AIM

Pyganodon grandis (Say)


Giant floater

Recognition

Easily recognized among our species by the toothless hinge. The shell can be light to dark colored and it is usually very fragile. The nacre is white. The usual size is 110 to 160 mm.

Summary

This species was Anodonta grandis Say until recently. Many fish species are known to serve as hosts for this species. All of these are warmer water species and most of them were introduced into Montana. The known native hosts are the freshwater drum, Iowa darter, brook stickleback and possibly channel catfish. This species likely expanded in Montana with the introduction and range expansion of more of its host fish. These include carp, bullheads, golden shiner, centrarchids and yellow perch.

Distribution

In the prairie rivers and in intermittent streams if deep permanent pools are present. Outside of Montana it is widespread east of the divide. It is also covered in the Field Guide to the Freshwater Mussels of the Midwest.

17 DEC 1995 updated on 12 JAN 1996 D.L. Gustafson
AIM home page
dlg@rivers.oscs.montana.edu