Coquina Clam (also known as Butterfly Shell, Pipi, or Squirter Clam)
Phylum: Mollusca, Class: Bivalvia, Order: Cardiida, Family: Donacidae, Genus: Donax, Species: Donax variabilis · Donacidae (Bean Clam family) · Bivalve (two-shelled), whole shell, wedge or oval shape
Species
Donax variabilis
Shell Type
Bivalve (two-shelled), whole shell, wedge or oval shape
Family
Donacidae (Bean Clam family)
Size
Approximately 0.75 inches (about 20 mm) in length, which is typical for an adult of this species. Adults generally range from 0.5 to 1 inch.
Color & Pattern
Displays a vibrant gradient and natural glossy finish. The umbo area (beak) is a dark purplish-gray, fading smoothly into warm golden-tan and yellowish tones toward the ventral margin. Fine, concentric growth lines are clearly visible, crossed by very faint radial striations.
Rarity
Very Common
Habitat
Inhabits high-energy sandy ocean beaches in the intertidal zone, where it burrows rapidly into the sand just below the surf line.
Geographic Range
Western Atlantic and Gulf of Mexico, ranging from Virginia down to Florida and throughout the Gulf coast.
Description
A charming, wedge-shaped bivalve with a smooth, porcelain-like exterior and a slightly asymmetrical outline. The shell features prominent concentric growth rings and exhibits a classic color polymorphism ranging from purples and blues to yellows, oranges, and whites. The margins are tightly fitting and finely crenulated inside.
Key Features
Wedge-shaped profile, asymmetrical outline with the umbo offset toward one end, smooth glossy surface with fine concentric growth lines, and incredible color variation.
Collector Value
Low monetary value due to extreme abundance, but highly prized for beach crafts, decorative mosaics, and beginner shell collections because of their dazzling array of colors.
Condition Notes
Gem condition. The shell is fully intact with both valves presumably joined (or a pristine single valve), retaining its natural glossy sheen, vibrant coloration, and unblemished margins with no visible wear or predation holes.
Interesting Facts
Coquina clams are famous for their ability to rapidly re-bury themselves in the sand using their muscular foot when washed out by waves. They feed by filtering microscopic plankton and detritus from the water column as waves wash over them.
Ecological Role
Serves as a crucial food source for shorebirds, fish, and crabs. They help transfer energy from the water column to higher trophic levels on sandy beach ecosystems. Not currently regulated or endangered.
Similar Species
Donax fossor (Eastern Atlantic Coquina), which tends to be smaller and less brightly colored, and Donax denticulatus found further south in the Caribbean, which has more pronounced teeth along the inner margin.
Beach Finding Tips
Look along high-energy sandy beaches at low tide, particularly right at the swash zone where receding waves expose the sand. Watch for tiny bubbling holes or 'V' shapes in the sand as they burrow.