Tag Archives: hermit crab

Pagurus beringanus: Bering hermit crab–The Race Rocks Taxonomy

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Pagurus beringanus, The Bering hermit crab. photo by Ryan Murphy, 2010

This is a tentative identification of Pagurus Beringanus – the Bering Hermit Crab is an animal that is found from the Bering Sea to Monterrey, California. They are also found at Race Rocks. Commonly found at depths from intertidal to 365 meters.

This Pagurus is identifiable by their pale grey-blue shells (carapaces) mottled with grey, red and yellow spots. Legs are also pale blue with red bands at the joints. Claws are reddish and densely covered with spines. Bering Hermit Crabs all have characteristic green, irridescent eyes
Habitat – rocky, intertidal areas with cold water.
Behavior – Adults are inactive during the day. Starting late afternoon and carrying on through the night they become active and feed. This is because the retinal pigments in the eyes with position of the day and the night, only in response to the ambient light in the water.
Bering Hermit Crabs are scavengers, which makes the fact that they taste good puzzling. They eat dead plant materials and dead animal matter.
They themselves are prey to several types of fish, including pine perch, the California sheephead and the spotted kelpfish.
Females have been recorded with eggs mainly in April and May but some as early as February. During courtship, the male carries the female around for a day or more, knocking their shells together. The actual mating lasts less than a second, and both animals come almost completely out of their shells to perform the act.
References:
Intertidal Invertebrates of California. Morris, Abbot, Haderlie, 1980
Pacific Coast Crabs. Gregory C Jensen, 1995
Between Pacific Tides. Ricketts, Calvin, Hedgpeth, 1997

Classification:
Domain: Eukarya
Kingdom: Animalia
Phylum: Arthropoda
Class: Crustacea
Order: Decapoda
Superfamily: Paguridea
Family: Paguridea
Genus: Pagurus
Species: beringanus
Common Name: Bering Hermit Crab

Other Members of the Phylum Arthropoda at Race Rocks.

taxonomyiconReturn to the Race Rocks Taxonomy
and Image File
pearsonlogo2_f2The Race Rocks taxonomy is a collaborative venture originally started with the Biology and Environmental Systems students of Lester Pearson College UWC. It now also has contributions added by Faculty, Staff, Volunteers and Observers on the remote control webcams.
Carmen Braden (PC yr 29) 2002

 

Elassochirus tenuimanus The Race Rocks Taxonomy

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Domain Eukarya
Kingdom Animalia
Phylum Arthroppoda
Class Malacostraca
Order Decapoda
Family Paguridae
Genus Elassochirus
Species tenuimanus
Common Name: Wide-hand hermit crab

In this video, Elassochirus has been disturbed from eating a limpet (Collisella instabilis). It recovers and returns to eating. Note the colouration of the appendages of the hermit crab. Also note that one arm is much wider than the other. The Collisella which normally has a pale shell, is encrusted with the pink algae Lithothamnion.

General Description:
Named as wide-hand, this species hermit crab has a large and flattened right side of chela, carpus and propodus more than its left side. The right cheliped has a wider carpus than it is long. The walking legs have colours of white, reddish brown and purplish-blue on its merus.

Size:
The exterior length is up to 42 mm (1.6 inches).

Natural History, Habitat and geographical and depth range:
Mud, sand, shell bottoms, and especially rocks. The depth range is intertidal (infrequently) to 388 m (1272 feet). For the geographical range, the hermit crab lives in Bering Sea and Aleutian Islands, from Alaska to Washington, and the northwestern Pacific.
Ovigerous females in Washington usually appear from August to May.  Larvae produce from March to May and Planktonic are in last months of the year.

Behavior
When the animal retreats inside, the right claw is used to block the access to the shell itself. The crab bents this claw beneath the body while walking.

References:
– Pacific Coast Crab and Shrimps, Gregory C. Jensen; Sea Challengers Monterey, California, 1995.

– Marine Invertebrate of the Pacific Northwest, Eugene N. Kozloff; University of Washington Press, Seattle and London, 1996.

http://people.wwc.edu/staff/cowlda/KeyToSpecies/Arthropoda/Crustacea/Malacostraca/Eumalacostraca/
Eucarida/Decapoda/Anomura/Family_Paguridae/Elassochirus_tenuimanus.html

 

Pagurus hirsuitiusculus: hairy hermit crab–The Race Rocks Taxonomy

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This video shows the two species, the Hairy hermit crab Pagurus hirsuitiusculus and the sponge Suberites in a commensal biotic association.

hairy-pagurus

Hairy Hermit Crab: photo by Ryan Murphy

bandedantennae

A distinguishing feature of the hairy hermit crab is te banded antennae shown in this image from the video

The specimens studied were collected at  Race Rocks in November of 2002. They were unique specimens because of their choice of home. Usually hermit crabs use the shells of snails that have died then discard them as they grow larger in place of a bigger shell. However, these Hairy Hermit Crabs had decided to become the hermit crabs of Hermit Crab Sponges.

