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

Hairy Hermit Crab: photo by Ryan Murphy

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.

Return to the Race Rocks Taxonomy and Image File

The 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.