Pagurus kennerlyi (Stimpson, 1864)

Common name(s): Bluespine hermit

Synonyms:  Eupagurus kennerlyi
Phylum Arthropoda
 Subphylum Crustacea
  Class Malacostraca
   Subclass Eumalacostraca
    Superorder Eucarida
     Order Decapoda
      Suborder Pleocyemata
       Infraorder Anomura
        Superfamily Paguroidea
         Family Paguridae
Pagurus kennerlyi from 100 m depth, San Juan Channel.  Animal is encased in a sponge (Suberites sp?).
(Photo by: Dave Cowles, July 2000)
Description:  Pagurus kennerlyi is a deep-living hermit crab which has a carpus of its right cheliped longer than wide and not flattened; the carpus of the left cheliped is twice as long as wide; dactyls of legs 2 & 3 are not twisted (photo); dorsal surface of palm (propodus) of left chela does not have a prominent ridge or crest near the midline (photo); the ventral surface of the merus of the right cheliped has no prominent tubercles (photo); and the distal portion of the merus of the chelipeds has a white band (photo).  The chelae are densely covered with long spines that are pale blue to white (photo) (note they also have setae projecting from them).  Antennae are banded.  Walking legs have reddish-brown blotches and the carapace has reddish markings.  Carapace length to 3.5 cm.

How to Distinguish from Similar Species: Other similar species have no white band on the merus of the chelipeds.

Geographical Range: Aleutian Islands, Alaska to Puget Sound

Depth Range: Low intertidal to 274 m

Habitat: Many habitat types, from rocky to muddy

Biology/Natural History: In the San Juan Islands this species is common subtidally on silty sand bottoms near large rocks.  Sometimes uses the hermit sponge Suberites.



 
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References:

Dichotomous Keys:
  Coffin, 1952
  Hart, 1982
  Kozloff 1987, 1996
 

General References:
  Jensen, 1995

Scientific Articles:
 



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


Front view of Pagurus kennerlyi in sponge.  Photo by Dave Cowles, 2000


Here is another individual peering from its sponge shelter.  The sponge is 2 cm wide.  Photo by Dave Cowles July 2008


This is the same individual as was shown peering out of the sponge above.  Photo by Dave Cowles July 2008
 
 


Pagurus kennerlyi captured at 100 m depth in a San Juan Channel trawl.  The limpet Acmaea mitra is perched on its shell.
 



Only the carapace shield is calcified, and it is about as wide as long.  The eyescales end in a single spine.  Patches of setae occur in many parts of the body.



In this view one can see that the carpus of the right cheliped is about twice as long as wide, and also can see the white band around the distal end of the merus of the cheliped.



The dactyls of legs 2 and 3 are not twisted.
 



The chelae are covered with setae and blue or white tubercles, but there is no prominent ridge on the dorsal surface of the left chela.



The merus of the right cheliped has no prominent tubercles on the ventral side.


Here is a ventral view of another individual, also showing the lack of prominent tubercles on the ventralmerus of the right cheliped.
 
 


As with most hermit crabs, the abdomen is soft and curved.  The male has uropods on the end of the abdomen.


Leg (pereopod) 4 is much smaller than the other legs, and subchelate.



Sometimes this species lives in a sponge, probably Suberites suberea.  I cut this sponge open (the hermit crab is still alive but anesthetized).
Before I cut it open, the sponge was alive and actively pumping water out of the osculum visible on the top of the lower piece.
The hermit had withdrawn completely out of sight within the sponge.  The cavity in the sponge was smooth and coiled like a snail, though I could find no trace of a snail shell.
I sliced through the "body whorl" cavity (lower cross-section), then again about 1 cm to the right side the cavity curled (upper cross-section).  The hermit crab was far back
 in the second whorl as shown, anchored even farther in with its uropods.  I was able to remove the hermit crab from its position above only with difficulty.
Photo by Dave Cowles, July 2005


This individual has clumps of white, bristly setae onthe eyestalks and on the antennae, though the individual above did not.
Photo by Dave Cowles, July 2008
 
 
 



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