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THYASIRIDAE |
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Mendicula memorata Iredale, 1924 Description: Shell very small, well inflated. Shape almost circular; umbo on midline; lunule large, shallow, poorly defined. Wide, shallow groove from umbo to ventral margin posteriorly. Exterior with irregular concentric growth ridges, no radial sculpture; often encrusted with a thick brown sandy mass that is not a periostracum. Interior with anterior and posterior muscle scars sub-circular, pallial line continuous (Fig. 3), margin smooth. Hinge without teeth. Ligament in long, narrow groove. Shell colour white. Size: Up to 7.5 mm high, usually about 3 mm. Distribution: Known from Newcastle, NSW, southwards to eastern Bass Strait. Habitat: Subtidal, 300-1500 m depth. Most specimens are enclosed in a thick, hard, brown, sandy mass that is not a periostracum, that cracks and splits off when dry (Fig. 2). Synonymy: This species was first described as Lucina induta Hedley, 1907 but that name was preoccupied, and it was renamed Mendicula memorata Iredale, 1924. Fig. 1: Off Sydney, NSW, in 750 m depth (C.445227) Fig. 2: Off Wollongong, NSW, in 1200 m (C.452913) Fig. 3: East of Tathra, NSW, 329-375 m (C.452924) |
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