Pustularia margarita is similar in color to Pustularia cicercula, but it has more obvious scattered minute brown specks and a more slender, always completely smooth shell. While some consider this species to be a smooth form of P. cicercula, it has a different habitat preference; it is most common in seaward reef surge channel caves at night and is less common, but still present, nocturnally in caves on lagoon pinnacles. Pustularia cicercula is the opposite: more common on lagoon pinnacles and less common on the seaward reef. If the two were the same species, you would expect the distribution patterns to be similar. Finding both species in both habitats—just in different percentages—would seem to rule out habitat as a cause of shell differences. Specimens are typically seen at depths of 8-20m although it probably extends deeper. The species appears to range widely in the Indo-Pacific.
Updated 3 April 2024