''Epioblasma'' is a North American

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

freshwater mussel Freshwater bivalves are molluscs of the order Bivalvia that inhabit freshwater ecosystems. They are one of the two main groups of freshwater molluscs, along with freshwater snails. The majority of bivalve molluscs are saltwater species that l ...

aquatic Aquatic means relating to water; living in or near water or taking place in water; does not include groundwater, as "aquatic" implies an environment where plants and animals live. Aquatic(s) may also refer to: * Aquatic animal, either vertebrate ...

bivalve Bivalvia () or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class (biology), class of aquatic animal, aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed b ...

mollusk Mollusca is a phylum of protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant species of molluscs are recognized, making it the second-largest animal phylum after Arthropoda. The ...

s in the family

Unionidae The Unionidae are a Family (biology), 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 a ...

, the river mussels. Most of the species in this genus have been lost in modern times, and the entire genus is threatened with the possibility of extinction.

Reproduction

All Unionidae are known to make use of the gills, fins, or skin of a host fish for nutrients during the larval

glochidia The glochidium (plural glochidia) is a microscopic larval stage of some freshwater mussels, aquatic bivalve mollusks in the families Unionidae and Margaritiferidae, the river mussels and European freshwater pearl mussels. These larvae are t ...

stage. It was discovered in 2004 that female ''Epioblasma'' in the subgenus ''Torulosa'' transfer their parasitic larvae to the host fish by snapping onto the head of the fish and pumping the larvae into the host fish's gills. While using bait to lure host fish towards the larvae is common in the family Unionidae, this was the first time that "fish snapping" behavior had been observed. Examination of other species within the genus ''Epioblasma'' may further reveal unusual reproductive mechanisms.

Taxonomy of the genus ''Epioblasma''

Note: Taxa with a "

† A dagger, obelisk, or obelus is a typographical mark that usually indicates a footnote if an asterisk has already been used. The symbol is also used to indicate death (of people) or extinction (of species or languages). It is one of the mo ...

" symbol are extinct due to human activity *Subgenus †''Epioblasma'' **†''

Epioblasma flexuosa ''Epioblasma flexuosa'', the arcuate pearly mussel or leafshell, was a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels. This species was endemic to the United States, where it was found in the m ...

'' - Leafshell **†'' Epioblasma lewisii'' - Forkshell **†''

Epioblasma stewardsonii ''Epioblasma stewardsonii'', the Cumberland leafshell or Steward's pearly mussel, is an extinct species of freshwater mussel in the family Unionidae. This species was endemic to the drainages of the Cumberland River and the Tennessee River in th ...

'' - Cumberland leafshell *Subgenus ''Pilea'' **†'' Epioblasma haysiana'' - Acornshell **''

Epioblasma obliquata ''Epioblasma obliquata'', commonly called the catspaw, is a species of freshwater mussel. It is native to eastern North America, where it is classified as endangered under the Endangered Species Act. There are two subspecies, each with distinct m ...

'' ***''Epioblasma obliquata obliquata'' - Purple catspaw ***''Epioblasma obliquata perobliqua'' - White catspaw **†'' Epioblasma personata'' - Round combshell *Subgenus ''Plagiola'' **†'' Epioblasma arcaeformis'' - Sugarspoon **''

Epioblasma brevidens ''Epioblasma brevidens'', the Cumberlandian combshell, is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae. This species is endemic to the United States, found mainly in the states of Tennessee and Virginia. Th ...

'' - Cumberlandian combshell **†''

Epioblasma lenior ''Epioblasma lenior'', the narrow catspaw or Stone's pearly mussel, was a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels. This species was endemic to the Tennessee River system in the United S ...

'' - Narrow catspaw **'' Epioblasma metastriata'' - Upland combshell **'' Epioblasma othcaloogensis'' - Southern acornshell **'' Epioblasma penita'' - Southern combshell *Subgenus ''Torulosa'' **''

Epioblasma ahlstedti ''Epioblasma ahlstedti'', commonly called the Duck River dartersnapper, is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels. It is native to Alabama and Tennessee in the southeastern United St ...

