A small pearl oyster, flatter and far lighter than its blacklip relative, with a straight hinge line, short wing-like extensions at each end and a shell built of thin overlapping layers. The exterior is pale brown to greenish or yellowish with darker radial rays - the source of the name radiata - and the interior is lined with nacre. Width reaches about 10 cm (4 in). Byssal threads anchor it loosely to the bottom, and animals detached by surge can reattach elsewhere.
It lives on shallow rocky bottoms, rubble and in seagrass beds down to about 25 m (80 ft), often several together in the same patch, and filters plankton and suspended particles. This is the species that colonised the eastern Mediterranean after passing through the Suez Canal (🇪🇬 Egypt) from the 🌊 Red Sea, one of the earliest and most widespread Lessepsian migrants on record - it was recorded off 🇪🇬 Egypt within a few decades of the canal opening and now reaches as far west as 🇹🇳 Tunisia. It also produces small natural pearls and was the mainstay of the historic pearl fisheries of the Gulf and the Arabian coasts alongside the larger blacklip, though its shells are too thin to have been worth much for mother-of-pearl.
- small flat shell with a straight hinge and short wings
- pale brown to greenish with darker radial rays
- byssal threads anchoring it to rubble or seagrass
