Wrinkled Nut Shell / Ridged Drupe
Phylum: Mollusca, Class: Gastropoda, Order: Neogastropoda, Family: Muricidae, Genus: Drupa, Species: Drupa ricinus · Muricidae (Murex and Rock Shell family) · Gastropod, whole spiral shell
Species
Drupa ricinus
Shell Type
Gastropod, whole spiral shell
Family
Muricidae (Murex and Rock Shell family)
Size
Approximately 1.25 inches in length, which is a standard size for an adult of this species whose normal range is 1 to 1.5 inches.
Color & Pattern
Chalky white base with weathered dark grey to black patches visible along the ridges and nodules. The natural bright colors and distinct dark markings have been heavily sun-bleached and worn due to wave action.
Rarity
Common
Habitat
Shallow intertidal zones, rocky shores, and coral reef flats where they cling tightly to rocks in high-energy surf zones.
Geographic Range
Indo-Pacific region, spanning from East Africa and the Red Sea through the Indian Ocean to Polynesia, Hawaii, and the tropical Pacific.
Description
A robust, heavy rock shell featuring distinct spiral ridges, prominent knobs, and a heavily toothed outer lip. The aperture is narrow and characteristic of carnivorous rock snails adapted to pounding surf.
Key Features
Sturdy spiral construction, rows of blunt knobs or tubercles along the body whorl, and a constricted aperture with strong denticles on the inner edge of the outer lip.
Collector Value
Low to moderate collector value. Beach-worn specimens like this are common finds and hold little monetary value, though they are popular starter pieces for casual beachcombers.
Condition Notes
Fair condition. The specimen is a beach-worn, sun-bleached whole shell with structural integrity largely intact, but missing its original sharp coloration and glossy surface finish.
Interesting Facts
Members of the genus Drupa are active marine predators that feed on other snails and barnacles by boring holes in their shells or prying them open with their muscular feet.
Ecological Role
Acts as an active carnivorous predator in the intertidal reef ecosystem, helping to regulate barnacle and small mollusc populations.
Similar Species
Drupa morum (Mulberry Drupe) and Drupa rubusidaeus (Red-spiked Drupe), which can be distinguished by different spine arrangements, coloration, and aperture hues.
Beach Finding Tips
Look along rocky benches, tide pools, and reef flats at extreme low tide, specifically searching among reef rubble and crevices where heavy shells get wedged.
Notes
Hukilau Beach Oahu