Hermit Crab Sponges, Suberites.spp are sponges that attach themselves to a mobile animal who has a solid exoskeleton, usually a snail or crab. In the hermit crab’s case, the sponge begins to grow on their adopted home by first thinly encrusting the shells. As the sponge grows, it begins to cover the shell and can surround it completely, sometimes making locomotion difficult for the crab. Once the sponge has buried the shell inside itself, the hermit crab leaves its shell to occupy a chamber in the sponge it had hollowed out.

CLASSIFICATION:
Domain: Eukarya
Kingdom: Animalia
Phylum: Arthropoda
Class: Crustacea
Order: Decapoda
Superfamily: Paguridea
Family: Paguridea
Genus: Pagurus
Species: hirsuitiusculus
Pagurus hirsuitiusculus
Common Name: Hairy Hermit Crab

Other Members of the Phylum Arthropoda at Race Rocks.

taxonomyiconReturn to the Race Rocks Taxonomy
and Image File
pearsonlogo2_f2The Race Rocks taxonomy is a collaborative venture originally started with the Biology and Environmental Systems students of Lester Pearson College UWC. It now also has contributions added by Faculty, Staff, Volunteers and Observers on the remote control webcams.

 

Suberites suberea: Hermit Crab Sponge–The Race Rocks Taxonomy

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Suberites suberea is also known as Suberites ficus .This sponge begins its life by attaching to a mollusc shell. As it grows, it overtakes the shell and eventually dissolves it. A hermit crab (Pagurus sp.) is usually found in the cavity of the sponge, but the sponge is usually quite larger than the crab itself. The sponge is hard and rubbery in texture, and is dark orange in colour. It is Found all around the intertidal and shallow subtidal areas of Race Rocks.

Domain Eukarya
Kingdom Animalia
Phylum Porifera
Class Demospongiae
Order Hadromeridia
Family Suberitidae
Genus Suberites
Species suberea
Common Name: Hermit Crab Sponge

This file is provided as part of a collaborative effort by the students of Lester B. Pearson College Dec. 2002 Jana Morehouse Link to other sponge specimens from Race Rocks Link to the Race Rocks Taxonomy and Image gallery index

This file is provided as part of a collaborative effort by the students, faculty, staff and volunteers  of Lester B. Pearson College Dec. 2002 Jana Morehouse

 

Orange hermit crab

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In this video, the orange hermit crab inhabits the shell of an Oregon triton


The Elassochirus gilli (Benedict 1892), commonly known as the Orange Hermit Crab, is commonly found in the waters around Race Rocks. Hermit crabs are abundant around the world. They have soft rear ends that need the protection of the hard snail shell for survival. Hermit crabs carry their shell homes on their backs and tuck themselves away inside for protection using their strong stomach muscles. Sometimes, hermit crabs experience housing problems. As the crab outgrows one shell, it must find another often running into serious competitions for available homes in the right size range. Once it has found a suitable home it will not look again for some time. In any case, hermit crabs will fight for exclusive rights to empty shells. However, they will never displace a live snail from its home.In the video above, the crab inhabits the shell ot the Oregon triton snail, Fusitriton oregonensis .They have two sets of legs that they extend outside their shell for walking and two pairs of legs tucked away inside that they use to move their body around inside their shell.
The right cheliped surface of the Elassochirus gilli is smooth (without small spines) with its shield equal in length and width. The eyestalk of the crab is stout and its cornea is not inflated. The left hand is oval with a wide fixed finger. However, its greatly expanded and flattened right claw is a distinguishing feature. The walking legs of the crab are compressed and yet another distinguishing feature of the species is its bright blue upper leg. The Elassochirus gilli is usually rather uniformly orange to red.

The size of the male crab, is on average, about 20.4m in length. In this secies, the males are without paired pleopods and the females are without paired gonoppores.

The Elassochirus gilli prefers bedrock in areas of fast moving current. As such, its primary habitat is in rocky areas.
Domain Eukarya
Kingdom Animalia
Phylum Arthropoda
Class Crustacea
Order Decapoda
Infraorder Anomura
Superfamily Paguroidea
Family Paguridea
Genus Elassochirus
Species gilli
COMMON NAME: Orange Hermit Crab

WEBSITES AND REFERENCES ON ELASSOCHIRUS GILLI

http://www.oceanlink.island.net/oinfo/biodiversity/hermitcrab.html

Kozloff, Eugene N. Seashore Life of the Northern Pacific Coast, University of Washington Press (1996), p.410

Hart, Josephine F. Crabs and their Relatives of British Columbia, British Columbia Provincial Museum, Victoria (1982), p.124

pearsonlogo2_f2The Race Rocks taxonomy is a collaborative venture originally started with the Biology and Environmental Systems students of Lester Pearson College UWC. It now also has contributions added by Faculty, Staff, Volunteers and Observers on the remote control webcams. Dec 2001- N’kiru Okagbue