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Family Donacidae - donax clams
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Class |
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Bivalvia |
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No. of Genera in Ref. |
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No. of Species in Ref. |
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Environment |
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Fresh : Yes |
Brackish : Yes |
Marine : Yes |
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Remark |
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Shell equivalve or nearly so, usually solid, compressed, trigonal to wedge-shaped, not gaping; inequilateral, with a shorter and somewhat obliquely truncate posterior end. Umbones opisthogyrate. Posterodorsal slope often differently sculptured than the rest of the shell. Ligament external, in a groove behind umbones. Hinge with 2 small cardinal teeth in each valve, the strongest commonly bifid, and more or less developed lateral teeth. Interior of shell porcelaneous. Two adductor muscle scars, about equal in size. Pallial sinus deep, largely confluent ventrally with the pallial line. Cruciform muscle scars obscure. Internal; margins crenulated or smooth. Gills or eulamellibranchiate type, smooth or folded. Foot strong, laterally compressed. Siphons quiet short, naked, separated to their base, with 6 lobes on top. Cruciform muscles present. Mantle margins widely open anteroventrally. Quick shallow burrowers living in sandy bottoms, under the influence of surf. Both suspension and deposit feeding animals. Sexes separate. Development with a free-swimming larval stage. Locally exploited by coastal people in the area. A single species is know to be collected in fairly large quantities in the Philippines (Ref. 348). |
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