Fluted Giant Clam (also known as the Scaly Giant Clam or Small Giant Clam)
Phylum: Mollusca, Class: Bivalvia, Order: Cardiida, Family: Cardiidae, Subfamily: Tridacninae, Genus: Tridacna, Species: Tridacna squamosa · Cardiidae (Cockle family); specifically the Tridacninae (Giant Clam subfamily) · Bivalve (two-shelled). These specimens are individual valves (separated halves). The shape is roughly triangular to fan-shaped with deep fluted undulations.
Species
Tridacna squamosa (Confidence: 95%)
Shell Type
Bivalve (two-shelled). These specimens are individual valves (separated halves). The shape is roughly triangular to fan-shaped with deep fluted undulations.
Family
Cardiidae (Cockle family); specifically the Tridacninae (Giant Clam subfamily)
Size
The central specimen appears to be approximately 8-10 inches (20-25 cm) in length. This is a mid-sized adult; the species can grow up to 16 inches (40 cm).
Color & Pattern
Naturally grayish-white to cream. The exterior shows typical calcification and some weathering, likely sun-bleached or cleaned. In life, the interior is a smooth, glossy porcelain white. These specimens lack the vibrant mantle colors (blues, greens) which only exist in the living tissue.
Rarity
Common in the wild and in the shell trade, but strictly regulated. As beach finds, they are uncommon as the heavy shells usually stay on the reef unless moved by storms.
Habitat
Marine; found in shallow coral reefs and lagoons at depths of 1 to 20 meters. They prefer areas with high water clarity to allow sunlight for their symbiotic algae.
Geographic Range
Indo-Pacific region: stretching from the Red Sea and East Africa across to the Marshall Islands and Polynesia, and from southern Japan to northern Australia.
Description
A heavy, thick-walled bivalve characterized by 4 to 6 large, prominent radial folds (ribs). The most striking feature consists of the 'flutes'—large, leaf-like scales or scutes that protrude horizontally from the ribs. The margins are deeply crenulated, allowing the two valves to interlock tightly when closed.
Key Features
Distinguished by the presence of large, well-spaced epidermal scales (scutes) and a relatively small byssal opening (the gap near the hinge) compared to other Tridacna species.
Collector Value
Low to Moderate ($20 - $60 USD for these specific weathered valves). Large, pristine specimens with intact colorful scutes are highly prized. Note: This species is listed under CITES Appendix II, meaning international trade is strictly regulated.
Condition Notes
Fair to Good. These are 'dead-taken' or weathered beach specimens. The scutes are largely worn down or broken off, which is typical for shells tumbled by waves. A 'Gem' specimen would have long, delicate, protruding scales intact. Significant calcification is visible on the surface.
Interesting Facts
These clams are 'solar powered.' They host symbiotic algae called zooxanthellae in their fleshy mantle, which provide the clam with nutrients through photosynthesis. In return, the clam provides the algae with a safe home and sunlight access.
Ecological Role
Important reef builders and water filters. Their large bodies provide habitat for smaller organisms, and they contribute to the calcium carbonate structure of the reef. They are currently threatened by overfishing and habitat loss.
Similar Species
Tridacna maxima (Small Giant Clam), which has much smaller scales and a more elongated shape, and Tridacna gigas, which is significantly larger and lacks the prominent leaf-like scales.
Beach Finding Tips
Look in protected lagoon areas or reef flats after significant storms. They are often found partially embedded in coral rubble or sand near the reef edge.
Notes
Pass