Hitchhiker Crab ID?

[MykeyJ]

This little guy came in on a cucumber that i just got today. Can anyone help me identify him?

 

[LeslieH]

You should put him back. It's a commensal called Lissocarcinus orbicularis found only on sea cucumbers.

 

[MykeyJ]

Awesome, Thank You.

Am I to understand they have a kind of symbiotic relationship?

I also did not realize there were so many variations of their markings. When I found the crab I thought it was eating the cumber but it sounds like the crab was just cleaning the cumber.

The crab will be put back with the cucumber he came in with so they can continue living together.

 

[LeslieH]

Yes, the crab eats dead skin, mucus, & feces so the cucumber gets cleaned in return for food & a protected place to live. Like many other commensal crustaceans the Lissocarcinus may also help defend its host against predators.