Tetraclita rubescens , the pink volcano barnacle, is a species of sessile barnacle in the family Tetraclitidae. T. rubescens is a sessile barnacle with a diameter usually to 30 mm, rarely to 50 mm. Exoskeletal wall consists of four plates with no basal plate (all other local acorn barnacles have 6 plates). The shells of adults are pink to reddish and appear thatched, while the shells of (uneroded) juveniles are white (Morris et al. 1980).