Sphaeriidae is a

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

of small to minute freshwater

bivalve Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bival ...

mollusc Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is esti ...

s in the order

Sphaeriida Sphaeriida is an order of bivalves belonging to the class Bivalvia. Families: * Neomiodontidae * Sphaeriidae Sphaeriidae is a family of small to minute freshwater bivalve molluscs in the order Sphaeriida. In the US, they are commonly known ...

. In the US, they are commonly known as pea clams or fingernail clams. Heard, William H. 1977. Reproduction of fingernail clams (Sphaeriidae: ''Sphaerium'' and ''Musculium''). Malacologia, 16: 421-455.

Genera

Genera: * Euperinae ** '' Byssanodonta'' d'Orbigny, 1846 ** ''

Eupera ''Eupera'' is a genus of bivalves belonging to the family Sphaeriidae. The species of this genus are found in America and Africa. Species: *'' Eupera bahamensis'' *''Eupera bahiensis'' *'' Eupera barbadensis'' *'' Eupera crassa'' *'' Euper ...

'' Bourguignat, 1854 * Sphaeriinae ** ''

Afropisidium ''Afropisidium'' is a genus of bivalves belonging to the family Sphaeriidae Sphaeriidae is a family of small to minute freshwater bivalve molluscs in the order Sphaeriida. In the US, they are commonly known as pea clams or fingernail clams. ...

'' Kuiper, 1962 ** ''

Euglesa ''Euglesa'' is a genus of bivalves belonging to the family Sphaeriidae Sphaeriidae is a family of small to minute freshwater bivalve molluscs in the order Sphaeriida. In the US, they are commonly known as pea clams or fingernail clams. Hea ...

'' Jenyns, 1832 ** ''

Musculium ''Musculium'' is a genus of small freshwater clams, aquatic bivalve molluscs in the family Sphaeriidae, the fingernail clams and pea clams. Species Species and subgenera within this genera include: Subgenus ''Musculium'' Link, 1807 * ''Muscu ...

'' Link, 1807 ** '' Odhneripisidium'' Kuiper, 1962 ** ''

Pisidium ''Pisidium'' is a genus of very small or minute freshwater clams known as pill clams or pea clams, aquatic bivalve molluscs in the family Sphaeriidae, the pea clams and fingernail clams. In some bivalve classification systems, the family S ...

'' C. Pfeiffer, 1821 ** ''

Sphaerium ''Sphaerium'' is a genus of very small freshwater clams, aquatic bivalve molluscs in the family Sphaeriidae, known as the fingernail clams. The small clams in this genus are unusual in that many of them, such as '' Sphaerium corneum'', can climb ...

'' Scopoli, 1777 * fossils ** †'' Megasphaerioides'' Komatsu, J.-H. Chen & Q.-F. Wang, 2003 ** †'' Protosphaerium'' Hocknull, 2000 ** †'' Sphaericoncha'' Kolesnikov, 1980

Biology and ecology

Sphaeriidae are

hermaphrodite In reproductive biology, a hermaphrodite () is an organism that has both kinds of reproductive organs and can produce both gametes associated with male and female sexes. Many Taxonomy (biology), taxonomic groups of animals (mostly invertebrate ...

s with internal fertilization. Developing young are incubated within their mother (

ovoviviparity Ovoviviparity, ovovivipary, ovivipary, or aplacental viviparity is a term used as a "bridging" form of reproduction between egg-laying oviparous and live-bearing viviparous reproduction. Ovoviviparous animals possess embryos that develop insi ...

), and newborn clams look like miniature copies of the adults.

Parasite Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has ...

s and/or predators include the

Sciomyzidae The family Sciomyzidae belongs to the typical flies (Brachycera) of the order Diptera. They are commonly called marsh flies, and in some cases snail-killing flies due to the food of their larvae. Here, the Huttoninidae, Phaeomyiidae and Tetan ...

References

{{Authority control Bivalve families