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: T. squamosa · Cardiidae (Cockle family); Subfamily Tridacninae (Giant Clam family) · Bivalve (two-shelled mollusk); specifically a single valve (half of a shell) displaying a fan-shaped, corrugated profile with prominent scales.
Species
Tridacna squamosa
Shell Type
Bivalve (two-shelled mollusk); specifically a single valve (half of a shell) displaying a fan-shaped, corrugated profile with prominent scales.
Family
Cardiidae (Cockle family); Subfamily Tridacninae (Giant Clam family)
Size
Based on the wooden plate (standard decorative size), this valve is approximately 8 to 10 inches (20-25 cm) in length. This is a mid-sized specimen; adults typically reach 12-16 inches.
Color & Pattern
The exterior is ivory to grayish-white, appearing largely sun-bleached or weathered. In life, these shells often display orange, pink, or yellow hues. The interior is a smooth, glossy porcelaneous white. The periostracum is absent, which is common in beach-worn or cleaned specimens.
Rarity
Uncommon in the wild due to over-harvesting; Common in the classic shell trade. As a beach find, it is rare to find a large, intact specimen with delicate scales still attached.
Habitat
Found in shallow marine waters on coral reefs, typically attached to the substrate by a byssus or wedged between coral heads in depths up to 20 meters. They thrive in clear, sunlit waters to support their symbiotic algae.
Geographic Range
Indo-Pacific region, spanning from the Red Sea and East Africa across to the Marshall Islands and further east to the Tuamotu Archipelago.
Description
A robust, heavy bivalve featuring 4 to 6 deeply folded, radial ribs. The hallmark of the species is the large, leaf-like 'flutes' or scales (scutes) that project horizontally from the ribs. The margins are strongly undulated, interlocking perfectly with the opposing valve when closed.
Key Features
Large, well-spaced leaf-like flutes (scales) on the radial ribs; a relatively small byssal opening compared to other Tridacna species; symmetric fan shape with deep corrugations.
Collector Value
Moderate ($30 - $75 USD for a single valve of this size). Value increases significantly for matched pairs (both halves) or specimens with perfectly preserved, large, colorful flutes. Note that large Tridacna species are protected under CITES Appendix II.
Condition Notes
Fair to Good. The shell shows significant weathering and some erosion of the delicate flutes, which are prone to breaking. A small barnacle is attached to one of the ribs, indicating it spent time submerged as an empty shell. Collectibility is moderate as a decorative piece rather than a 'Gem' specimen.
Interesting Facts
Like other giant clams, Tridacna squamosa hosts zooxanthellae (symbiotic algae) in its mantle tissue. The algae provide the clam with nutrients via photosynthesis, while the clam provides the algae with a safe home and sunlight access. Large specimens can live for decades.
Ecological Role
Critical reef builders and water filters. They provide habitat for various small reef organisms. Currently, they are listed as 'Vulnerable' or 'Conservation Dependent' in many regions due to the aquarium trade and food harvesting.
Similar Species
Tridacna maxima (Small Giant Clam), which has much smaller, closer-set scales and a larger byssal opening; and Tridacna gigas, which lacks prominent flutes and grows significantly larger.
Beach Finding Tips
Look for heavy, white objects in the lagoon debris and reef flats of the Indo-Pacific after storms. Because they are heavy, they do not wash up as easily as smaller shells; they are more often found by diving or snorkeling in reef areas.
Notes
Pass