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is defined in the Glossary
Description
This species was described by Conrad in 1834 from the Flint River
in Alabama. The Cumberland bean is a small species with solid, elongate,
inflated, oval valves. Female shells
reach a slightly larger size than males, attaining a maximum
length of about 55 mm. Beaks are high
and situated near the anterior end
where the shell is thickest. The periostracum
is somewhat glossy and often appears dark greenish-black in older
specimens. Young specimens may be olive-green or yellowish-brown
with numerous wavy, dark green rays.
The nacre color is a bluish white or
white with a bluish iridescence posteriorly.
The left valve has two solid triangular
pseudocardinal teeth, a narrow interdentum
and two long, straight, relatively heavy lateral
teeth. The right valve has three
pseudocardinal teeth and a single lateral tooth (Parmalee and Bogan
1998).
Distribution (see
map)
Historically, the Cumberland bean was restricted to tributary
streams of the Tennessee and Cumberland rivers and was most abundant
in the Cumberland system. Historic records for the species exist for
the Tennessee River, South Chickamauga Creek, Paint Rock River, Flint
River, Hiwassee River, Clinch River, Cumberland River, Buck Creek,
Obey River, Rockcastle River, Laurel Fork of the Rockcastle River,
and Beaver Creek. Populations of the species still exist in Cumberland
River tributaries in Kentucky and Tennessee, and the Hiwassee River
downstream of Apalachia Dam in Tennessee. This species is thought
to be extirpated from North Carolina.
Habitat Preferences
The Cumberland bean typically inhabits medium-sized streams
to small rivers (5-20m width). It prefers gravel and sand/gravel
substrates in riffle areas with moderate to fast current. This species
frequently occurs in the transition zone between gravel and sand
substrates (Clarke 1981).
Life History
This species is a bradytictic breeder.
Probable fish hosts that have been
identified for the Cumberland bean include the following darter
species: fantail, stripetail, sooty, barcheek, striped and Tennessee
snubnose (Layzer and Anderson 1991, 1992).
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