Pagurus beringanus (Benedict,
1892)
Common name(s): Bering hermit
crab
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Synonyms:
Eupagurus beringanus,
Eupagurus newcombei, Pagurus newcombei |
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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.
References:
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
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