Giant Floater Anodonta grandis


Federal Status: Not listed (Watters 1995)

Ohio Status: Not listed (Watters 1995)

Key characteristics: Large, thin, elongate shell, beaks elevated above hinge, double-looped beak sculpture, without teeth (Cummings, Mayer 1992).

Similar species: Flat floater, paper pondshell, squawfoot, cylindrical papershell (Cummings, Mayer 1992).

Description: Shell extremely variable but usually large, somewhat elliptical or elongate, and inflated. Shell extremely thin in young mussels, somewhat thicker in older individuals. Anterior end broadly rounded, posterior end bluntly pointed. Ventral margin straight or slightly curved. Umbos full, usually located in the anterior third of the shell but occasionally more toward the center in the large-river form (P. grandis var. corpulenta), elevated above the hinge line. Beak sculpture of three to five double-looped ridges. Shell smooth, light yellow or yellowish green with rays visible in younger specimens, becoming dark green to brown in older shells. Length to 10 inches (25.4 cm) (Cummings, Mayer 1992).

Valves without teeth, hinge line slightly thickened and curved. Beak cavity broad and shallow. Nacre variable and may be silvery white, cream, pink, salmon, or copper-colored (Cummings, Mayer 1992).

Hosts: Thirty-seven hosts have been reported from this species (Watters 1995).

Habitat: Typically, ponds, lakes, and sluggish mud-bottomed pools of creeks and rivers; can be found in a variety of other habitats as well (Cummings, Mayer 1992).


Return to the Species List

Return to the Introduction of Freshwater Mussels

Return to the Biology Home Page

Return to the Marietta College Home Page