Benhamipolynoe cairnsi is known from the south-west Pacific Ocean from depths of about 400–500m[2]
Benhamipolynoe cairnsi has 10 pairs of elytra (fewer than Benhamipolynoe antipathicola) and the preserved specimens studied thus far are not known to be pigmented.[3]
Benhamipolynoe cairnsi has a commensal relationship with the stylasterid coral Conopora adeta.
Benhamipolynoe cairnsi is known from the south-west Pacific Ocean from depths of about 400–500m