Leafy hornmouth and friends

Each critter that arrives in my aquarium, whether I brought it in on purpose, or it hitchhiked on seaweed or on a barnacle rock, or even if it was born in the tank, brings with it a responsibility. They each have their own specific diet to be provided, their own habitat needs; hiding spaces, climbing structures, sand or rocks, water currents and temperatures, company of their own sort. And providing those needs brings in more critters: the predators need prey, the gregarious ones need friends.

I don't know how the leafy hornmouth snail came to the tank. Maybe he arrived in a clump of mussels, brought in to feed the whelks. Or in a handful of seaweed. But he's here, and growing, (6.5 cm long now) and hungry. He eats barnacles and mussels, which means that I have to go shopping for barnacled rocks.

In between meals, he wanders around the glass walls.

Leafy hornmouth snail, Ceratostoma foliatum

Limpets travel on his back, and a family of orange-striped green anemones take advantage of the ever-changing currents; there's good eating in that water!

Foot and passengers

Spring is here. I guess I should be looking for a mate for him (or is it her? They know; I can't tell.)

One of the limpets. The yellowish blobs are limpet poop.

Empty snail shell with another orange-striped green anemone.

Next: leaving the tank behind and heading out into the forests again.

~~~~~~~~~~~

Cada animal que llega a mi acuario, sea como sea que llegue, trae una responsabilidad. Cada uno tiene su dieta preferida, sus requistos para el habitat: necesitan lugares para esconderse, estructuras donde pueden trepar, arena o piedras, corrientes de agua rápidos o suaves, temperaturas específicas. Los animales de rapiña necesitan su presa natural; las criaturas gregarias necesitan compañeros.

Y al traer lo que piden los habitantes del tanque, vienen otros animales, con sus propias necesidades.

No sé como llegó el caracol "leafy hornmouth" al tanque. Tal vez se escondió entre un grupo de bálanos; tal vez vino en una bolsa de algas de mar, traídas para comida de los cangrejos y ermitaños. Pero aquí está, creciendo rápidamente; ya mide 6.5 centímetros de largo. Y tiene hambre.

Come bálanos, mejillones y almejas, lo que me obliga a traer piedras cubiertas de bálanos y de mejillones de la playa para mantenerlo sano.

Cuando termina de comer, anda dando vueltas en las paredes.

Las fotos: el caracol, con las anémonas que se aprovechan de una base móvil; así les toca mejor comida. Una lapa. Otras están pegadas a la parte trasera del caracol; este está comiendo algas en el vidrio. Las bolitas amarillentas son caca de lapa.

Y finalmente, una concha vacía con otra anémona (anémona verde con rayas anaranjadas: Diadumene lineata.)

(Y ya es primavera; quiere decir que el caracol estaría más contento (contenta? Yo no sé distinguir, pero ellos sí saben.) si le traigo una compañera. Otra visita a la playa cuando la marea está baja.)

Mañana; dejo el tanque y me voy otra vez al bosque.

Side by side

Here's one of the new pink-tipped anemones, feeding and growing, standing tall.

Anthopleura elegantissima

And, right next to it, one of the Leafy Hornmouth snails:

Ceratostoma foliatum, with the Warty tunicate behind it.

I love the contrasting textures, the rough, craggy shell of the snail, and the creamy greens, pinks, reds, and yellows of the soft tissues.

On the hunt

A Leafy Hornmouth snail searching for food climbed the tank wall to the water surface, skating on his collected bubbles.

Ceratostoma foliatum, and bubbles.

They're out of barnacles. And they're hungry. They're checking every corner, every old shell or rock, even the glass walls. And they're not finding anything.

My bad. I'd better go "barnacle shopping" on the beach asap.

Busy, busy!

More test shots; back to the aquarium and live critters again.

This first photo is as taken; despeckled, resized, and sharpened only. I left the "dust" in place; it's part of the action.

In the upper levels of the tank, like it would be on the intertidal flats, everything is in constant motion. Here, the red algae sways in the water, and a small family of blue anemones glued to a fragile blade waves its tentacles, hoping to catch some of the swimmers that muddy up the current. Behind, bubbles dance; large ones going down, from the pump; small ones heading back up to the surface, carrying goodies collected en route. Released at the top, the goodies float back down; more specks in the water.

This red algae gathers "dust". I pour clean water over it, or take it out and swish it around in fresh water, and it looks beautifully clean. A few minutes back in the tank, and it's covered in these little specks. Some may be sand, some is detritus, leftovers from critter meals or floating fragments of rotting eelgrass, and the rest is made up of small animals, copepods and amphipods eating detritus, and tiny worms eating copepods and amphipods.

And I hadn't even noticed the hermit until I looked at the photo. There's usually one or two hidden somewhere in this mess.

Everything going at once

On the other end of the tank, and up close to the wall, things are more peaceful.

Leafy hornmouth snail, Ceratostoma foliatum, sleeping.

