Phylum Echinodermata: Subtidal Sea Stars   

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Sea stars, sea urchins, brittle stars, sea cucumbers, feather stars: spiny-skinned animals with endoskeleton of calcium carbonate blocks. Ecologically important predators, grazers, & scavengers in kelp forests. 6000 living species.

Class Asteroidea
  Order Forcipulatida
Leptasterias Orthasterias koehleri Pisaster brevispinus Pisaster giganteus Pycnopodia Stylasterias
Leptasterias Orthasterias koehleri Pisaster brevispinus Pisaster giganteus Pycnopodia helianthoides Stylasterias forreri
  Order Valvatida Order Spinulosida
Dermasterias imbricata Mediaster aequalis Patiria miniata Poraniopsis inflata Henricia spp.
Dermasterias imbricata Mediaster
aequalis
Patiria miniata Poraniopsis inflata Henricia leviuscula
  Order Paxillosida Order Velatida
Astropecten verrilli
Luidia foliolata

Solaster dawsoni
Astropecten verrilli Luidia
foliolata

Solaster
dawsoni
Pteraster tessellatus

  














Pisaster giganteus
Pisaster giganteus  (Stimpson, 1857)
Phylum Echinodermata, Class Asteroidea, Order Forcipulatida, Family Asteriidae

Arm radius to 30 cm (usually much less in Monterey kelp forests), tan with conspicuous white, pink, or purple spines encircled by blue ring around base. 

Very abundant. On rocks, occasionally sand. Most common predatory sea star in Monterey region. Generalist diet includes barnacles, vermetids, turban snails, & many other sessile species.

Geogr. Range: British Columbia to Baja
Synonyms:
Similar species: Pisaster brevispinus is pink with much smaller white spines. Stylasterias is gray-brown, lacks blue rings around spines & is much less common.

Image: Lagenicella (top rt., top left), Corynactis (across top), Celleporella sp. (left of cntr).

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Pisaster brevispinus Pisaster brevispinus  (Stimpson, 1857)
Phylum Echinodermata, Class Asteroidea, Order Forcipulatida, Family Asteriidae

Arm radius to 32 cm, pink with small short white spines. Largest Pisaster species.

Common on sand or mud, occasionally on rock. Preys on a variety of bivalves, burrowing snails such as Callianax, sand dollars (Dendraster).

Geogr. Range: Sitka Alaska to San Diego
Synonyms:
Similar species: this is the only pink sea star in Monterey.


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Orthasterias koehleri Orthasterias koehleri  (de Loriol, 1897)
Phylum Echinodermata, Class Asteroidea, Order Forcipulatida, Family Asteriidae 

Long slender arms; radius to 21 cm. Body red with irregular orange-yellow bands; long spines surrounded by ruffled rings of pedicellaria at base.

Common, on rocks and sandy bottoms. Diet includes gastropods, chitons, barnacles and tunicates. Also can dig up bivalves from sandy areas.

Geogr. Range: Alaska to southern California
Synonyms:
Similar species: bright red and orange color is diagnostic.


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Stylasterias forreri Stylasterias forreri  (de Loriol, 1884)
Phylum Echinodermata, Class Asteroidea, Order Forcipulatida, Family Asteriidae 

Slender arms with radius to 20 cm; long prominent spines and large pedicellaria; brown to gray-brown. 

Infrequent in Monterey, on rocks & occasionally sand. Preys on variety of invertebrates; can also capture small benthic fishes such as sculpins with its large pedicellaria.

Geogr. Range: SE Alaska to San Diego
Synonyms: Asterias forreri
Similar species: Pisaster giganteus is much more common, with somewhat stouter arms and has blue rings around its large spines.

Image: Didemnum carnulentum (lower left cntr.)

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Leptasterias Leptasterias aequalis (Stimpson, 1862)
Phylum Echinodermata, Class Asteroidea, Order Forcipulatida, Family Asteriidae

Six armed sea star; arm radius to 4 cm. 

Common but inconspicuous in intertidal & shallow subtidal sites. Generalist predator, feeds on small snails, small mussels & barnacles, sea cucumbers. Females brood eggs to juvenile stage under oral disc and do not feed during incubation. 

Geogr. Range: Puget Sound to southern California
Synonyms: previously 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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Pycnopodia helianthoides Pycnopodia helianthoides  (Brandt, 1835)
Phylum Echinodermata, Class Asteroidea, Order Forcipulatida, Family Pycnopodiidae

Sunflower sea star, up to 24 arms with radius 40-60 cm; bluish-purple with reddish-orange highlights. Body much softer & flexible than other sea stars. Largest, most active sea star on Pacific coast.

Common on rocks, sand or mud. Generalist predator & scavenger. Many motile invertebrates have well-developed escape responses to Pycnopodia.

Geogr. Range: Alaska to San Diego (uncommon south of Monterey)
Synonyms:
Similar species: color, size, and body texture of Pycnopodia are distinctive.  Solaster dawsoni is rare in Monterey, has 12-13 arms, lacks obvious spines or pedicellaria on aboral surface. 


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Patiria miniata Patiria miniata  (Brandt, 1835)
Phylum Echinodermata, Class Asteroidea, Order Valvatida, Family Asterinidae

Bat star with short broadly triangular arms, radius to 10 cm. Aboral surface smooth, lacking large spines or pedicellaria; extremely varied in color (red, orange, mottled buff, blue). Individuals with 6 or 7 arms not uncommon.

