An embarrasment of chitons

My guide book lists 30 species of chitons; of these, 24 can be found in the intertidal zone. Most are under an inch long at full growth. Only 4 reach to 4 inches, including the "giant" chiton, which can grow to 14 inches. The largest one I've seen was a bit over 6 inches long.

Giant Pacific chiton, Cryptochiton stelleri

This one, says my book, is the largest chiton in the world. The eight shells, usually visible on most other chitons, are completely hidden by the mantle in this species.On others, the fleshy mantle circles the outer edge.

With these critters being so tiny and often cryptic, I am amazed at the numbers I found near the low tide mark; including yesterday's mossy, I count at least 6 different species, maybe more. Most are smaller than yesterday's; some I only saw examining photos of the tidepools.

Going by the pattern on the shells and the mantle, this may be a woody chiton, Mopalia lignosa.

Unidentified. Although it's on rock, it carries sand stuck to the mantle.

This beautiful critter is really tiny. The purplish mound at the right is a limpet; I'm not sure about the lump in the middle.

And then there were colonies of chitons. I discovered these hiding under a rock where I was looking for starfish.

These are largish chitons; compare with the starfish at upper left.

I count 17 lumps under the mud; some show orange flecks through the mud coat. I couldn't reach them to get one to inspect it more closely.

In a tidepool where I was looking at sea urchins, another miniature chiton showed up. The largest green sea urchins could be up to 3.5 inches across, making this chiton well under an inch long.

Tidepool formed by a circular hole in the sandstone; green sea urchins, branched hydrocorals, encrusting pink stuff, hermit crabs; hairy hermit and ?, limpets and snails, sea lettuce, brown algae, encrusting purple algae, encrusting orange stuff. And that tiny red and pink thing; is it another chiton?

I had tentatively identified this tiny chiton as Gould's baby chiton, but on re-examining it and the guide book, I think it may be the Little Lepidozona, by the size and the pattern of the mantle. This is a subtidal chiton, but this tidepool was at the extreme bottom of the zone, and would always be full of water. But some chitons are extremely variable in colour and pattern, so you never know.

Cropped critters from that tidepool. I wish I had seen that red thing while I was still on the shore.

And another giant chiton, this one all wet and shiny.

Stll washed with the last of the tide.

Tomorrow: an unfortunate sea cucumber.

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Mi libro guía muestra 30 especies de quitones, de los cuales 24 se encuentran en la zona intramareal. La mayoría miden menos de 2 cm. de largo, a lo máximo. Solamente cuatro alcanzan a 10 cm, el más grande siendo el quitón "gigante", que a su crecimiento completo puede medir hasta 35 cm. El más grande que he visto llegó a unos 15 cm.

Primera foto: el quitón Pacífico gigante, Cryptochiton stelleri. Este, dice mi libro guía, es el quitón más grande del mundo. Las ocho placas, que generalmente se ven en los otros quitones, en esta especie están completamente cubiertas por el manto, que en otras especies rodea la parte exterior del animal.

Ya que estas criaturas son tan pequeños, y muchas veces crípticas, me asombra el número que vi cerca del nivel más bajo de la zona intramareal. Incluyendo el quitón musgo que mostré ayer, cuento por lo menos 6 especies distintas, tal vez más. La mayoría son más chicas que el de ayer; algunos no los vi hasta que examiné las fotos de las pozas intramareales.

Segunda foto: por el diseño del manto y las placas, creo que este puede ser el quitón "de madera", Mopalia lignosa.

Tercera foto: este no lo pude identificar. Aunque aparece encima de piedra, trae arena pegada al manto.

Cuarta foto: esta hermosa criatura es pequeñísima. La cosa a la derecha es una lapa.

Y había colonias de quitones. Descubrí estos escondidos bajo una piedra, donde me agaché para mirar estrellas de mar.

