Nucleolaria granulata (Pease, 1862)
Granulate cowry, 33mm

Nucleolaria granulata lives under rocks by day or in ledges and small caves at night, usually between about 4 and 30m. While usually not too uncommon, for several years in the mid 1980s at least it was rarely seen, even in places that presumably saw little or no shell collecting pressure. Like some other species we have observed (e.g., Staphylaea semiplota in Hawaii and Naria beckii in the Marshall Islands), this species apparently undergoes periodic population fluctuations. This species is considered to be endemic to the Hawaiian Islands, although Nucleolaria cassiaui is a very similar species from French Polynesia.

The fully exended mantle bears long papillae, almost making it look like a kind of sea urchin when the mantle completely covers the shell. It also often makes it hard to distinguish against the normal multicolored background at night.

30.5mm specimen below.

Created 25 July 2010
Updated 25 December 2020

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