The water is clearer away from the current; I removed only a handful of swimmers and a scratch on the glass. This snail eats barnacles; in between times, he wanders around the walls, then goes to sleep for a day or so.

His shell started out white and pink, but as he grows it gets craggier and darker. He's beginning to show the "leaves" that give him his name; for now, they're just sharp lengthwise ridges.

Setup for these photos: black poster board behind tank, white reflector above and on both sides, spotlight aimed at top reflector, flash ditto. This seems to work on the upper levels, but not down on the sand. More experimentation needed.

Welcoming committee

For New Year's Day, I posted a photo of a brand new, freshly hatched, pinhead-sized Leafy Hornmouth snail, just starting out on his adventure. This is the backstory.

It started with the small kelp holdfast I brought back from the beach in November. It came with its own cargo of crabs and worms and starfish, but there was a small blank space on the inner side of the clamshell; here, the pair of big snails* in my tank chose to anchor their latest batch of egg cases.

The inner side of the clamshell, as it is today. Much-nibbled-on kelp "roots", and the egg cases at the bottom.

The first of the baby snails started to emerge from the cases a couple of weeks ago. I was on hand to photograph the "birth". So were some other observers, with more ominous intentions.

Three open egg cases. The siphon tip of the latest baby peeks out the exit hole of one.

Several snails hatching at once, at the beginning of the escape. Several egg cases still have their plug in the escape hatch. (Top two on the left, for example.) But look carefully at the background!

Waiting for dinner to be served. Flatworms are always hungry!

There were two flatworms, both very tiny, as flatworms go, humongous in relation to baby snails. One was green; I'd seen it before, but this purplish one has only showed up for the hatching, and has never been seen before or since.

The smallest of the black-clawed crabs, still living in the holdfast.

Against the back wall of the clamshell, too tiny to see without a lens, I found a colony of green anemones. Looking again later, I saw that one had a snail in its mouth.

Watch the holdfast for a couple of minutes, and somewhere among the roots, a worm will poke out his head. There are a dozen or so living here.

Polychaete in his tunnel made of a glued fold in sea lettuce. Tiny, but those jaws will gape as wide as the belly of the beast.

Out searching for food. The tail never leaves the burrow, but he can stretch the full width and height of the holdfast colony.

The brittle stars seem to have disappeared, which would be a relief to the snail parents, if they were of the type to fuss over their offspring. The other two stars have been deported to the shore where they came from, for crimes against snaility. (They were eating the tank cleanup crew; they would have had these babies for appetizers.)

Mortality rates are high in the intertidal zone, especially for the young. One of those egg cases would have started out with about 50 eggs; less than half would survive to hatch. And of the hatchlings, depending on where they emerge and the predator load, anywhere from 50% to 99% will die within the first few weeks.

Observations in San Juan Islands, Washington show that a newly hatched N. lamellosa (Related to my leafies - me) has a 1-2% chance to reach 3mo of age.  An individual reaching 3mo has a 35% chance to reach 1yr of age.  Older, larger, individuals have a 40-60% chance to survive through subsequent years.  Spight 1975 Oikos 26: 9. (From A Snail's Odyssey)

My baby snails, those that made it past the welcoming committee, hurried out of the holdfast to hide in the sand.

On his way.

Zooming in. Siphon to the left, leading the way. Within a few seconds, he had ballooned off the holdfast root, washed away in the current to a "safer" place.

Even out of the holdfast, there are dangers. Hermit crabs. Even the tiny hermit crabs. Shore crabs. Anemones everywhere. Any of these will relish a tender baby snail hors d'oeuvre. The ballooning snail burrowed down into the sand as quickly as he could.

But there are worms down there.

Three times, I've seen a baby on the glass, high above the sand, out of reach of all but the climbing hermits. Good choice. They may survive.

Infant snail, above the water line, surrounded by his own body bubble. Taken through the glass, against the light, which shines through the yellow button at the tip, and shows the ridges on the shell. The dark spot is the operculum, which closes the shell when the snail is resting.

*The parents were Mike and Tillie, Leafy Hornmouth snails (Ceratostoma foliatum). They have since been returned to their home beach, since my visits to the winter shores weren't providing enough juicy barnacles to keep them fed in the tank.

Brand new!

The year, of course; 2015. How time flies!

So do snails. Case in point: this newly-hatched leafy hornmouth snail, getting ready to leap from his sheltering holdfast.

Moving right along.

A moment later, he had dropped down on a thread of slime and ballooned off in the current. I caught up with him on the far end of the tank, now on the sand and burrowing fast, soon out of sight.

