The Alabama moccasinshell (Medionidus acutissimus) is a species of freshwater mussel in the family Unionidae, the river mussels. It is native to Alabama, Mississippi, Georgia, Tennessee, and possibly Florida. It is a federally listed threatened species of the United States. This aquatic bivalve mollusk is about 3 centimeters long with a thin yellow or brownish yellow shell. The nacre is mostly translucent with a salmon pink area.