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.

Genera
Genera:
 * Euperinae
 * Byssanodonta d'Orbigny, 1846
 * Eupera Bourguignat, 1854
 * Sphaeriinae
 * Afropisidium Kuiper, 1962
 * Euglesa Jenyns, 1832
 * Musculium Link, 1807
 * Odhneripisidium Kuiper, 1962
 * Pisidium C. Pfeiffer, 1821
 * Sphaerium Scopoli, 1777
 * fossils
 * †Megasphaerioides Komatsu, J.-H. Chen & Q.-F. Wang, 2003
 * †Protosphaerium Hocknull, 2000
 * †Sphaericoncha Kolesnikov, 1980

Biology and ecology
Sphaeriidae are hermaphrodites with internal fertilization. Developing young are incubated within their mother (ovoviviparity), and newborn clams look like miniature copies of the adults.

Parasites and/or predators include the Sciomyzidae.