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Note: Red text
is defined in the Glossary
Description
The Atlantic pigtoe was described by Conrad in 1834 from the Savannah
River in Georgia. This species has a medium, sub-rhomboid shaped
shell that rarely exceeds 60 mm in
length. Individuals from headwater streams tend to be more elongate
than those found in larger streams. The posterior
ridge is angular and very distinct. Valves
are usually compressed, but the umbos
extend well above the dorsal margin.
The periostracum generally is yellowish
brown or greenish brown with a parchment-like texture. The nacre
is somewhat shiny and can be white, salmon, orange or iridescent
blue. There are two pseudocardinal
and two lateral teeth
in the left valve and one of each in
the right valve. The anterior
pseudocardinal tooth in the right valve is vestigial.
Distribution
(see map)
The Atlantic pigtoe is a southern Atlantic Slope species that
is found from the Ogeechee River Basin in Georgia north to the James
River Basin in Virginia. Historically, this species occurred in
every Atlantic drainage in North Carolina except the Cooper-Santee
and Waccamaw river basins. The species has declined across its range.
It appears that the Atlantic pigtoe has recently been extirpated
from the Deep River in Moore County, Cape Fear River in Harnett
and Cumberland counties, Black River in Sampson, Bladen, and Pender
counties. NOTE: All headwater areas that flow into these occupied
habitats should receive special management.
Habitat Preferences
The Atlantic pigtoe inhabits mostly medium to large
streams. It prefers clean, swift waters with stable gravel, or sand
and gravel substrate. It often is found at the downstream edge of
riffle areas.
Life History
The Atlantic pigtoe is a tachytictic
breeder (Fuller 1973). Gravid females
have been found from late June through early July. Identified fish
hosts include the bluegill sunfish and shield darter (Watters
and. O'Dee 1997).
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