Megastraea undosa

Wavy Turban

Family: Turbinidae · Class: Gastropoda · Order: Trochida

The wavy turban (Megastraea undosa) is a large marine gastropod mollusk belonging to the family Turbinidae. This species exhibits the characteristic turbinate shell shape with distinctive wavy spiral ridges that give it its common name. The shell displays a robust, conical form with pronounced nodular sculpturing along the whorls, creating the undulating pattern for which the species is named. Adult shells can reach substantial sizes, with thick walls that provide protection in the rocky intertidal environment. Megastraea undosa occurs along the Pacific coast of North America, with its range extending from central California southward to Baja California, Mexico. In California, the species is documented from the Channel Islands and coastal waters, including areas near marine protected regions such as Skunk Point State Marine Reserve. The species inhabits the rocky intertidal and shallow subtidal zones of the temperate Pacific Ocean. This gastropod occupies rocky intertidal habitats and adjacent subtidal areas, typically found among kelp forests and rocky reef systems. The species prefers areas with hard substrates where it can graze on algae and other organic matter. Wavy turbans are commonly associated with surfgrass beds, eelgrass meadows, and kelp forest ecosystems that provide both food resources and structural habitat. These environments offer the stable rocky surfaces necessary for the species' grazing lifestyle and protection from wave action. As a herbivorous gastropod, Megastraea undosa feeds primarily on algae and other plant material growing on rocky surfaces. The species uses its radula, a rasping feeding organ characteristic of gastropods, to scrape algae from substrates. Reproduction follows typical gastropod patterns, with individuals being either male or female. The species likely produces planktonic larvae that settle and metamorphose in suitable rocky habitat. Movement is limited to crawling along substrates using the muscular foot typical of gastropods. Currently, Megastraea undosa does not appear on federal or California state endangered species lists, suggesting stable population status as of December 2025. However, like many marine invertebrates, the species faces potential threats from habitat degradation, ocean acidification, and climate change effects on coastal ecosystems. Marine protected areas such as Skunk Point State Marine Reserve may provide important refugia for populations within kelp forest and rocky intertidal communities. The species benefits from protection of kelp forest ecosystems and maintenance of water quality in coastal environments. Continued monitoring of population status and habitat conditions remains important for long-term conservation of this and other rocky intertidal species along the California coast.

Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, and more.