''Epioblasma'' 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
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 ...
s,
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 ...
, 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 use the gills, fins, or skin of a host fish for nutrients during the larval glochidia 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). It is one of the modern descendan ...
" symbol are extinct due to human activity
*Subgenus †''Epioblasma''
**†''
Epioblasma flexuosa'' - 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 ...
'' - Cumberland leafshell
*Subgenus ''Pilea''
**†''
Epioblasma haysiana'' - Acornshell
**''
Epioblasma obliquata''
***''Epioblasma obliquata obliquata'' - Purple catspaw
***''Epioblasma obliquata perobliqua'' - White catspaw
**†''
Epioblasma personata
''Epioblasma personata'', the round combshell or fine-rayed pearly mussel, is an extinct species of freshwater mussel in the family Unionidae. It was endemic to the drainages of the Tennessee River and Ohio River in the United States
...
'' - Round combshell
*Subgenus ''Plagiola''
**†''
Epioblasma arcaeformis
''Epioblasma arcaeformis'', the sugarspoon or arc-form pearly mussel, was a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels. No live individuals have been observed since the early 20th centur ...
'' - Sugarspoon
**''
Epioblasma brevidens
The Cumberlandian Combshell (''Epioblasma brevidens'') 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. Thi ...
'' - Cumberlandian combshell
**†''
Epioblasma lenior'' - Narrow catspaw
**''
Epioblasma metastriata'' - Upland combshell
**''
Epioblasma othcaloogensis'' - Southern acornshell
**''
Epioblasma penita
''Epioblasma penita'', the southern combshell or penitent mussel, is a species of freshwater mussel, an aquatic animal, aquatic bivalve mollusk in the family Unionidae, the river mussels.
This species is Endemism, endemic to the United States. ...
'' - Southern combshell
*Subgenus ''Torulosa''
**''
Epioblasma ahlstedti'' - Duck River oyster mussel
**†''
Epioblasma biemarginata'' - Angled riffleshell
**''
Epioblasma capsaeformis'' - Oyster mussel
**†''
Epioblasma cincinnatiensis'' - Cincinnati Riffleshell
**''
Epioblasma florentina''
***''
Epioblasma florentina aureola'' - Golden riffleshell
***''
Epioblasma florentina curtisii'' - Curtis pearlymussel
***†''
Epioblasma florentina florentina'' - Yellow blossom
***''
Epioblasma florentina walkeri'' - Tan riffleshell
**†''
Epioblasma propinqua'' - 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
''Epioblasma turgidula'', the turgid blossom pearly mussel, turgid riffle shell, turgid-blossom naiad or turgid blossom, was a species of freshwater mussel, a mollusk in the family Unionidae. The US Fish and Wildlife Service declared the spe ...
'' - Turgid riffle shell
*Subgenus ''Truncillopsis''
**''
Epioblasma triquetra'' - Snuffbox
Conservation status

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. The last to be listed as a federally endangered species was ''
Epioblasma triquetra'', 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, '' Epioblasma capsaeformis''
Image:Epioblasma triquetra.jpg, '' Epioblasma triquetra''
Image:Epioblasma walkeri.jpg, ''Epioblasma 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 ...
''
References
{{Taxonbar, from=Q3015342
Bivalve genera
Taxa named by Constantine Samuel Rafinesque
Taxonomy articles created by Polbot