The oval pigtoe (''Pleurobema pyriforme'') is a federally endangered

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 species is

endemic Endemism is the state of a species being found 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 found elsew ...

to 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 ...

in the states of Georgia, Florida, and Alabama . The oval pigtoe was originally described from the

Chattahoochee River The Chattahoochee River forms the southern half of the Alabama and Georgia border, as well as a portion of the Florida - Georgia border. It is a tributary of the Apalachicola River, a relatively short river formed by the confluence of the Chatta ...

near

Columbus, Georgia Columbus is a consolidated city-county located on the west-central border of the U.S. state of Georgia. Columbus lies on the Chattahoochee River directly across from Phenix City, Alabama. It is the county seat of Muscogee County, with which it ...

. Historically, this mussel was very abundant in the

Flint River The Flint River is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map, accessed April 15, 2011 river in the U.S. state of Georgia. The river drains of western Georgia, flowing south from the u ...

in Georgia, the Chattahoochee River in Georgia and

Alabama (We dare defend our rights) , anthem = "Alabama (state song), Alabama" , image_map = Alabama in United States.svg , seat = Montgomery, Alabama, Montgomery , LargestCity = Huntsville, Alabama, Huntsville , LargestCounty = Baldwin County, Al ...

, the

Chipola River The Chipola River is a tributary of the Apalachicola River in western Florida. It is part of the ACF River Basin watershed. The U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map, accessed April 15 ...

in Alabama and

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...

, the

Ochlockonee River The Ochlockonee River ( ) is a fast running river, except where it has been dammed to form Lake Talquin in Florida, originating in Georgia and flowing for before terminating in Florida. Background The name is from the Hitchiti language words ...

in Georgia and Florida, the

Apalachicola River The Apalachicola River is a river, approximately 160 mi (180 km) long in the state of Florida. The river's large watershed, known as the ACF River Basin, drains an area of approximately into the Gulf of Mexico. The distance to its fa ...

and Suwanee/ Santa Fe Rivers in Florida, and

Econfina Creek Econfina Creek is a small river in the middle Florida Panhandle. It flows through hilly country, and has sections of whitewater rapids. Much of its flow comes from springs. The river ends at Deer Point Lake, a reservoir that provides the freshw ...

in Florida. However, the populations in all river systems have declined significantly due to land use changes, development, and the construction of dams.

References

Molluscs of the United States Pleurobema Bivalves described in 1857 ESA endangered species Taxonomy articles created by Polbot {{Unionidae-stub