Euprotomus aurisdianae

Euprotomus aurisdianae, called the Diana conch, is a small to medium-sized marine gastropod in the true conch family, Strombidae. Its shell is thick and solid, with a nearly elliptical outline, a tall pointed spire, and an irregular body whorl decorated with large knobs and distinct, diverging ridges. The flaring outer lip has a characteristic backward extension that resembles a spine, reaching about halfway up the shell’s apex.

Fine ridges, or liration, appear near the front and back ends of the outer lip. The inner lip is smooth with a thin callus. The siphonal canal is strongly curved, and the stromboid notch is deep and easy to see.

Shell color ranges from dull cream to pale gray, marked with irregular darker spots and lines. The ventral callus and inner lip are usually glossy white, while the interior of the aperture is rich orange or pink, fading toward the outer lip margin. This species can reach a maximum shell length of 90 mm, though it more commonly grows to 70 mm.

The Diana conch lives in the West Pacific, from Japan in the north down to northern Queensland, Australia. In the Indian Ocean, it is replaced by the similar species Euprotomus aurora, which was long confused with E. aurisdianae.

Its habitat includes intertidal and shallow subtidal zones, such as coral sand, grassy sand flats, and dead coral in shallow coral reef areas, down to about 10 meters deep. It is a herbivore. Where abundant, this snail is collected for food. Its shell is also used in shellcraft and sold in local markets, especially in the central and northern Philippines.