Fusconaia subrotunda

Fusconaia subrotunda, the longsolid, long solid mussel or long solid naiad, is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae.

This mussel, sometimes called a pigtoe, is found in river gravel. Young mussels are light brown, but darken to nearly black with age.

This species is found in Canada and the United States.

Subspecies

 * Fusconaia subrotunda kirklandiana
 * Fusconaia subrotunda lesueriana Lea
 * Fusconaia subrotunda pilaris Lea
 * Fusconaia subrotunda subrotunda