''Ellipsaria lineolata'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

freshwater mussel Freshwater bivalves are one kind of freshwater mollusc, along with freshwater snails. They are bivalves that live in fresh water as opposed to salt water, which is the main habitat type for bivalves. The majority of species of bivalve molluscs ...

, 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 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 ...

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 ...

, the river mussels. This is the sole species in the

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

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 ...

''Ellipsaria ''. This species is native to the drainage systems of the

Mississippi River The Mississippi River is the second-longest river and chief river of the second-largest drainage system in North America, second only to the Hudson Bay drainage system. From its traditional source of Lake Itasca in northern Minnesota, it f ...

, the

Mobile River The Mobile River is located in southern Alabama in the United States. Formed out of the confluence of the Tombigbee and Alabama rivers, the approximately river drains an area of of Alabama, with a watershed extending into Mississippi, Georg ...

, the

Tennessee River The Tennessee River is the largest tributary of the Ohio River. It is approximately long and is located in the southeastern United States in the Tennessee Valley. The river was once popularly known as the Cherokee River, among other names, ...

, and the

Cumberland River The Cumberland River is a major waterway of the Southern United States. The U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map, accessed June 8, 2011 river drains almost of southern Kentucky and ...

in 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 located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

. It exists in the midwestern United States, and has also been observed in the east coast and as far south as the

Gulf of Mexico The Gulf of Mexico ( es, Golfo de México) is an oceanic basin, ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of ...

. The common name of ''Ellipsaria lineolata'' is the Butterfly Mussel.

Description

''E. lineolata'' has a thick, fairly triangular shell with dorsal, anterior, and ventral margins that are rounded. The shells of males have a more compressed shape than that of females. Males' shells are also typically longer, growing up to 12.7 cm long compared to females, whose shells grow to around 7 cm long. The shells of most ''E. lineolata'' have a yellowish color on the outside, but some older mussels have a dark brown shell. The inside of the shell is white, and the hinge can sometimes be a dark green color. The sculpture of the beak contains double-looped, fine lines.

Usage and sonservation

As with several other freshwater mussel species, ''E. lineolata'' have been used to make pearl buttons. Today, ''E. lineolata'' and other mussels are sometimes used in the

cultured pearl Cultured pearls are formed within a cultured pearl sac with human intervention in the interior of productive living molluscs in a variety of conditions depending upon the mollusc and the goals. Just as the same as natural pearls, cultured pearls ...

industry. This species is considered critically imperiled in some states like Louisiana and Kansas. ''E. lineolata'' lives buried in sand or gravel substrates in large rivers with fast currents. Additionally, this species has been found in reservoirs in the Tennessee River. This species is a long-term brooder and may be found gravid during any month of the year. Since the primary habitat of this species is the Mississippi River basin, the declining conditions of this habitat pose a threat to the existence of this species. The movement of fish hosts to this mussel are blocked by channelization, dams, and dredging that increase siltation in the river. The host fish for ''E. lineolata'' is ''Aplonditus grunniens,'' or the

freshwater drum The freshwater drum, ''Aplodinotus grunniens'', is a fish endemic to North and Central America. It is the only species in the genus ''Aplodinotus'', and is a member of the family Sciaenidae. It is the only North American member of the group that ...

. ''E. lineolata'' have been increasingly affected by invasive species such as the

zebra mussel The zebra mussel (''Dreissena polymorpha'') is a small freshwater mussel. The species originates from the lakes of southern Russia and Ukraine, but has been accidentally introduced to numerous other areas and has become an invasive species in ma ...

, who attach to the outside of the butterfly mussel's shell in large numbers and cause suffocation.

References

Fauna of the United States Unionidae Bivalves described in 1820 Taxa named by Constantine Samuel Rafinesque Taxonomy articles created by Polbot {{Unionidae-stub