Jewel Box (specifically the Leafy Jewel Box)
Phylum: Mollusca, Class: Bivalvia, Order: Venerida, Family: Chamidae, Genus: Chama, Species: macerophylla · Chamidae (Jewel Box family) · Bivalve (thick-shelled, sedentary clam). This is a single valve (one half), likely the upper/free valve, featuring a rounded, fan-like shape with scaly projections.
Species
Chama macerophylla
Shell Type
Bivalve (thick-shelled, sedentary clam). This is a single valve (one half), likely the upper/free valve, featuring a rounded, fan-like shape with scaly projections.
Family
Chamidae (Jewel Box family)
Size
Approximately 15-20mm (0.6-0.8 inches). This is a juvenile or smaller specimen; adults typically reach 1-3 inches (25-75mm).
Color & Pattern
Predominantly white to off-white. This specimen appears heavily beach-worn and sun-bleached, which has obscured the natural vibrant pigments (typically lemon yellow, lavender, or reddish-pink) often found in live Jewel Boxes.
Rarity
Common. They are frequently found on Caribbean beaches, though perfectly preserved specimens with intact leafy 'frills' are harder to locate.
Habitat
Intertidal to deep water (up to 300 feet). They are sessile organisms that cement one valve permanently to hard substrates like coral reefs, rocks, shipwrecks, or other shells.
Geographic Range
Western Atlantic; ranging from North Carolina and Florida, through the Gulf of Mexico, Caribbean (including Cancun), and south to Brazil.
Description
A thick, rugged bivalve known for its 'leafy' or 'spiculated' sculpture. Even in this worn state, the shell exhibits radial rows of flattened, scale-like processes. The interior (if visible) would show a finely crenulated margin and an unusual hinge with a large, curved tooth.
Key Features
The diagnostic features are the heavy, unequal valves and the presence of irregular, flattened foliations (scales). Its 'cemented' growth habit often leaves a scar on the lower valve, while the upper valve (like this one) develops more decorative sculpture.
Collector Value
Low (under $5 USD). Because it is a worn, small specimen of a common species, it holds more sentimental value as a beach find than commercial market value. Pristine, colorful 'Gem' specimens with long spines are more desirable.
Condition Notes
Fair to Poor for a collector; Good for a personal souvenir. The shell is 'beach-worn,' meaning the delicate leafy edges have been eroded by wave action and sand. The lack of color suggests it has been dead for some time. No visible predator boreholes.
Interesting Facts
Jewel Boxes are the 'oysters' of the tropical reef; they cannot move once they attach to a spot as juveniles. Their common name comes from the colorful, boxy appearance of the closed valves which can look like a small encrusted treasure chest.
Ecological Role
Filter feeders that help clear the water of organic particles. Their rugged shells provide a hard micro-habitat for other smaller organisms like encrusting bryozoans and algae to grow upon.
Similar Species
Arcinella cornuta (Spiny Jewel Box) which has more distinct, upright spines, and Chama congregata (Little Corrugated Jewel Box) which is smaller and less leafy.
Beach Finding Tips
In Cancun and the Yucatan, look for these in the 'shell hash' piles at the high-tide line after a storm. They are heavy for their size, so they often settle in areas where pebbles and broken coral accumulate.
Notes
Cancun