Mactridae

Mactridae, common name the trough shells or duck clams, is a family of saltwater clams, marine bivalve mollusks in the order Venerida.

Mactridae Temporal range: Cretaceous to Present
Shell of Spisula solida
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Bivalvia
Order:	Venerida
Superfamily:	Mactroidea
Family:	Mactridae Lamarck, 1809
Genera
See text.

Description

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.^[1]

Ecology

Trough shells burrow in sand or fine gravel and never in muddy substrates.^[1]

Subfamilies and genera

Mactra stultorum

Lutraria lutraria

According to the World Register of Marine Species (2025), this family contains 56 genera and is split into the following subfamilies:^[2]

Subfamily Darininae

• †Darcinia Clark, 1946
• Darina J. E. Gray, 1853

Subfamily Lutrariinae

• Eastonia J. E. Gray, 1853
• Heterocardia Deshayes, 1855
• Lutraria Lamarck, 1799
• Meropesta Iredale, 1929
• Standella J. E. Gray, 1853
• Tresus J. E. Gray, 1853^[3]
• Zenatia J. E. Gray, 1853
• Zenatina Gill & Darragh, 1963

Subfamily Mactrinae

• †Allomactra Tomlin, 1931
• Austromactra Iredale, 1930
• Barymactra Cossmann, 1909
• Coelomactra Dall, 1895
• Crassula Marwick, 1948
• Cyclomactra Dall, 1895^[4]
• Diaphoromactra Iredale, 1930
• Harvella J. E. Gray, 1853
• Huberimactra Cosel & Gofas, 2018
• Leptospisula Dall, 1895
• Mactra Linnaeus, 1767^[3]
• Mactrella J. E. Gray, 1853
• Mactrellona J. G. Marks, 1951
• Mactrinula J. E. Gray, 1853^[5]
• Mactromeris Conrad, 1868
• Mactrotoma Dall, 1894^[3]
• Maorimactra H. J. Finlay, 1928
• Mulinia J. E. Gray, 1837^[3]
• Oxyperas Mörch, 1853
• †Pseudocardium Gabb, 1866
• Rangia Desmoulins, 1832^[3]
• †Sarmatimactra Korobkov, 1954
• Scalpomactra H. J. Finlay, 1928
• Scissodesma Gray, 1837
• Simomactra Dall, 1894^[3]
• Spisula J. E. Gray, 1837^[3]
• Trinitasia Maury, 1928
• Tumbeziconcha Pilsbry & Olsson, 1935
• Mactrona Marwick, 1952
• Petromactra Saul, 1973

Subfamily Resaniinae

• Resania J. E. Gray, 1853

Subfamily Tanysiphoninae

• Tanysiphon W. H. Benson, 1858

Incertae sedis

• †Aktschagylia Starobogatov, 1970
• †Aliomactra Stephenson, 1952
• †Andrussella Korobkov, 1954
• †Avimactra Andrusov, 1905
• †Caspimactra A. A. Ali-Zade & Kabakova, 1969
• †Chersonimactra Paramonova, 1978
• †Cryptomactra Andrussow, 1902
• †Cymbophora Gabb, 1869
• †Eopapyrina Woodring, 1982
• †Geltena Stephenson, 1946
• †Ionesimactra Signorelli, 2023
• †Kirghizella Andrusov, 1902
• †Mactrodesma Conrad, 1869
• Mactrona Marwick, 1952
• †Mulinoides Olsson, 1944
• †Nelltia Stephenson, 1952
• †Nymphactra Stilwell & Zinsmeister, 1992
• †Ovamactra Woodring, 1982
• Petromactra Saul, 1973
• †Planimactra Ionesi, 1986
• †Podolimactra Ionesi, 1986
• †Praerangia Cossmann, 1908
• †Priscomactra Stephenson, 1952
• †Pseudomactra Steklov, 1960
• †Pteroluter Saul, 1973
• †Stereomactra Stewart, 1930
• †Stiphromactra Böhm, 1929
• †Tenuimactra Garvie, 1996
• †Willimactra Saul, 1973
• †Zenatiopsis Tate, 1880