The gumboot chiton also known as the giant western fiery chiton, is the largest of the chitons, growing to and over. It is found along the shores of the northern Pacific Ocean from Central California to Alaska, across the Aleutian Islands to the Kamchatka Peninsula and south to Japan. It inhabits the lower intertidal and subtidal zones of rocky coastlines. Chitons are molluscs which have eight armored plates running in a flexible line down their back. Unlike most chitons, the gumboot's valves are completely hidden by its leathery upper skin or girdle, which is usually reddish-brown, brown, and occasionally orange in color. The gumboot chiton's appearance has led some tidepoolers to fondly refer to it as the "wandering meatloaf". Chitons have long arrays of fineteeth which are partially made of magnetite, making its teeth hard enough to scrape algae off of rocks.
Names
The name "gumboot chiton" seems to derive from a resemblance to part of a rubber Wellington boot or "gum rubber" boot. The Latin nameCryptochiton stelleri means Steller's hidden chiton. "Steller" is in honor of the 18th-century German zoologistGeorg Wilhelm Steller, who first described many species of the northern Pacific seashore. "Hidden" or "concealed" refers to the fact that the eight shelly plates characteristic of chitons are not visible, being totally internal in this genus of chiton. Many taxonomic names for chitons are based on the appearance of their plates or valves, and so it is most likely that the "hidden" portion of the name refers to the valves being completely obscured by the gumboot's girdle.
Life
The gumboot chiton's underside is orange or yellow and consists mostly of a large foot similar to that of other molluscs like snails or slugs, with gills found in grooves running along the outer edge of the foot. The gumboot chiton is found clinging to rocks, moving slowly in search of its diet of algae, scraped off of rocks with its rasp-like retractable radula, covered with rows of magnetite-tipped teeth. It also eats other marine vegetation such as sea lettuce and giant kelp. A nocturnal creature, the gumboot generally feeds at night and often remains in a hiding place during the day—although on foggy days it may be found exposed in tide pools or on rocks. The gumboot can live for over 40 years. It has few natural predators, the most common being the lurid rocksnail, Ocenebra lurida—although the small snail's efforts to consume the chiton are generally limited to the outer mantle only. It is sometimes reported that the lurid rocksnail is in fact the gumboot chiton's only predator, but others list such animals as the sea star Pisaster ochraceus, some octopus species, and the sea otter. Several other animal species have been observed living within the gumboot's gills; the relationship is thought to be commensal: neither harmful nor helpful to the chiton. One researcher found that more than a quarter of gumboots hosted an Arctonoe vittata, a pale yellow scale worm which can grow up to length. Opisthopus transversus, a small crab, is also sometimes found within the gills.
Its flesh is edible, and has been used as a food source by Native Americans, as well as by Russian settlers in Southeast Alaska. However, it is not generally considered palatable, with a texture described as extremely tough and rubbery. The writers of Between Pacific Tides further detail the culinary drawbacks of the gumboot: "After one experiment the writers decided to reserve the animals for times of famine; one tough, paper-thin steak was all that could be obtained from a large cryptochiton, and it radiated such a penetrating fishy odor that it was discarded before it reached the frying pan." The gumboot chiton's bony armoring plates, called "butterfly shells" due to their shape, can sometimes be found washed up on beaches, as can whole chitons: the gumboot keeps a weaker grip on the rocks that make up its home than most chitons do, and therefore it is not unusual for them to be knocked loose in heavy waves.
