Pagurus pollicaris
Say, 1817
flat-clawed hermit crab, flatclaw hermit crab, gray hermit crab, shield hermit crab, thumb-clawed hermit crab, broad-clawed hermit crab, warty hermit crab
Pagurus pollicaris is a marine hermit crab found along the Atlantic coast of North America. It inhabits empty gastropod shells, particularly those of shark and whelks, and reaches approximately 31 mm in length. The is distinguished by its broad, flat that can lock together to form an when the crab withdraws into its shell.
Pronunciation
How to pronounce Pagurus pollicaris: //pəˈɡjʊərəs ˌpɒlɪˈkɛərɪs//
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Identification
The broad, flat that can lock together to function as an are diagnostic. The uneven claw size and pale off- coloration help distinguish it from similar hermit crabs in the Pagurus.
Images
Appearance
Pale off- coloration. length up to 31 mm, width up to 25 mm. Possesses unevenly sized, broad, flat that can interlock to seal the shell opening when the animal retracts.
Habitat
Marine intertidal and shallow subtidal zones. Occupies empty gastropod shells, primarily those of shark (Neverita spp.) and whelks (Buccinidae), which provide shelter for the soft, asymmetrical .
Distribution
Atlantic coast of North America from New Brunswick, Canada south to the Gulf of Mexico.
Diet
, consuming matter, , and occasionally other hermit crabs.
Host Associations
- Neverita - Shark shells used as shelter
- Buccinidae - Whelk shells used as shelter
- Stylochus ellipticus - Zebra flatworm commonly shares the shell
Behavior
Withdraws deeply into shell and seals opening with interlocked when threatened. Shares shells with the commensal flatworm Stylochus ellipticus.
Ecological Role
Scavenger and . Serves as for fish. Provides for commensal flatworms.
Similar Taxa
- Pagurus bernhardusCommon hermit crab in eastern Atlantic; distinguished by P. pollicaris's broader, flatter with -forming capability
- Pagurus hirsutiusculusHairy hermit crab with appendages; P. pollicaris lacks dense hairiness and has distinctive flat
More Details
Shell commensalism
The zebra flatworm Stylochus ellipticus is frequently found sharing shells with P. pollicaris, representing a commensal relationship where the flatworm benefits without apparent cost or benefit to the crab.