Family Mesodesmatidae - wedge clams

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Bivalvia
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Fresh : No | Brackish : Yes | Marine : Yes
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Shell equivalve, usually thick and heavy, more or less compressed laterally, inequilateral, elongate ovate or subtrigonal to wedge-shaped in outline. Umbones opisthogyrate. Outer surface smooth or mostly concentrically sculptured, with a well-developed and often glossy periostracum. External ligament short and not prominent, communicating with a strong internal ligament fitting in each valve in a deep pit of the hinge plate. Hinge with 1 or 2 cardinal teeth and more or less developed lateral teeth in each valve. Interior of shell porcelaneous. Two adductor muscle scars, subequal in size. Pallial line with a rather short sinus. Internal margins smooth. Gills of eulamellibranchiate type, with folded branchial sheets. Foot strong and subtrigonal, without a byssus. Siphons separate, naked, papillate on top. Mantle margins smooth, with an anteroventral gape. Suspension filter-feeding animals, actively burrowing in sandy bottoms; sexes separate; development with a free-swimming larval stage; locally collected as food by coastal people (Ref. 348).
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Ref.
[ e.g. 9948]                       
Glossary
                    [ e.g. cephalopods]


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