Mactra

Mactra Temporal range: Eocene–Present PreꞒ Ꞓ O S D C P T J K Pg N
Mactra stultorum
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Bivalvia
Order:	Venerida
Superfamily:	Mactroidea
Family:	Mactridae
Subfamily:	Mactrinae
Genus:	Mactra Linnaeus, 1767
Species
See text
Synonyms
Colorimactra Iredale, 1929 Deikea Mayer-Eymar, 1872 Mactra (Mactra) Linnaeus, 1767· accepted, alternate representation Mactra (Maorimactra) Finlay, 1928· accepted, alternate representation Mactra (Nannomactra) Iredale, 1930· accepted, alternate representation Nannomactra Iredale, 1930 Telemactra Iredale, 1929 Trigonella da Costa, 1778

Mactra is a large genus of medium-sized marine bivalve mollusks or clams, commonly known as trough shells or duck clams. Mactra is the type genus within the family Mactridae.^[1]

The word "trough" in the common name refers to the fact that all Mactra shells have a large ligamental pit at the hinge line, which in life contains a large internal ligament. Most bivalves in other families have an external ligament instead.