Oxystele sinensisThe pink-lipped topshell also known as the rosy-base topsnail, is a species of sea snail, a marine gastropod mollusk in the family Trochidae, the top snails.DescriptionThe pink-lipped topshell has monomorphic purplish-black shell with a crimson inner lip. The shell in adults is between 18 mm and 51 mm.DistributionThis marine species occurs from False Bay to South Transkei near the Mbashe River, South Africa.EcologyEspecially small individuals of this species that live in the intertidal zone are predated upon by rock lobsters. Larger individuals largely escape this predator by migrating to deeper waters, where they find a size refuge.