| Gumboot chiton | |
|---|---|
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Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Polyplacophora |
| Order: | Chitonida |
| Family: | Acanthochitonidae |
| Genus: | Cryptochiton von Middendorff, 1847 |
| Species: | C. stelleri |
| Binomial name | |
| Cryptochiton stelleri (von Middendorff, 1847) | |
| Synonyms[1] | |
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Thegumboot chiton (Cryptochiton stelleri), also known as thegiant western fiery chiton orgiant Pacific chiton, is the largest of thechitons, growing to 36 cm (14 in) and capable of reaching a weight of more than 2 kg (4.4 lb). It is found along the shores of the northernPacific Ocean fromCentral California toAlaska, across theAleutian Islands to theKamchatka Peninsula and south toJapan.[2][3] It inhabits the lowerintertidal andsubtidal zones of rocky coastlines. The gumboot chiton's appearance has led sometidepoolers to refer to it, fondly, as the "wanderingmeatloaf". The name "gumboot chiton" seems to derive from a resemblance to part of a rubberWellington boot or "gum rubber" boot.[4]
Chitons aremolluscs that have eight armored plates (calledvalves) running in a flexible line down their back. Unlike most chitons, the gumboot's valves are completely hidden by its leathery upper skin orgirdle that usually is reddish-brown or brown, but occasionally is orange in color.
Chitons have long arrays of fineteeth that are partially made ofmagnetite, making its teeth hard enough to scrapealgae off rocks.[5] The styli enclosing their teeth contain the mineralsantabarbaraite,[6] making the gumboot the first organism known to use this material.[7]
The Latin nameCryptochiton stelleri meansSteller's hidden chiton. "Steller" is in honor of the eighteenth-century GermanzoologistGeorg 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, atypically being totally internal in this genus of chiton.[8] Many taxonomic names for chitons are based on the appearance of their plates or valves, so it is most likely that the "hidden" portion of the name refers to the valves being completely obscured by the gumboot's girdle.[9]
The gumboot chiton's underside is orange or yellow and consists mostly of a large foot similar to that of other molluscs such as snails or slugs, withgills found in grooves running along the outer edge of the foot.[3] The gumboot chiton is found clinging to rocks, moving slowly in search of its primary diet ofalgae that is scraped off rocks with its rasp-like retractableradula, which are covered with rows ofmagnetite-tipped teeth. It also eats other marine vegetation such assea lettuce andgiant kelp. Anocturnal 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 intide pools or on rocks.[10]
The gumboot may live for more than 40 years. Several other animal species have been observed living within the gumboot's gills; the relationship is thought to becommensal: benefiting from but not harming the chiton. One researcher found that more than a quarter of gumboots hosted anArctonoe vittata, a pale yellowscale worm that can grow up to 10 cm (3.9 in) length.[2] SometimesOpisthopus transversus, a smallcrab, may be found within the gills of the gumboot.[2]
The gumboot chiton's bony armoring plates, called "butterfly shells" due to their shape, sometimes are found washed up on beaches, as may 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 by heavy waves.
It has few natural predators, the most common being thelurid rocksnail,Paciocinebrina lurida—although the small snail's efforts to consume the chiton generally are limited to the outer mantle only. Sometimes it is reported that the lurid rocksnail is the gumboot chiton's only predator,[11] but others list such animals as the sea starPisaster ochraceus,[12] someoctopus species,[12] and thesea otter as predators upon the gumboot.[13]
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Its flesh is edible and has been used as food byNative Americans, as well as byRussian settlers inSoutheast Alaska.[10] However, it generally is not considered palatable, having a texture described as extremely tough and rubbery.
The writers ofBetween Pacific Tides detailed their culinary assessment 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."[10]
Media related toCryptochiton stelleri at Wikimedia Commons