Berthelinia rottnestiBerthelinia rottnesti is a species of a sea snail with a shell comprising two separate hinged pieces or valves. It is a marine gastropod mollusc in the family Juliidae.DistributionThe type locality for this species is Rottnest Island, Southwestern Australia.DescriptionBerthelinia rottnesti is approximately 6 mm.EcologyThis species can be found in algae and seaweed beds.