'' - Duck River oyster mussel **†''

Epioblasma biemarginata ''Epioblasma biemarginata'', the angled riffleshell, was a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels. It is now extinct. This species was endemic to the drainages of the Cumberland River ...

'' - Angled riffleshell **''

Epioblasma capsaeformis The oyster mussel (''Epioblasma capsaeformis'') is a rare species of freshwater mussel in the family Unionidae. This aquatic bivalve mollusk is native to the Cumberland and Tennessee River systems of Kentucky, Tennessee, Alabama, and Virginia in ...

'' - Oyster mussel **†''

Epioblasma cincinnatiensis ''Epioblasma'' is a North American genus of freshwater mussels, aquatic bivalve mollusks in the family Unionidae, the river mussels. Most of the species in this genus have been lost in modern times, and the entire genus is threatened with the pos ...

'' - Cincinnati Riffleshell **''

Epioblasma florentina ''Epioblasma'' is a North American genus of freshwater mussels, aquatic bivalve mollusks in the family Unionidae, the river mussels. Most of the species in this genus have been lost in modern times, and the entire genus is threatened with the pos ...

'' ***''

Epioblasma florentina aureola ''Epioblasma'' is a North American genus of freshwater mussels, aquatic bivalve mollusks in the family Unionidae, the river mussels. Most of the species in this genus have been lost in modern times, and the entire genus is threatened with the pos ...

'' - Golden riffleshell ***''

Epioblasma florentina curtisii ''Epioblasma'' is a North American genus of freshwater mussels, aquatic bivalve mollusks in the family Unionidae, the river mussels. Most of the species in this genus have been lost in modern times, and the entire genus is threatened with the pos ...

'' - Curtis pearlymussel ***†''

Epioblasma florentina florentina ''Epioblasma'' is a North American genus of freshwater mussels, Aquatic animal, aquatic bivalve mollusks in the family Unionidae, the river mussels. Most of the species in this genus have been lost in modern times, and the entire genus is threate ...

'' - Yellow blossom ***''

Epioblasma florentina walkeri ''Epioblasma walkeri'', common name the tan riffleshell, is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels. Many scientists now recognize this mussel as synonymous or a subspecies of the pre ...

'' - Tan riffleshell **†''

Epioblasma propinqua ''Epioblasma propinqua'', the Tennessee riffleshell or nearby pearly mussel, is an extinct species of freshwater mussel in the family Unionidae. It was endemic to the United States, where it was found in the drainages of the Cumberland River, Ohi ...

'' - Tennessee riffleshell **†'' Epioblasma sampsonii'' - Wabash riffleshell **'' Epioblasma torulosa'' ***†'' Epioblasma torulosa gubernaculum'' - Green blossom ***'' Epioblasma torulosa rangiana'' - Northern riffleshell ***†'' Epioblasma torulosa torulosa'' - Tubercled blossom **†'' Epioblasma turgidula'' - Turgid riffle shell *Subgenus ''Truncillopsis'' **''

Epioblasma triquetra ''Epioblasma triquetra'', common name the snuffbox mussel, is a species of freshwater mussel, a mollusk in the family Unionidae. It is native to eastern North America, where it is a listed as an endangered species in both Canada and the United St ...

'' - Snuffbox

Conservation status

Golden riffleshell mussels ready for release

This entire genus is imperiled. In this genus, 15 species or subspecies are believed to be extinct. Of those remaining, all are federally protected species in the United States. The last to be listed as a federally endangered species was ''

'', which was listed in 2012. This group of freshwater mussels is threatened primarily by habitat alteration as are other freshwater mussels. Dams, erosion, and pollution appear to be the primarily threats. Some workers recognize additional species not currently on the official list of recognized species.

Gallery

Image:Epioblasma capsaeformis.jpg, ''

'' Image:Epioblasma triquetra.jpg, ''

'' Image:Epioblasma walkeri.jpg, '' Epioblasma walkeri''

References

{{Authority control Bivalve genera Taxa named by Constantine Samuel Rafinesque Taxonomy articles created by Polbot