Spiny Jewel Box (also known as the Little Spiny Jewel Box or Leafy Jewel Box)
Phylum: Mollusca, Class: Bivalvia, Order: Venerida, Family: Chamidae, Genus: Arcinella, Species: Arcinella cornuta · Chamidae (Jewel Box family) · Bivalve (two-shelled clam), whole shell, triangular to rounded fan shape
Species
Arcinella cornuta
Shell Type
Bivalve (two-shelled clam), whole shell, triangular to rounded fan shape
Family
Chamidae (Jewel Box family)
Size
Approximately 1 to 1.5 inches in length and width, which is average for this species. Adults typically range from 1 to 2 inches.
Color & Pattern
Creamy off-white to pale yellowish-brown base coloration, monochromatic with some natural sand staining. Colors appear natural and slightly weathered from wave action. The interior is generally smooth and white with a porcelain-like texture.
Rarity
Common to Uncommon, depending on the specific beach and local diving conditions; intact specimens with all spines preserved require some searching.
Habitat
Found in shallow marine waters to moderate depths, typically inhabiting hard substrates, coral reefs, rubble zones, and attached to rocks or shells in sub-tidal environments.
Geographic Range
Western Atlantic Ocean, including North Carolina, Florida, the Gulf of Mexico, the Caribbean Sea, and south to Brazil.
Description
A stunning and heavily sculpted bivalve, the Spiny Jewel Box is instantly recognizable by its thick, robust shell adorned with numerous hollow, pointed spines radiating outward in distinct radial rows. The overall shape is somewhat globular and triangular with a prominent umbo. The texture is extremely rough and prickly, giving it a highly ornate, rustic, and organic architectural appearance.
Key Features
Distinguished by its thick, cemented bivalve nature, prominent radial ribs, and the distinct presence of long, hollow, needle-like spines covering the exterior surface.
Collector Value
Moderately high collectibility value among shell enthusiasts due to the intricate beauty and fragility of the spines. Specimens with all spines fully intact command higher interest and value compared to heavily worn beach-tumbled fragments.
Condition Notes
Good to Fine condition. The shell is largely intact with most of its delicate hollow spines well-preserved, showing only minor wear on the outermost tips due to natural tumbling.
Interesting Facts
Unlike free-moving clams, jewel box shells cement one of their valves directly onto hard surfaces (like rocks or coral) early in life, spending the rest of their lives permanently attached in place. Their elaborate spiny ornamentation helps deter hungry predators and provides camouflage among rubble.
Ecological Role
Acts as a filter feeder, helping to clear organic particulate matter from the water column. Provides micro-habitats and shelter for small invertebrates among its spiny forest. Generally not commercially threatened.
Similar Species
Arcinella arcinella (Southern Jewel Box), which tends to have slightly different spine arrangements and geographical variations. Distinguished primarily by rib count and spine morphology.
Beach Finding Tips
Best found by beachcombing after heavy storms or rough seas in regions bordering the Gulf of Mexico and Florida, particularly around shell-rich drift lines and rocky outcrops at low tide.