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MARGARITIDAE |
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Pinctada margaritifera (Linnaeus, 1758) Description: Shape Shell oblique when juvenile (Fig. 1), almost circular when adult (Fig. 2), with left valve more inflated than right; umbo near anterior end of dorsal margin; dorsal margin straight, anterior margin with deep byssal notch in right valve, posterior margin straight or concave, ventral margin rounded. Hinge line straight, ligament in a broad triangular pit behind umbo. Interior nacreous silver-grey, with black edge and a wide non-nacreous margin banded light and dark; muscle scar crescent-shaped. Exterior with concentric foliaceous laminae with foliaceous processes in radial rows. Shell colour variable; usually dark with white rays. Size: Up to 300 mm in length, but usually much smaller. Distribution: Indo-West Pacific, from east Africa through the Indian Ocean and western Pacific Ocean, to central Pacific. In Australia, from Geraldton, WA, around northern Australia, to northern NSW. Habitat: Occurs in intertidal and subtidal zones down to 66 m, attached by byssus to hard substrates. Comparison: See P. fucata. Remarks: This is the Black-lip Pearl Shell, collected for mother-of-pearl shell and farmed for pearl production. Fig. 1: Minnie Waters, East of Grafton, NSW (C.300896) Fig. 2: Cairns Reef, SE of Cooktown, Qld (C.104772) |
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