Finerayed pigtoe (Fusconaia cuneolus)
Taxonomy:
View taxonomy in ITISListing Status: Endangered and others listed below
General Information
A medium-sized mussel that can grow up to 2.5 inches in size. It has an ovoid shell; the hinged end of the shell is rounded with a straight front margin. The valves are subtriangular or subromboidal, and moderately full beaks curved forward. The outer shell is a greenish yellow to light brown and is indistinctly patterned with fine rays and growth lines. The inner shell surface is white. The Tennessee and Cumberland River basins historically contained the greatest diversity of freshwater mussels anywhere in the world. Species specific to this area are referred to as "Cumberlandian". The finerayed pigtoe is a Cumberlandian species restricted to the middle and upper Tennessee River system and has always been considered rare (Simpson 1914). It was placed on the federal threatened and endangered species list in 1976 as endangered. There are currently five known populations of finerayed pigtoe one in the North Fork Holston River in Virginia, one each in the Clinch and Powell rivers, both crossing the Virginia-Tennessee state line, one in the Little River in Tennessee, and one in the Paint Rock River in Alabama. The Clinch River population extends into two tributaries in Virgina, Copper Creek and Little River. Initial steps have been taken for it to be reintroduced to the Tennessee River in Alabama and the lower Holston and French Broad rivers, both in Tennessee. All surviving populations continue to be threatened by many of the same factors identified at the time of listing e.g., habitat fragmentation, loss, and alteration resulting from impoundments; operation of hydroelectric dams; mining; wastewater discharges; water withdrawal; competition and displacement by non-native species; and the runoff of silt and other pollutants from ground disturbance activities.The species historical range included Alabama, Tennessee, Virginia. See below for information about where the species is known or believed to occur.
Population detail
The following populations are being monitored: Finerayed pigtoe
» Range Information
Current Range
Current range maps are only shown within the jurisdictional boundaries of the United States of America. The species may also occur outside this region.
Wherever found; Except where listed as Experimental Populations
Listing status: Endangered
- States/US Territories in which this population is known to or is believed to occur: Alabama, Kentucky, Tennessee, Virginia
- US Counties in which this population is known to or is believed to occur: View All
- USFWS Refuges in which this population is known to occur: Fern Cave National Wildlife Refuge
U.S.A. (AL;The free-flowing reach of the Tennessee R. from the base of Wilson Dam downstream to the backwaters of Pickwick Reservoir [about 12 RM (19 km)] and the lower 5 RM [8 km] of all tributaries to this reach in Colbert and Lauderdale Cos., see 17.85(a))
Listing status: Experimental Population, Non-Essential
- States/US Territories in which this population is known to or is believed to occur: Alabama
- US Counties in which this population is known to or is believed to occur: View All
- USFWS Refuges in which this population is known to occur:
U.S.A. (TN - specified portions of the French Broad and Holston Rivers; see 17.85(b)(1))
Listing status: Experimental Population, Non-Essential
- States/US Territories in which this population is known to or is believed to occur: Tennessee
- US Counties in which this population is known to or is believed to occur: View All
- USFWS Refuges in which this population is known to occur:
» Candidate Information
No Candidate information available for this species.
No Candidate Assessments available for this species.
No Candidate Notice of Review Documents currently available for this species.
No Uplisting Documents currently available for this species.
» Federal Register Documents
» Species Status Assessments (SSAs)
No Species Status Assessments (SSA's) are currently available for this species.
» Recovery
- Species with Recovery Documents Data Explorer
- Recovery Priority Number: 5
No Delisting Documents currently available for this species.
» Critical Habitat
No Critical Habitat Documents currently available for this species.
» Conservation Plans
No Conservation Plans currently available for this species.
» Petitions
No Petitions currently available for this species.
» Biological Opinions
To see all FWS Issued Biological Opinions please visit the BO Report.
» Life History
Habitat Requirements
Associated with clean, fast-moving water with relatively stable cobble, gravel, and sand substrates free of siltation. The mussel is usually found buried in the substrate in shallow riffle, ford, and shoal areas but can also occur in deeper runs.
Food Habits
A filter feeder, feeding by straining small organisms and food particles from the water.
Movement / Home Range
The finerayed pigtoe is presently known from several tributaries of the Tennessee River above Muscle Shoals, AL; these include the North Fork Holston, Clinch (including Copper Creek and Little River in Virginia), Powell, Little, and Paint Rock rivers.
Reproductive Strategy
Males produce sperm which are discharged into the water and dispersed by currents. Any downstream female of the same species obtains these sperm during filter feeding. Fertilization of the female's eggs by the sperm occurs within the gills of the female. The fertilized eggs are retained in brood pouches, which are a modified section of the gills, to develop into larvae called glochidia. Once developed the females release the glochidia into the water. The glochidia must attach themselves to an appropriate fish host. After riding around on the fish for several weeks the glochidia will fall off the fish and settle on the bottom of the river or stream. The finerayed pigtoe is a short-term brooder. Short-term brooders breed in the spring and early summer and release glochidia by mid to late summer.
» Other Resources
NatureServe Explorer Species Reports-- NatureServe Explorer is a source for authoritative conservation information on more than 50,000 plants, animals and ecological communtities of the U.S and Canada. NatureServe Explorer provides in-depth information on rare and endangered species, but includes common plants and animals too. NatureServe Explorer is a product of NatureServe in collaboration with the Natural Heritage Network.
ITIS Reports-- ITIS (the Integrated Taxonomic Information System) is a source for authoritative taxonomic information on plants, animals, fungi, and microbes of North America and the world.
FWS Digital Media Library -- The U.S. Fish and Wildlife Service's National Digital Library is a searchable collection of selected images, historical artifacts, audio clips, publications, and video." +