Eupentacta quinquesemita (Selenka, 1867) 

Common names:  Stiff-footed sea cucumber, white sea cucumber 
Synonyms:  None
Phylum Echinodermata
 Class Holothuroidea
  Order Dendrochirotida
   Family Sclerodactylidae
Found in Rosario Bay, WA.  Side view.  Animal is approx. 8cm in length.
Photo by: Kelly Williams, June 2002
Description:  Cylindrical, white or cream-colored cucumber about 4-10 cm long.  The tube feet are restricted to ambulacra, forming a double row in each radius, strongly supported by skeletal elements and thus relatively rigid and nonretractile.  The animal has ten branched, yellow oral tentacles: eight longer and two shorter ventral ones.  Skin ossicles include abundant large, porous, oval-shaped ossicles plus smaller, delicate, basket-shaped ossicles.

How to Distinguish from Similar Species:  Looks almost identical to E. pseudoquinquesemita.  The subtle differences are that E. pseudoquinquesemita has finer and more abundant tube feet with a broad space between the ambulacra.  Its body is also softer (less rigid support from calcareous elements).  E. pseudoquinquesemita has the large, oval ossicles in the skin but lacks the smaller, basket-shaped ossicles found in E. quinquesemita.  E. quinquesemita is more abundant in British Columbia (and south?) while E. pseudoquinquesemita is more abundant in Alaska.  If the cucumber is buried and only the white oral tentacles are exposed, it could be confused with Cucumaria pallida.  However, C. pallida has 10 oral tentacles of approximately equal length while E. quinquesemita has 8 long and 2 short.

Geographical Range:  Sitka, Alaska to Baja California; Japan

Depth Range:  Low intertidal to 55 m

Habitat:  Under and between rocks and in crevices.  Often found in areas of strong current.

Biology/Natural History:  E. quinquesemita is eaten by the sea stars Solaster stimpsoni, Pycnopodia helianthoides, and Dermasterias imbricata, and juvenile Eupentacta are a staple food for Leptasterias hexactis.  Adults rarely expose their tentacles during daylight hours.  Typically have bits of shell and other materials attached here and there to the tube feet.  Spawning occurs in the spring (March to May).  Development is indirect.  Eggs, embryos, and larvae are greenish in color.  The body wall is poisonous to at least some fish.  This species eviscerates seasonally in the fall.  Thyonicola americana is a shell-less snail that parasitizes the gut.


 
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References:
Dichotomous Keys:
  Kozloff, 1987
  Carlton, 2007

General References:
  Harbo, 2011
  Lamb and Hanby, 2005
  Lambert, 1997
  Morris, Abbott, and Haderlie, 1982.
  O'Clair and O'Clair, 1998
  Ricketts et al., 1985
  Sept, 1999.

Scientific Articles:
Byrne, M., 1998.  Ultrastructure of autotomy and catch connective tissue regions of the integument of Eupentacta quinquesemita (Holothuroidea).  p 447 in Rich Mooi and Malcolm Telford (eds), Echinderms:  San Francisco.  Proceedings of the ninth international Echinoderm Conference San Francisco, California, USA 5- August 1996.  A.A. Balkema


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


Authors and Editors of Page:
Kelly Williams (2002):  Created original page
Edited by Hans Helmstetler 12-2002; Dave Cowles 2013