The furrowed clusterwink Planaxis sulcatus, is a marine snail found on rocky shores in the intertidal zone. They are very common throughout rocky shores in Mauritius. These snails have conical dark greenish-brown shells speckled with white spots. The species can grow up to 35 mm as adults, with females being generally larger than the males. It is distinguishable from the purple coloration of its inner lip which lines its aperture.
The presence of Planaxis sulcatus is wide throughout the Indo-Pacific region. These clusterwinks inhabit the upper and middle parts of the intertidal zone on rocky shores. They are a gregarious species and can be found congregating on rocks during low tides. They are herbivorous and graze on microalgae growing on the rocks, particularly during the incoming tides. During low tide, they withdraw into their shell behind the operculum, and secret mucus from the lip of the shell to enable them to cling to the substrate. Like many other rocky shore species, they are adapted to withstand long hours under the sun and high salinity. When tides permit, they crawl using long tapering cephalic tentacles.
Planaxis sulcatus species is gonochoristic, which means that males and females are distinct individuals. Fertilization is carried out internally through copulation. Reproductive methods may vary depending on the geographic location in its range. In some locations, the female P. sulcatus carries its embryos in large brood pouches on its body.
Currently, Planaxis sulcatus species has not been evaluated by the IUCN Red List and is not considered threatened. However, they are affected by human activities such as coastal development and pollution.
Most clusterwinks are hosts to trematoda – a type of flatworm.