North Carolina Wildlife Resources Commission

Atlantic Pigtoe (Conrad, 1834)

Scientific Name: Fusconaia masoni

Classification:  State Endangered

Photo Credit: NCWRC
   

Interior

 

Exterior 

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

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.

 

Shell Anatomy

 
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.

 


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.
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).

 

General Life History For Mussels