Wing Oyster

Mollusc

Identification & Biology

• IdentificationA thin-shelled bivalve with an elongated, wing-like shape. The shell is translucent to pale brown, fragile, and flattened. It attaches to hard surfaces by byssus threads, often on gorgonian branches or other upright structures.
• SizeShell length up to 8 cm along the longest axis.
• Social HabitSolitary or in small groups. Attaches to elevated structures such as gorgonian sea fans, hydroids, and wire corals to access better water flow for filter feeding.
• HabitatRocky reefs, particularly on gorgonian fans, sea whips, and other upright organisms that project into the current.
• Depth10 to 80 m. Most common between 20 and 50 m.
• Feeds OnPlankton and suspended organic particles filtered from the water.
• DistributionEastern Atlantic and throughout the Mediterranean Sea. Present in Maltese waters.
• DescriptionPteria hirundo is an elegant bivalve that takes advantage of elevated positions on the reef by attaching itself to gorgonian sea fans and other upright organisms. This places it in a better flow of plankton-rich water than it would receive on the rock surface below. The thin, translucent shell is fragile and easily damaged, so it relies on its elevated, hard-to-reach position for protection from predators.