''Elliptio'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

of medium- to large-sized freshwater mussels, aquatic

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, biv ...

mollusk 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 es ...

s in the family

Unionidae The Unionidae are a family of freshwater mussels, the largest in the order Unionida, the bivalve molluscs sometimes known as river mussels, or simply as unionids. The range of distribution for this family is world-wide. It is at its most dive ...

, commonly known as the unionids, freshwater mussels or

naiad In Greek mythology, the naiads (; grc-gre, ναϊάδες, naïádes) are a type of female spirit, or nymph, presiding over fountains, wells, springs, streams, brooks and other bodies of fresh water. They are distinct from river gods, who ...

s. In contrast with many other groups of American Unionidae, the ''Elliptio'' species reach their greatest diversity in the Atlantic-draining rivers of Georgia and the Carolinas, and large parts of Florida. One species ranges north into New England and southern Canada, and two occur in the interior Mississippi drainages. Most ''Elliptio'' species have elongated shells, with silvery or purplish interior nacre beneath a thick

periostracum The periostracum ( ) is a thin, organic coating (or "skin") that is the outermost layer of the shell of many shelled animals, including molluscs and brachiopods. Among molluscs, it is primarily seen in snails and clams, i.e. in gastropods a ...

, and few reach large size or thickness. The genus name ''Elliptio'' refers to the elliptical shape of these bivalves. As of 2003 there are 36 species in the genus.

Species

* ''

Elliptio ahenea ''Elliptio ahenea'' is a species of bivalve in the family Unionidae. It is endemic to the United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily l ...

'' * ''

Elliptio angustata ''Elliptio angustata'' is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels. This species is endemic to the United States The United States of America (U.S.A. or USA), commonly know ...

'' – Carolina lance * ''

Elliptio arca The Alabama spike (''Elliptio arca'') is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels. This species is endemic to the United States, where it occurs in river systems in Mississippi, Alaba ...

'' – Alabama spike * ''

Elliptio buckleyi ''Elliptio'' is a genus of medium- to large-sized freshwater mussels, aquatic bivalve mollusks in the family Unionidae, commonly known as the unionids, freshwater mussels or naiads. In contrast with many other groups of American Unionidae, th ...

'' * ''

Elliptio chipolaensis The Chipola Slabshell is a part of the phylum: Mollusca and the class: Bivalvia. This species has suffered a large decrease with upwards of 75% of habitat lost. It is now confined to only a few remnant sites in small drainage from the Chipola river ...

'' – Chipola slabshell * ''

Elliptio complanata The eastern elliptio (''Elliptio complanata'') is a freshwater mussel in the Unionidae family, native to Canada and the United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or Amer ...

'' – Eastern elliptio * ''

Elliptio congaraea ''Elliptio congaraea'', the Carolina slabshell, is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels. Distribution This species is endemic Endemism is the state of a species being found ...

'' * ''

Elliptio crassidens ''Elliptio crassidens'', the elephant-ear, is a species of freshwater mussel, an aquatic bivalve mollusk in Unionidae, the river-mussel family. The elephant-ear possesses a thick triangular shell which may be up to six inches long. The outside ...

'' – Elephantear * ''

Elliptio dariensis ''Elliptio dariensis'' is a species of freshwater mussel, an aquatic bivalve Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally comp ...

'' * ''

Elliptio dilatata ''Elliptio'' is a genus of medium- to large-sized freshwater mussels, aquatic bivalve mollusks in the family Unionidae, commonly known as the unionids, freshwater mussels or naiads. In contrast with many other groups of American Unionidae, th ...

'' – Spike * ''

Elliptio downiei ''Elliptio downiei'' is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels. This species is endemic to the United States The United States of America (U.S.A. or USA), commonly known as ...

'' – Satilla elephantear * ''

Elliptio folliculata ''Elliptio folliculata'' is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels. This species is endemic to the United States The United States of America (U.S.A. or USA), commonly know ...

'' – pod lance * ''

Elliptio fraterna The brother spike (''Elliptio fraterna'') is a species of freshwater mussel the family Unionidae, the river mussels. This species is endemic Endemism is the state of a species being found in a single defined geographic location, such as an ...

'' – brother spike * ''

Elliptio fumata ''Elliptio'' is a genus of medium- to large-sized freshwater mussels, aquatic bivalve mollusks in the family Unionidae, commonly known as the unionids, freshwater mussels or naiads. In contrast with many other groups of American Unionidae, th ...

'' * ''

Elliptio hopetonensis ''Elliptio hopetonensis'' is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels. This species is endemic to the United States The United States of America (U.S.A. or USA), commonly kno ...

'' – Altamaha slabshell * ''

Elliptio icterina ''Elliptio'' is a genus of medium- to large-sized freshwater mussels, aquatic bivalve mollusks in the family Unionidae, commonly known as the unionids, freshwater mussels or naiads. In contrast with many other groups of American Unionidae, th ...

'' – variable spike * ''

Elliptio lanceolata The yellow lance, scientific name ''Elliptio lanceolata'', is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels. This species is endemic to the United States The United States of Ame ...

'' – yellow lance * ''

Elliptio mcmichaeli ''Elliptio mcmichaeli'', the fluted elephantear, is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels. This species is endemic to the Escambia and Choctawhatchee River systems in the southeas ...

'' – fluted elephantear * ''

Elliptio nigella ''Elliptio nigella'', the winged spike or recovery pearly mussel, is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels. This species is endemic to the United States. It was thought to be extin ...

'' – recovery pearly mussel, winged spike * ''

Elliptio producta ''Elliptio producta'', also known as the Atlantic spike, is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels. This species is endemic to the Eastern United States. It occurs on the Atlantic co ...

'' – Atlantic spike * ''

Elliptio roanokensis ''Elliptio'' is a genus of medium- to large-sized freshwater mussels, aquatic bivalve mollusks in the family Unionidae, commonly known as the unionids, freshwater mussels or naiads. In contrast with many other groups of American Unionidae, ...

'' – Roanoke slabshell * ''

Elliptio shepardiana ''Elliptio shepardiana'',, the Altamaha lance, is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels, naiads or unionids. This species is endemic to the United States The United Stat ...

'' – Altamaha lance * ''

Elliptio spinosa ''Elliptio spinosa'', the Altamaha spinymussel, is an endangered species of freshwater mussel in the family Unionidae. They live in southeastern Georgia in the Altamaha river and its tributaries. It is one of three species of North American spi ...

'' – Altamaha spinymussel, Georgia spinymussel * ''

Elliptio steinstansana The Tar River spiny mussel or Tar River spinymussel (''Elliptio steinstansana'') is a species of freshwater mussel in the family Unionidae, the river mussels. This species is endemic to North Carolina in the United States. This species is endemic ...

'' – Tar River spinymussel * ''

Elliptio waltoni ''Elliptio ahenea'' is a species of bivalve in the family Unionidae. It is endemic to the United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily l ...

'' – Florida lance

References

External links

Electric Elliptio Land.
Division of Molluscs, Department of Evolution, Ecology, and Organismal Biology, The Ohio State University. Bivalve genera Taxa named by Constantine Samuel Rafinesque Taxonomy articles created by Polbot {{Unionidae-stub