Pagurus samuelis (Stimpson, 1857)

Common name(s): Blueband hermit crab

Synonyms:  Eupagurus samuelis
Phylum Arthropoda
 Subphylum Crustacea
 Class Malacostraca
   Subclass Eumalacostraca
    Superorder Eucarida
     Order Decapoda
      Suborder Pleocyemata
       Infraorder Anomura
        Superfamily Paguroidea
         Family Paguridae
Pagurus samuelis in a Tegula funebralis shell.  At Little Corona del Mar, CA
(Photo by: Dave Cowles, March 2005)
Description:  This intertidal hermit crab has a carpus of the right cheliped longer than wide, the dactyls of the 2nd and 3rd legs are straight and have a bright blue band, the dorsal surface of the left chela has no prominent ridge or crest near the midline, the ventral surface of the merus of the right cheliped has 2 prominent tubercles, and the ventrolateral surface of the propodus and dactyl of leg 3 has 1 or more irregular rows of small spines or tubercles, the chelae have tubercles or granules, the dorsal surface of the carpus of the left cheliped has 2 rows of short spines, rostrum is acute (has a sharp median frontal tooth).  The carapace and legs are hairy with setae.  The antennae are a strong reddish color with no banding.  The dactyls of juveniles are banded white instead of blue.  The tip of the dactyl on the left chela may be red.  Carapace length to 19 mm, total length to about 4 cm.

How to Distinguish from Similar Species: The blue dactyls on the 2nd and 3rd legs, and the red unbanded antennae are distinctive.  Of similar species, P. granosimanus has olive-green legs with small blue dots.  P. beringanus is mostly subtidal and has a red band at the articulation of the propodus and dactyl.

Geographical Range: Alaska to Punta Eugenia, Baja California.

Depth Range: High intertidal to subtidal

Habitat: Rocky intertidal on the outer coast.  Not often found in inland seas.

Biology/Natural History: One of the most common intertidal hermit crabs on the outer coast, especially in southern and central California.  Reproduces in June and July in northern waters.  This species seems to have a strong preference for Tegula funebralis shells, which they will steal from one another.  Do not seem to kill the Tegula to get their shells.  Active especially in the evening and at night.  Adults eat algae, especially large brown algae and scavenge dead animals.  Predators include the pile perch, sheephead, and spotted kelpfish.  During courtship, male grasps female's shell and may carry her around for a day or longer, occasionally knocking his shell repeatedly against hers.  Mating is brief (only a few seconds; both animals must nearly leave their shells to mate).

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Dichotomous Keys:
  Allen, 1976
  Flora and Fairbanks, 1966
  Hart, 1982
  Kozloff 1987, 1996
  Smith and Carlton, 1975
  Wicksten, 2009

General References:
  Jensen, 1995
  Kozloff, 1993
  Morris et al., 1980
  Ricketts et al., 1985

Scientific Articles:

Billock, W. L. and Dunbar, S. G. 2008. Influence of motivation on behavior in the hermit crab, Pagurus samuelis. Journal of the Marine Biological Association of the U. K., Published online by Cambridge University Press 19 Sep 2008 doi:10.1017/S0025315408002543: 1 – 5

Shives, J. and Dunbar, S. G. 2010. Behavioral response to burial in the hermit crab, Pagurus samuelis: implications for the fossil record. Journal of Experimental Marine Biology and Ecology. 388: 33- 38


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

P. samuelis is often more willing than other hermit crab species to stick its legs out of the shell and try to escape.
Photo by Dave Cowles, April 1993.  Dana Point, CA

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