About Pteropurpura festiva (Hinds, 1844)
The shell of Pteropurpura festiva ranges in length between 20 mm and 67 mm. It is an elongately ovate shell with six convex whorls, and each whorl has three low, reflexed varices. These varices are finely frilled on their front surface. Between the varices, a rib bears a large, blunt knob on the shoulder. The wide outer lip is finely dentate, with 5 to 7 teeth on its inner surface. The columella is simple and smooth. The aperture is oval, with a varix that extends to the short, deep, recurved siphonal canal. The shell's ground color ranges from white to light brown, and is crossed by evenly spaced, thin, incised, spiral dark brown lines. Pteropurpura festiva is a formidable predator that feeds on mussels, limpets, barnacles, and other snails. This predatory trait allows it to resist the invasion of the Asian mussel Musculista senhousia in Southern California. This marine species occurs abundantly in the intertidal zone and mud flats, ranging from Southern California, USA where most records come from Santa Barbara, Los Angeles, and San Diego, south to Baja California, Mexico.
