Mactridae

Mactridae Temporal range: Cretaceous to Present
Shell of Spisula solida
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Bivalvia
Order:	Veneroida
Family:	Mactridae Lamarck, 1809
Genera
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Mactridae, common name the trough shells or duck clams, is a family of saltwater clams, marine bivalve mollusks in the order Veneroida.

These clams have two short siphons, each with a horny sheath. The shell is shaped like a rounded-cornered equilateral triangle and there is a slight gape at the posterior. Each valve bears two cardinal teeth with four lateral teeth on the right valve and two on the left. The foot is white and wedge-shaped. They mostly inhabit the neritic zone.

Trough shells burrow in sand or fine gravel and never in muddy substrates.

According to WoRMS (2012), this family contains 37 genera:

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