Mountain Creekshell (Lea, 1838)

Scientific Name: Villosa vanuxemensis

Classification:  State Threatened

Photo Credit: NCWRC
   

Interior

 

Exterior 

NOTE: Hover over the bold words for definitions or see the Glossary.

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).

 

Shell Anatomy

 
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.

 


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).

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).

General Life History For Mussels