Ubiquitous; most abundant sea star in Monterey region; on rock, sand, mud. Omnivorous detritivore and scavenger.

Geogr. Range: Alaska to Baja
Synonyms: Asterina miniata
Similar species: Mediaster aequalis has more slender arms and distinct marginal plates around edges of arms.


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Mediaster aequalis Mediaster aequalis  Stimpson, 1857
Phylum Echinodermata, Class Asteroidea, Order Valvatida, Family Goniasteridae  

Arm radius to 10 cm; bright red-orange with triangular arms edged with conspicuous marginal plates.

Moderately common, on rocks and occasionally sand. Preys on sponges, bryozoans, sea pens; also scavenges.

Geogr. Range: Alaska to Baja
Synonyms:
Similar species: Patiria miniata has broader arms that lack marginal plates.

Image: Lagenicella (left of star), Paracyathus (top cntr., bottom rt), Balanophyllia (upper rt.), red sponge Clathria prolifera? (lower rt of cntr.)

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Dermasterias imbricata Dermasterias imbricata  (Grube, 1857)
Phylum Echinodermata, Class Asteroidea, Order Valvatida, Family Poraniidae

Leather star; arm radius to 12 cm; aboral surface smooth & slick, lacking spines or pedicellaria. Gray-green, bluish or tan with patches of red or orange. Strong distinctive garlic or sulfurous odor.

Common, on rocky substrate. Feeds primarily on cnidarians such as Epiactis prolifera and Corynactis. Diet also includes a variety of motile invertebrates (sea cucumbers, sea urchins).

Geogr. Range: Alaska to Baja
Synonyms:
Similar species: smooth texture & color pattern are distinctive.


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Poraniopsis inflata Poraniopsis inflata  (Fisher, 1906)
Phylum Echinodermata, Class Asteroidea, Order Valvatida, Family Poraniidae

Short inflated arms; radius to 8 cm; aboral surface with large white-tipped spines, body cream to orange. 

Rare, on rocky substrate only in deep water in Monterey region. 

Geogr. Range: SE Alaska to San Diego
Synonyms:
Similar species: 


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Henricia leviuscula Henricia "leviuscula"  (Stimpson, 1857)
Phylum Echinodermata, Class Asteroidea, Order Spinulosida, Family Echinasteridae

Long slender arms, radius to 8 cm; color usually orange, but varies from tan to dark red or even purple. 

Common, on rocky substrate. Diet includes a variety of sessile invertebrates (bryozoans, tunicates, sponges), but also consumes bacterial films & fine particulate matter.

Geogr. Range: Aleutian Islands to Baja
Synonyms:
Similar species: several subspecies or varieties are recognized; this is probably a complex of several species.


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Astropecten verrilli Astropecten verrilli  de Loriol, 1899
Phylum Echinodermata, Class Asteroidea, Order Paxillosida, Family Astropectinidae

Arm radius to 7 cm, gray to pinkish tan; conspicuous aboral marginal plates that lack spines; tube feet pointed & lack suckers.

Infrequent in Monterey; burrows shallowly in sand. Preys primarily on the snail Callianax biplicata.

Geogr. Range: central California to Baja
Synonyms:
Similar species: Astropecten armatus occurs only south from San Pedro (southern California) & possesses short spines on its aboral marginal plate.


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Luidia foliolata Luidia foliolata  Grube, 1866
Phylum Echinodermata, Class Asteroidea, Order Paxillosida, Family Luidiidae

Long flexible straplike arms, rectangular in cross section; radius to 20 cm, gray to brown. 

Uncommon in Monterey; on sand or mud. Burrows shallowly, seeking bivalves, ophiuroids, polychaetes, etc as prey.

Geogr. Range: SE Alaska to San Diego
Synonyms:
Similar species: Astropecten verrilli occurs in same habitat, but possesses conspicuous marginal plates on aboral edges of arms.


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Solaster dawsoni Solaster dawsoni  Verrill, 1880
Phylum Echinodermata, Class Asteroidea, Order Velatida, Family Solasteridae

12-13 arms, radius 16 cm; aboral surface smooth lacking large spines or pedicellaria; gray, brown, cream or yellow (sometimes bright red or orange). 

Rare in Monterey; on rocks or sand. Preys primarily on other sea stars (e.g. Mediaster, Pycnopodia, Dermasterias), many of which have well-developed escape responses.

Geogr. Range: Aleutian Islands to Monterey
Synonyms:
Similar species: Pycnopodia helianthoides has more arms, evident aboral spines & pedicellaria & a soft texture. Solaster stimsoni has only 10 arms, is red or orange with distinct gray stripe along each arm (absent south of Salt Point, Sonoma Co.).


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Pteraster tessellatus
Pteraster tessellatus  Ives, 1888
Phylum Echinodermata, Class Asteroidea, Order Velatida, Family Pterasteridae

Inflated arms short and stout; radius to 7 cm; color varies from gray to cream, yellow or tan.  No spines or pedicellaria on aboral surface

Rare in Monterey; on rocky substrate. Secretes copious mucus as a defense mechanism.

Geogr. Range: Bering Sea to Carmel Bay
Synonyms:
Similar species: 


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Page created by J.M. Watanabe
All images copyright James Watanabe unless otherwise indicated
Contact:  watanabe_at_stanford_dot_edu                                                                                                                                   Last  update: 10 October 2009