Tapestry Venus, Mud Cockle, or Paphia
Phylum: Mollusca, Class: Bivalvia, Order: Venerida, Family: Veneridae, Genus: Marcia, Species: Marcia hiantina · Veneridae (Venus Clams) · Bivalve (single valve shown); oval/sub-trigonal shape
Species
Marcia hiantina
Shell Type
Bivalve (single valve shown); oval/sub-trigonal shape
Family
Veneridae (Venus Clams)
Size
Estimated at 35-45mm in length. This is a standard adult size for this species which typically reaches up to 50-60mm.
Color & Pattern
Exterior shows a gradient of grayish-blue to dark charcoal bands near the margins, fading into a creamy white or pale yellowish-tan near the umbo (beak). Features concentric growth lines with a subtle 'tapestry' or zig-zag pattern typical of the family, though somewhat obscured by environmental staining.
Rarity
Common; very frequently found on mudflats and sandy beaches in Moreton Bay and along the Brisbane coast.
Habitat
Inhabits soft substrates such as sand, mud, and silty sand. Predominantly found in intertidal zones, estuaries, and shallow coastal waters often near mangroves.
Geographic Range
Indo-West Pacific region, ranging from Southeast Asia to Northern and Eastern Australia, including the Queensland coastline and Brisbane area.
Description
A sturdy, medium-sized bivalve with an inequilateral, oval-oblong shape. The shell is characterized by fine, crowded concentric ridges. The interior (not fully visible) usually has a smooth margin and a distinct pallial sinus.
Key Features
Distinguished by its 'inflated' appearance compared to other Venus clams, the smoothish but finely ridged concentric surface, and the characteristic blue-grey color zones common in specimens from muddy Brisbane waters.
Collector Value
Minimal financial value (less than $2 USD) due to its abundance, but of high educational value for local regional collections.
Condition Notes
Fair to Good. The shell is a single valve rather than a paired set. It shows some natural beach wear and minor erosion at the umbo. The dark staining is likely due to the anaerobic mud environment of the Sandgate/Brighton area.
Interesting Facts
These clams are edible and are commonly harvested as 'Pipis' or 'Cockles' in various cultures. They are excellent filter feeders that help maintain water clarity in estuarine environments.
Ecological Role
Primary consumer/suspension feeder. They filter plankton and organic detritus from the water column and serve as a vital food source for shorebirds and rays.
Similar Species
Katelysia rhytiphora (Grey Sand Cockle) which has more pronounced ridges, and various species of Tapes which often have more vivid 'v' shaped patterns.
Beach Finding Tips
Best found at Sandgate or Brighton during low tide, especially after a storm or strong swell. Look in the debris lines or walk the exposed mudflats near the tide line.
Notes
Brighton Sandgate beach Brisbane