Dermasterias imbricata (Grube, 1857)

Common name(s): Leather star
Synonyms:
Phylum Echinodermata
 Class Asteroidea
  Order Valvatida
   Suborder Granulosina
    Family Asteropseidae
Dermasterias imbricata at Beach #4, WA
(Photo by: Dave Cowles, July 2005)
Description:  This star has a broad central disk and 5 short rays which taper broadly to the central disk.  The rays are not bordered by marginal plates.  The entire aboral surface is smooth and slippery, reddish brown with blue-gray patches or reticulations, and without spines.  The thickness is about 1/3 the diameter, the madreporite can be seen.  Smells distinctive--almost like garlic or burned gunpowder.  Arm radius to 15 cm.

How to Distinguish from Similar Species:  Pteraster tesselatus does not have a visible madreporite and secretes copious quantities of slime.  Asterina miniata and Mediaster aequalis have clearly visible interlocking ossicles on the aboral surface.

Geographical Range:  Sitka, Alaska to Sacramento Reef, Baja California, Mexico; more common in the northern half of its range

Depth Range:  Intertidal to 90 m

Habitat:  Mostly on rocks, can also be found on sand or mud.  Seems to prefer at least partially sheltered areas.

Biology/Natural History:  Prey include diatoms, sponges, bryozoans, sea pens, anemones, sea cucumbers, sea urchins, and chitons, ascidians, and fish eggs.  Anemones are said to be one of its major prey items.  It usually swallows its prey whole and digests them internally.  The swimming anemone Stomphia sp has a strong escape response from this species; as does the purple urchin Strongylocentrotus purpuratus.  Stomphia swims away, while S. purpuratus pulls in its tube feet, depresses its spines, and extends its pedicellariae; then races away.  The scaleworm Arctonoe vittata is a common commensal, and the worm and the seastar are mutually attracted to one another.  A parasitic barnacle Dendrogaster sp may be found inside.  In Wasington, spawning is from April to August.  Females release yellow eggs which are fertilized in the water.


 
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References:

Dichotomous Keys:
  Flora and Fairbanks, 1966
  Kozloff 1987, 1996
  Smith and Carlton, 1975

General References:
  Brusca and Brusca, 1978
  Carefoot, 1977
  Gotshall, 1994
  Harbo, 1999
  Hinton, 1987
  Johnson and Snook, 1955
  Kozloff, 1993
  McConnaughey and McConnaughey, 1985
  Morris et al., 1980
  Niesen, 1994
  Niesen, 1997
  O'Clair and O'Clair, 1998
  Ricketts et al., 1985
  Sept, 1999

Scientific Articles:
 

Web sites:
 


General Notes and Observations:  Locations, abundances, unusual behaviors:
 

4 rays

This individual, seen in a tidepool at Cape Flattery, has only 4 rays.


Authors and Editors of Page:
Dave Cowles (2005):  Created original page