A really odd relationship under the sea
Pylopaguropsis mollymullerae is a reclusive new hermit crab species discovered sharing caves with a multiple moray eel species. Scientists are still unsure if these hermit crabs serve as cleaners for eels or may be simply commensal den dwellers where the hermit benefits from the protection and food scraps from the moray eel but the eel receives no benefit. Or perhaps the service the hermit crabs provide is tidying up the dens (AKA cleaner crew) for their menacing roommates. In any case, it's an odd harmonious cohabitation.
The new hermit crab species is described in ZooKeys.
In situ photographs of Pylopaguropsis mollymullerae sp. n. and its habitat at Bonaire diving site “Something Special”. A holotype male 2.4 mm, Bonaire (USNM 1291987) B paratype male 1.8 mm, Bonaire (USNM 1291989) C three individuals of P. mollymullerae sp. n. (foreground, not collected) in den with “broad banded moray” Channomuraena vittata D coral ledge habitat, with arrow indicating entrance to crevice where five specimens of P. mollymullerae sp. n. were collected E individual of P. mollymullerae sp. n. (expanded and enhanced in oval inset, not collected) on body surface of “broad banded moray” C. vittata, with frontal portion of brachyuran Achelous sebae visible on lower right.