Haplopoma sciaphilum is an encrusting bryozoan that forms small patch-like colonies. Colonies are typically composed of 10-25 autozooids, occasionally reaching 50 autozooids. Autozooids are elongate, oval to hexagonal. They are 0.5-0.55 by 0.26-0.29 mm.
Haplopoma sciaphilum is distributed from West Sweden, through Britain to the Mediterranean and Adriatic Seas.
The species is able to colonise stones and is most frequently found on vertical or overhanging rock. It generally occurs in dark situations such as caves and crevices. It has been recorded from 40 m and extends to at least 500 m.