Phylum Echinodermata, Class Asteroidea, Order Forcipulatida, Family Asteriidae
Common sea star; arm radius to 15 cm; stout tapering arms; short white spines in reticulate pattern; color yellow, pale orange, dark brown, or purple.
Abundant, mid- to low intertidal zones & subtidal, exposed outer coast. Important predator on mussels, snails.
Geogr. Range: Alaska to southern CaliforniaSynonyms:
Similar species: subtidal spp.: Pisaster giganteus has blue rings around white or purple spines; P. brevispinus is pink with small white spines.
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Phylum Echinodermata, Cass. Asteroidea, Order Forcipulatida, Family Asteriidae
Six armed sea star; arm radius to 4 cm; mottled green, purple or red with irregular white bands.
Common in pools & under rocks, mid- & low intertidal zones & subtidal; protected outer coast. Generalist predator, feeds on small snails, small mussels & barnacles, sea cucumbers. In winter, females brood eggs to juvenile stage under oral disc and do not feed during incubation.
Geogr. Range: Puget Sound to southern CaliforniaSynonyms: formerly referred to as Leptasterias hexactis, which is probably a northern species.
Similar species: the small 6-armed sea stars of the Pacific coast are a complex of species that are difficult to distinguish in the field.
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Phylum Echinodermata, Class Asteroidea, Order Valvatida, Family Asterinidae
Bat star; short broad triangular arms; color varies from solid orange to red, mottled cream, or blue; individuals with 6 or even 7 arms are fairly common.
Very common, low intertidal zone & subtidal; exposed & protected outer coast. Omnivorous detritivore.
Geogr. Range: Alaska to BajaSynonyms: Asterina miniata
Similar species:
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Phylum Echinodermata, Class Asteroidea, Order Spinulosida, Family Echinasteridae
Slender arms, radius 2-3 cm (larger subtidally); color varies from uniform red-orange to mottled orange, pink & red.
Common but cryptic, in tidepools & under rocks; lower mid- to low intertidal zones and subtidal. Feeds on sessile invertebrates (bryozoans, tunicates, sponges), as well as bacterial films & fine particulate matter.
Geogr. Range: Aleutian Islands, Alaska to BajaSynonyms:
Similar species: several subspecies or varieties are recognized; this is probably a complex of several species.
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Phylum Echinodermata, Class Ophiuroidea, Order Ophiurida, Family Amphiuridae
Brittle star. Disc to 12 mm diameter w. arms 9-15 times disc diameter; arm segments each with clusters of 3 short spines on each side; gray.
Moderately common but cryptic, under rocks resting on sand or in sea grass roots; mid- to low intertidal zones, protected coast. Can shorten arms into accordion-like squiggles when disturbed; when removed from water, coils arms tightly atop disc; burrows quickly, sinking bodily into sand as podia pass sand grains up quickly to cover aboral surface; deposit feeds or may suspension feed with exposed arm tips.
Geogr. Range: Alaska to San DiegoSynonyms: Diamphiodia occidentalis
Similar species: most other local brittle stars have shorter arms relative to disc diameter.
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Phylum Echinodermata, Class Echinoidea, Subcl. Euechinoidea, Order Echinoida, Family Strongylocentrotidae
Purple sea urchin; test 5 cm diameter (10 cm max), spines short (usually < half diameter of test). Small juveniles often white.
Common in pools, crevices, under rocks; mid- to low intertidal zones & subtidal; exposed & protected outer coast. Herbivorous with a strong preference for giant kelp.
Geogr. Range: Alaska to BajaSynonyms:
Similar species: Strongylocentrotus franciscanus is larger, more red, occurs subtidally.
Image: Leptasterias aequalis (upper left); Chlorostoma funebralis (lower rt.)
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Phylum Echinodermata, Class Holothuroidea, Order Apodida, Family Synaptidae
Wormlike sea cucumber lacking tube feet; white or pale tan, 5-15 cm long; 5 longitudinal muscle bands visible through body wall of relaxed animal with 10 branched oral tentacles surrounding mouth.
Common, under rocks on course sand or shell rubble; mid- to low intertidal zones; protected outer coast; burrowing deposit feeder.
Geogr. Range: northern limit uncertain, but at least central Calif. to BajaSynonyms:
Similar species: 5 spp. of Leptosynapta occur along West Coast.
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Phylum Echinodermata, Class Holothuroidea, Order Dendrochirotida, Family Psolidae
Small sea cucumber, 1.5-2 cm long; dorsal surface bright red-orange or scarlet w. scattered tube feet, ventral side pale and flattened w. clear rows of tube feet; ten unequal tentacles around mouth (8 large, 2 small).
Moderately common but inconspicuous, on rocks or in sand around holdfasts or sea grass; low intertidal zone to subtidal; broods young in shallow depressions on dorsal surface.
Geogr. Range: Monterey Bay to southern CaliforniaSynonyms:
Similar species:
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Phylum Echinodermata, Class Holothuroidea, Order Dendrochirotida, Family Cucumariidae
False tar spot sea cucumber; 1-3 cm; dorsal dk. brown to light brown or yellowish-gray; tube feet in 5 zig-zag rows along body; 8 large & 2 small tentacles around mouth, all darker toward tips.
Locally abundant, but spotty; often amongst mussels or corallines; mid- to low intertidal zones, exposed & protected outer coast; females brood young.
Geogr. Range: British Columbia to Monterey BaySynonyms:
Similar species: Pseudocnus curatus is very similar, but has scattered tube feet & 10 equal tentacles; must examine skin ossicles to confirm.
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Phylum Echinodermata, Class Holothuroidea, Order Dendrochirotida, Family Cucumariidae
Tar spot sea cucumber; 1-3 cm; black; tube feet scattered across dorsum, but in more distinct rows on ventral side; 10 equal-size tentacles around mouth.
Locally abundant, but spotty; low intertidal zone to subtidal, very exposed outer coast; females brood young.
Geogr. Range: probably British Columbia(?) to central CaliforniaSynonyms: Cucumaria curata
Similar species: Cucumaria pseudocurata is very similar, but has dorsal tube feet in rows & 8 large + 2 small tentacles; must examine skin ossicles to confirm.
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