Good luck, little snail! And a Happy New Year to all!

Baby pics!

I've been checking those Leafy Hornmouth egg cases in the aquarium every few hours this week, and finally this afternoon, I saw a dark speck on top. Very tiny; it looked more like a speck of dust, and I left it there. This evening, there were three specks. I fished them out with a paintbrush and looked at them under the microscope, because they were too small to see clearly with only the hand lens.

They are baby snails, still carrying what looks like a bit of yolk, but ready to go out into the wide world.

The egg case is 1 cm. long; the baby snail is about 2.5 mm.

Stretching to turn itself over. I had just returned it to the tank, upside-down.

Two of the babies, out of the tank.

Now, three hours later, another four have emerged, and there are several in the "birth canals", the pointed top ends of the egg cases. More are waiting inside.

The first three have gone on their ways. I don't see them anywhere;it's a big, busy tank, with many hiding places. And many dangers. I hope they have found safe havens.

And meanwhile, Ma and Pa are down on the bottom of the tank, pigging out on a rock full of barnacles that I brought them this Monday.

Babies, babies!

The snails are hatching! Three are out and exploring their new home, already!

I'll have photos asap.

Couldn't wait to crow!

Reconsidering

A couple of years ago, faced with snail egg capsules and an infant snail found with them, I tentatively identified them (with help from commenters here) as one of the rock snails, aka murex snails or Muricidae. I thought they were probably Trophonopsis orpheus, or another of the trophons. These prey on barnacles or mussels and other bivalves, and seemed to match some barnacle-eaters I'd had previously in the aquarium.

The hatchling, only a few millimetres long.

There were problems with the id; some references called it a subtidal snail, living at depths up to 180 feet. But I had found these in the upper intertidal zone. In Marine Life of the Pacific Northwest, it was the only rock snail that matched the snails I found, but again, it was supposed to be subtidal.

So every time I find another of these, or mention them, I spend some time reviewing the websites and books, looking for a closer match, a snail that fits everything I'm seeing in my tank.

And now, having the egg cases at hand, and confirming that these snails do, in fact, lay these eggs, I think I've been mistaken; that they are no trophons, after all.

Look at these egg cases. (Copyrighted, so you'll have to go there to see them. Here's the page; scroll to the second species.)

Now look at these, from my tank.

Tillie's eggs. A good match.

These are from the Leafy Hornmouth, Ceratostoma foliatum. This is another Muricid (rock or murex snail) that lives in the intertidal zone, but almost all the photos I find are of the full-grown adults; in these, the ribs are prominent, "leafy". The younger ones are like those in my tank.

This is fairly common to find intertidally.  The juveniles exhibit crosshatch sculpturing.  The axial ribs grow to large flares as it matures.  The adults may be plain white to purplish and may be striped.  At the base of the aperture there is a projecting tooth.  It lays a distinctive egg case. (From PNWSC.)

The Wallawalla.edu page adds more details: the siphonal tube of the Leafy Hornmouth is closed along its length, opening again at the tip. And the foot is a mottled cream colour.

(The siphonal canal of Trophonopsis is open.)

This is the youngest one in my tank, still quite small. The siphonal canal is completely fused along its length. The tooth is only visible from this angle as a slightly whiter spot. The shell is white with purplish stripes.

Here's the tooth, looking from the side.

Tillie, laying her eggs. The siphonal canal is closed, the tooth is near the entrance to the canal, and the flesh is a mottled creamy colour.

Down at the beach this afternoon, just below the high tide line, I was turning over rocks, looking at flatworms and a variety of eggs and egg cases. On one stone, I found several clumps of freshly-laid egg cases to match the ones at home. And there were the snails; some laying eggs, some eating barnacles. I turned each one over. Every one had the closed siphonal canal and the tooth.

Snail on rock, stony section of upper intertidal zone, Boundary Bay.

One snail in my tank looks like these, (but cleaner) but is much smaller. And its siphonal canal is open. It has no tooth. It's the oddball. Or it's too young to have developed yet. We'll see.

But. There's always a but.

On the Wallawalla.edu page, I see this:

Depth Range:  Low intertidal zone and subtidal to 60 m.
Habitat:  Found on rocky faces near barnacles and bivalves.  Avoids sand and mud. Most common in areas of strong surf ...

So I'm still not totally convinced; maybe other snails have the same egg cases, the same tooth, and the closed canal. I want to see if Mike and Tillie and their companion develop those big leafy wings as they grow larger. I'll keep on studying the reference sites and books until then.

What do you think?