''Elliptio'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

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, bival ...

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 e ...

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 diverse ...

, 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 and ...

, 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 angustata'' – Carolina lance * '' Elliptio arca'' – 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'' – 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 crassidens'' – Elephantear * '' Elliptio dariensis'' * '' Elliptio dilatata'' – Spike * '' Elliptio downiei'' – Satilla elephantear * '' Elliptio folliculata'' – pod lance * '' Elliptio fraterna'' – 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'' – 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'' – yellow lance * '' Elliptio mcmichaeli'' – fluted elephantear * '' Elliptio nigella'' – recovery pearly mussel, winged spike * '' Elliptio producta'' – Atlantic spike * '' Elliptio roanokensis'' – Roanoke slabshell * '' Elliptio shepardiana'' – Altamaha lance * '' Elliptio spinosa'' – Altamaha spinymussel, Georgia spinymussel * '' Elliptio steinstansana'' – Tar River spinymussel * '' Elliptio waltoni'' – 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