Wavy Turban

megastraea undosa

The Wavy Turban (Megastraea undosa) is a large, marine gastropod mollusk known for its heavy, beautifully sculpted shell. Found gliding slowly along the rocky subtidal reefs and kelp forests of the eastern Pacific, this snail plays a key role in its ecosystem by grazing on giant kelp and other algae. Its scientific name, undosa, translates to 'wavy,' highlighting the distinctive undulating ridges that decorate its robust shell. Want to find and snap Wavy Turban yourself? Get the Snappit app.

Habitat: Found in shallow rocky reefs and kelp forests along the coast, spanning from the low intertidal zone down to depths of about 30 meters.

Appearance

The Wavy Turban features a thick, conical shell that typically grows between 8 and 15 centimeters in diameter. Its exterior is marked by prominent, wavy spiral cords and is naturally a dull reddish-brown to gray, though it is frequently overgrown with pink coralline algae, bryozoans, and other marine life. A key identifier is its heavy, white calcareous operculum (trapdoor) which has several distinct, curved ridges. When flipped over, the shell's interior reveals a beautiful, iridescent pearly nacre.

KingdomAnimaliaPhylumMolluscaClassGastropodaOrderTrochidaFamilyTurbinidaeGenusMegastraea

Wavy Turban

Interesting facts

Because they host so many epiphytic organisms on their shells, a single Wavy Turban can carry its own miniature ecosystem of bryozoans, sponges, and small anemones.

The beautiful inner nacre (mother-of-pearl) of their shell has been used historically by Native American tribes, like the Chumash, for creating fishhooks, ornaments, and currency.

Their heavy, calcified trapdoor (operculum) is often referred to by beachcombers as a 'cat's eye' and is highly prized for jewelry-making.

Special abilities

Utilizes an exceptionally thick shell paired with a heavy, calcified operculum that acts as a tight-fitting door, sealing the snail safely inside away from predators.

The rough texture of its shell actively encourages the growth of crustose coralline algae and small invertebrates, rendering the snail nearly invisible against rocky reef backgrounds.

Possesses a specialized, file-like ribbon of teeth called a radula, which is strong enough to scrape and shred tough kelp holdfasts and stipes.