White Wartyback

Plethobasus cicatricosus, the white warty-back pearly mussel or white wartyback, is a species of freshwater mussel in the family Unionidae, the river mussels. Once widely distributed in the Ohio, Cumberland, and Tennessee River systems in the United States, its range has declined dramatically to the point of near-extinction. It is a federally listed endangered species of the United States.

This mussel is yellow-green or yellow-brown in color. The nacre is white and partly iridescent. There is a row of tubercles on one edge of the shell.