Cryptolithodes sitchensis Brandt, 1853

Common name(s): Umbrella crab, Turtle crab, Sitka crab
Synonyms:
Phylum Arthropoda
 Subphylum Crustacea
  Class Malacostraca
   Subclass Eumalacostraca
    Superorder Eucarida
     Order Decapoda
      Suborder Pleocyemata
       Infraorder Anomura
        Superfamily Paguroidea
         Family Lithodidae
Cryptolithodes sitchensis from 15 m depth, Sares Head
(Photo by: Dave Cowles, 2001)
Description:  This Lithodid crab has a hugely expanded carapace so wide that it completely covers its walking legs unless the legs are stretched out (picture).  The rostrum is wider distally than it is proximally (picture).  The propodus of the chela is smooth (picture).  The margins of the abdominal plates do not have raised margins (picture).  Dorsal color variable--streaked gray like the specimen above, brown, scarlet (some males), or olive.  Underside of carapace is nearly always white.  Small individuals may be white or light brown.  Male carapace to 9 cm wide.

How to Distinguish from Similar Species: Cryptolithodes typicus has a similar body shape but has a rostrum that is widest at the base, the propodus of its chela is rough, and the margins of its abdominal plates have raised margins.

Geographical Range: Torch Bay, Alaska to Point Loma (San Diego), CA

Depth Range: Intertidal to 15 m

Habitat: Rocky shores, usually on outer coast.  Nestles under rocks or in crevices in algae-covered bedrock, low intertidal and subtidal

Biology/Natural History: This species, like Cryptolithodes typicus, is very slow moving.  Feeds on upright coralline algae such as Corallina, Calliarthron, and Bossiella.  Tends to be found at shallower depths than C. typicus is.


 
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References:

Dichotomous Keys:
  Coffin, 1952
  Hart, 1982
  Kozloff 1987, 1996
  Smith and Carlton, 1975
  Wicksten, 2009

General References:
Gotshall and Laurent, 1979
Kozloff, 1993
Morris et al., 1980
O'Clair and O'Clair, 1993
 

Scientific Articles:
 


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


Cryptolithodes sitchensis rostrum is widest at the tip



Cryptolithodes sitchensis underside.  Note that the propodus of the chela is smooth, and that the abdominal plates do not have raised margins.  The underside of the carapace is nearly always white.
Photo by Dave Cowles, July 2001


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