Quinta foto: estos quitones son un poco más grandes; compárense con la estrella de mar a la izquierda. Cuento hasta 17 bultos debajo del lodo; en algunos, manchitas anaranjadas se descubren. No me pude acercar más como para alcanzar uno para verlo mejor.

En una poza intramareal donde miraba erizos verdes de mar, se ve un quitón muy pequeño. El erizo verde de mar llega hasta unos 9 cm., haciendo que este quitón medirá menos de 2 cm. de largo.

Sexta foto: la poza intramareal; presentes: erizos de mar, hidrocorales ramificados, masa encrustante color de rosa, otras color de mora y anaranjadas, cangrejos ermitaños; uno es el "peludo", Pagurus hirsutiusculus, lapas y caracoles, algas verde y café. Y ¿qué será esa cosa roja y color de rosa? ¿Será otro quitón?

Había identificado este quitón como el quitón de Gould, pero al examinar mejor la foto y mi libro guía, creo que bien puede ser el Lepidozona chica, por el diseño de las placas y el manto. Aunque este es un quitón de la zona submareal, esta poza estaba al extremo más bajo de la intramareal, y la poza sería siempre completamente llena de agua. Sin embargo, los quitones pueden ser muy variables con respeto al diseño y colores, así que bién puede ser cualquiera de los otros pequeños.

Séptima foto: animales de la foto anterior, para que se vean mejor.

Ocatava foto: otro quitón gigante, este todo mojado y brilloso.

Para mañana: un pepino de mar malafortunado.

Just out of reach

I'm fascinated by the pool under the erratic boulder; I went back again today, and discovered new and amazing things again. More photos to be processed!

So far, I've not found the area dry, so all the photos (and what I saw) are warped under a hand's length of wind-blown water. Some look like abstract paintings:

A cozy home to assorted chitons, various anemones, starfish, encrusting pink algae, barnacles, whelks, and many hermits in smashed shells.

5 or more chitons here. Look for the reddish girdle, with a paler central oval. 

A sample red-girdled chiton, very tiny, found on a rock. 8 pale shell segments and a red-brown girdle.

Another of the black leather chitons. Several species live under this rock.

The view from the access point. The second erratic, where the pool is, is on the far, far right.

Today I walked around the point to a third, slightly smaller erratic, but couldn't quite reach it because the tide was too high, and I was keeping my so-called "waterproof" shoes dry. They can handle an inch of water, but no more, and it's a long walk back with squelchy socks.

Another day, another low tide. At least the weather is finally cooperating.

I brought home another Giant Pacific chiton, very dead; it's soaking now in hydrogen peroxide. If all works out, I'll eventually have photos of the internal shells.

Next: surprising anemones.

Whoppers

On a third visit to the sandstone and erratics beach, I discovered two of the largest chitons I have seen so far, unfortunately dead, left behind by the retreating tide.

Giant Pacific chiton, aka gumboot chiton, Cryptochiton stelleri. This specimen was a bit over 6 inches long. Adults may grow to 14 inches.

Quoting from my Encyclopedia:

"The largest chiton in the world! The giant Pacific chiton's eight shells are completely and cryptically overgrown by girdle."

No other chiton in this area has all 8 plates covered by the mantle, nor grows this large. (From wallawalla.edu)

The mantle was eroded, firm and slightly porous. The shells were only visible as ridges underneath the flesh of the mantle. And from the underside, where the meat had been torn away.

Upside-down chiton. Three shell shapes are exposed.

This chiton has gills along the sides of the foot. The white lines in the grooves here may be bits of the gills. The mantle covers the whole top and laps over the edges, leaving only the foot exposed. Here, it has retracted somewhat as it dried.

These chitons (at least other, less unlucky, members of their families) may live up to 20 years, never straying more than a few metres from home base, at the bottom of the intertidal zone and a bit further out to sea.

Google image of the beach. Access is from a driveway-length road, Shell Road.

Shell Road Beach location