These commensal crabs live exclusively on various species of sea cucumbers, where they often sit just inside the mouth or anus and sample bits of food being injested by the holothurian host. They may also wander about on the surface of the host. They come in dark with white spots or light with dark spots, sometimes on the same host.
Some are very cryptic on their sand-covered holothurian hosts.
Peeking out of the mouth of a sea cucumber.
Created 12 September 2021