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Note: Red text
is defined in the Glossary
Description
Isaac Lea described the mountain creekshell in 1838. There is
sexual dimorphism in shell shape. The ventral
margin is curved in the male. In the female, the ventral
margin is straight with a distinct swelling along the posterio-ventral
margin to accommodate the marsupium.
Older females may have a constriction along the posterio-ventral
margin associated with this swelling. The dorsal
margin may be slightly curved. There are two short pseudocardinal
teeth in the left valve, and
one in the right. The lateral teeth
are thin and slightly curved, following the dorsal margin. The periostracum
may be olive or golden brown to black. If present, rays
are narrow and indistinct. The nacre
may range from purples to copper in color. (Parmalee and Bogan 1998).
Distribution
(see map)
The mountain creekshell is often found in sand/gravel substrates
often associated with beds of water willow, Justicia americana,
generally in smaller streams (Parmalee and Bogan 1998). In North
Carolina, it is only known from the Hiwassee River where overall
habitats are dominated by coarser substrates. NOTE: All headwater
areas that flow into these occupied habitats should receive special
management.
Habitat Preferences
This species is found in silts and sands in areas with limited
currents such as in lakes, ponds, and protected areas of rivers
and creeks (Johnson 1970). Bill Adams and Andy Gerberich (personal
communication) found this species in a course sand substrate with
significant amounts of fine organic matter. Also in the area were
occasional patches of fragrant waterlily (Nympaea odorata)
and spatterdock (Nuphar luteum).
Life History
This species is bradytictic; females
may be gravid from September to May
(Parmalee and Bogan 1998, Ortmann 1921). Several species of sculpin
(banded, black, mottled, and slimy) have been identified as fish
hosts (Watters 1994).
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