Pagurus beringanus (Benedict, 1892)

Common name(s): Bering hermit crab 

Synonyms:  Eupagurus beringanus, Eupagurus newcombei, Pagurus newcombei
Phylum Arthropoda
 Subphylum Crustacea
  Class Malacostraca
   Subclass Eumalacostraca
    Superorder Eucarida
     Order Decapoda
      Suborder Pleocyemata
       Infraorder Anomura
        Family Paguridae
Pagurus beringanus, total length 2 cm, from extreme low intertidal on Sares Head
(Photo by: Dave Cowles, July 2005)
Description:  This hermit crab has a rounded carapace, red bands on legs including a band at the junction of the propodus and dactyl, The right cheliped, which is larger, has two tubercles on the ventral side of the merus, and the carpus is slightly longer than wide, dactyl of legs 2 and 3 not obviously twisted, and the ventrolateral margin of the propodus on left leg 3 has a row of spines.  Color of legs is white, gray, pale greenish brown, or bluish with red bands and red spines.  Carapace up to 2.5 cm long.

How to Distinguish from Similar Species: Pagurus granosimanus has no spines or tubercles on the ventrolateral margin of the propodus of left leg 3, and the legs are olive-green with blue dots.

Geographical Range: Aleutian Islands, AK to Monterey, CA.  Uncommon S of Point Arena.

Depth Range: Extreme low intertidal to 360 m.  Mainly subtidal in California.

Habitat: Rocky areas, especially around large rock formations in partially protected waters.

Biology/Natural History: Tends to use large, heavy shells such as Nucella lamellosa into which it can withdraw completely.  Sometimes found in a sponge.  Predators include the rosylip sculpin Aschelichthys rhodorus.

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Dichotomous Keys:
  Coffin, 1952
  Flora and Fairbanks, 1966
  Hart, 1982
  Kozloff 1987, 1996
  Smith and Carlton, 1975
  Wicksten, 2009

General References:
  Harbo, 1999
  Jensen, 1995
  O'Clair and O'Clair, 1998
  Ricketts et al., 1985
  Sept, 1999

Scientific Articles:

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

Front view.

Here is a view of the animal outside its shell.  Note the large uropods at the end of the abdomen.  Photo by Dave Cowles, July 2005

Legs 4 and 5 are reduced in hermit crabs, and in most of them leg 4 is subchelate, as seen here.
In the picture, leg 1 (the left chela) is partly hidden.  Legs 2 and 3 are long and used for walking.
Legs 4 and 5 are reduced and used for manipulating the shell.
Photo by Dave Cowles, July 2005

The features in the following pictures are useful for identifying this species:

The carapace shield (anterior, calcified part) is about as wide as long.  The rostrum is rounded.  The eyescales have no deep median furrow and their base is not
covered by the carapace.  The carpus of the right cheliped is longer than wide.  The dorsal surface of the left chela has no prominent ridge near the midline.

This is a view of the carpus, propodus, and dactyl of left legs 2 and 3 (+ a portion of the antennal flagellum).  Anterior is downward.
Note the line of spines easily visible on the posteroventral margin of the propodus of leg 3, and the red band at the junction of the propodus and dactyl.

The merus of the right cheliped has two large tubercles on the ventral side, visible here as orange spots.  Anterior is downward in this photo.

Here is another individual of Pagurus beringanus

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