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Note: Red text
is defined in the Glossary
Description
Roanoke slabshells grow to greater than 150 mm total length. In
North Carolina, it is one of our largest freshwater mussels species.
The posterior ridge varies from being
well defined to being uniformly rounded. The periostracum
is generally smooth except near the margins
of the shell. Growth
rests are distinct. The color of the periostracum is usually
a yellow-reddish-brown that darkens with age. Narrow greenish
rays are often present from the anterior
end of the shell to the posterior ridge.
The rays are less distinct in larger individuals. The nacre
is usually iridescent. Three distinctive characteristics of this
species are the presence of small folds (plications)
centrally located on the periostracum of most individuals, certain
of the incurrent papillae being subdivided
into smaller papillae, and irregularly developed branchial
septa.
Distribution
(see map)
The Roanoke slabshell ranges from at least the Roanoke River
in North Carolina to the Savannah River in Georgia and South Carolina.
Walter (1954) considered the range from the Connecticut River to
the Altamaha River.
Distribution by
County: Pee Dee River Basin: Montgomery County (Uwharrie River Subbasin),
Richmond County (Pee Dee River). Cape Fear River Basin: Cumberland
Co. (Cape Fear River); Harnett Co. (Cape Fear River). Neuse River
Basin: Wake Co. (Middle Cr.), Johnston Co. (Neuse River, Mill Cr.
Subbasin, and Swift Cr. Subbasin). Tar River Basin: Nash Co. (Tar
River, Swift and Fishing creek subbasins), Edgecombe Co. (Tar R.,
Swift and Fishing creek subbasins), Halifax Co. (Fishing Cr. Subbasin).
Roanoke River Basin: Halifax Co. (Roanoke River); Northampton Co.
(Roanoke River). NOTE: All headwater areas that flow into these
occupied habitats should receive special management.
Habitat Preferences
In the Tar River, the Roanoke slabshell is usually found associated
with the deeper channels near shore in relatively fast flowing water.
The substrate consists of coarse to medium sized sands and small
gravel. The species is also associated with coarser substrates,
such as a mix of gravel and cobble seen in the Cape Fear River in
Harnett County.
Life History
Little is known of the life history of this species. However,
gravid females are found as early as
March. In general, the best populations exist in rivers and creeks
downstream from the last major dams within the river basins. This
suggests that dominant fish hosts are
anadromous.
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