractiveness of this bivalve's siphons.  Can you tell which is the inhalant siphon (taking in water) and which is the exhalant siphon (expelling water out)?

Here's another view:

 

The exhalant siphon is smaller, with lobes along the fringe extending outward.   It's at the top of these photos.  The smaller diameter of the exhalant siphon increases the velocity of exiting water, thereby reducing the chance that the clam will draw in water that's already been filtered. 

The inhalant siphon is larger, with tree-shaped structures (sometimes called papillae) extending towards the center (especially visible in first photo).  The papillae help prevent larger particles from entering the siphon.

The clam and the tunicate

Here's a photo from late February.  Recent stormy sea conditions made me wonder if more of these might have washed up on local beaches this week.

 

Two Sea Bottle Clams (Mytilimeria nuttalli) are embedded in a purple tunicate (possibly Cystodytes lobatus?).  Normally the clams are completely covered by the tunicate, but here a portion of the tunicate has been torn away, revealing the clams below.

Unlike most clams that live in sandy or rocky substrates, Sea Bottle Clams are usually found living within tunicates (in the low rocky intertidal zone or shallow subtidal areas).  While most of the clam is hidden below the surface, they can extend their siphons into the water through a small narrow slit in the outer covering of the tunicate to feed.

These clams may reach 4 cm in length, but individuals ~2 cm long are more common.  Their shells are quite thin and fragile — given protection by the tunicate, this clam doesn't need to produce a thicker shell.

The interior of Sea Bottle Clam shells is beautiful and often described as lustrous or pearly (see below).

 

Although not much is known about their life history, it's thought that juvenile Sea Bottle Clams attach to a tunicate with a byssal thread (like those used by mussels), and then the tunicate grows up around the young clam. 

ADDENDUM (30 March 2012)

Sure enough, during a quick walk on the beach this morning I encountered a few more Sea Bottle Clams.  Here are two shots from 30 March.  

The first shows the slit through which the siphons are extended (as well as a smaller clam to the right of the slit).  The second is another attempt to capture the polished interior (it's better to see this in the field!); it also shows how thin and fragile the shell it.

 

Type locality: Russian Bodegas...or, History in a clam shell

Is anybody else still amazed by the wonders of the Internet?  Today I was thinking that it would be fun to post some information about species that include "bodega" in their scientific names.  One example is a clam called the Bodega Tellin (Tellina bodegensis).  Here is a photo of it from Salmon Creek Beach taken on 21 February 2012, and a scan of another specimen.  Note the elongate shape and the narrow concentric striations.

 

 

I wanted to check on the origin of the name.  Where did "bodegensis" come from?

Through a book, I found that the Bodega Tellin was described by R.B. Hinds in 1845 in a report called The Zoology of the Voyage of H.M.S. Sulphur, Under the Command of Sir Edward Belcher, R.N., C.B., F.R.G.S., etc. During the Years 1836–1842.

I searched the Internet for the title of this report and was amazed to find a full electronic version.  It was easy to locate the description of Tellina bodegensis along with the plate containing an illustration (see below).  

 

 

 Tellina bodegensis is in the upper left corner.

It was very interesting to read the location for the collection (perhaps the type locality) listed as "Russian Bodegas".  The Russians didn't leave the Bodega Bay/Fort Ross area until 1841, and it's thought that they had a small settlement on the southern end of Bodega Head (near Campbell Cove).  It seems as though Richard Brinsley Hinds named the Bodega Tellin after collecting it at a depth of 7 fathoms (42 feet) on a sandy bottom near Bodega Head. [The name Bodega began to be associated with this area in 1775 when charted by the Spanish naval officer Bodega y Quadra.]

Fascinating to think about Hinds viewing Salmon Creek Beach or other nearby sites and describing a local clam for the very first time!

Salmon Creek Beach in the fog on 21 February 2012.

Duxbury Reef

An exceptional low tide (-1.7 ft.) at Duxbury Reef in Bolinas, CA, on 25 November 2011 revealed many interesting marine invertebrates:

A Sunburst Anemone (Anthopleura sola) with unusual bright lime-green coloration.

The siphons of two different piddocks or rock-boring clams.  Note the frilly openings to the inhalant siphons that act like sieves, allowing smaller particles through and keeping out larger particles.

Quite a few nudibranchs or sea slugs, including this colorful Sea-clown Nudibranch (Triopha catalinae).  This species eats branching, arborescent bryozoans.

A peanut worm (Phascolosoma agassizii) searching among purple urchins (Strongylocentrotus purpuratus).  This photo shows the striped introvert, or anterior portion of the worm; the peanut-shaped trunk, or main part of the body, is hidden from view.