''Ptychobranchus'' is a

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 Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. The term excludes seawater and brackish water, but it does include non-salty mi ...

mussel Mussel () is the common name used for members of several families of bivalve molluscs, from saltwater and Freshwater bivalve, freshwater habitats. These groups have in common a shell whose outline is elongated and asymmetrical compared with other ...

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 ...

. They are

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

, and are mainly found in the Midwest and southeastern

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

as well as

Ontario Ontario is the southernmost Provinces and territories of Canada, province of Canada. Located in Central Canada, Ontario is the Population of Canada by province and territory, country's most populous province. As of the 2021 Canadian census, it ...

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

. Several members of the genus are considered

endangered species An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching, inv ...

. The genus is characterized by folded gills of the female that accommodate larvae packages, thus the meaning of the genus name, "folded gills". She produces one conglutinate in each demibranch of the gills. Members of this genus are long-term brooders and hold their eggs over winter. Species of this genus package their

larva A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...

e, known as

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 ...

, in conglutinates that resemble prey items such as aquatic insects,

fish fry A fish fry is a social event containing battered or breaded fried fish. It usually also includes french fries, coleslaw, macaroni salad, lemon slices, tartar sauce, hot sauce, malt vinegar and dessert. Some Native American versions are cooked ...

, or fish eggs. The lures are intended to attract fish that the glochidia can use as hosts during development. When squeezed, the conglutinate will rupture, allowing the larvae to parasitically attach to the fish.Zanatta, D. T. and R. W. Murphy. (2006)
Evolution of active host-attraction strategies in the freshwater mussel tribe Lampsilini (Bivalvia: Unionidae).
''Molecular Phylogenetics and Evolution'' 41(1), 195-208. Species include:''Ptychobranchus''.
Integrated Taxonomic Information System (ITIS). * ''

Ptychobranchus fasciolaris ''Ptychobranchus fasciolaris'' is a species of freshwater bivalve, freshwater mussel in the family Unionidae, the river mussels. Its common name is kidneyshell. Distribution and conservation status This species is native to eastern North Ameri ...

'' – kidneyshell * '' Ptychobranchus foremanianus'' – rayed kidneyshell * '' Ptychobranchus greenii'' – triangular kidneyshell * '' Ptychobranchus jonesi'' – southern kidneyshell * '' Ptychobranchus occidentalis'' – Ouachita kidneyshell * '' Ptychobranchus subtentum'' – fluted kidneyshell

References

Bivalve genera Taxonomy articles created by Polbot {{Unionidae-stub