• Mississippi National River and Recreation Area


    National River & Recreation Area Minnesota


(Quadrula metanevra) Rafinesque, 1820
A Monkeyface mussel
K.S. Cummings, Illinois Natural History Survey
Other Common Names:
Knobbed rock shell.
Medium to large rivers in gravel or mixed sand and gravel.
Up to 4 inches (10.2 cm).
Outer Shell Color:
Green or light to dark Brown. Usually with zig-zag green lines or V-shaped markings (especially young mussels)
Inner Shell Color:
Pearly white, with iridescent coloring on one end.
Shell Thickness:
Shell Outline:
An outline of the entire shell varies in shape: from almost round to nearly, but not perfectly square (imagine a square blown up, like a balloon). There may be an indentation in the shell outline just to one side of a raised ridge on the outer shell surface.
Shell Surface:
Outer surface is rough: many small pimple-like bumps scattered over most of the shell's surface. The bumps may be larger around a single raised ridgeline that runs from the beak (the point near where the two shell halves connect) to the shell edge farthest away from the beak. There may be a tiny flattened extension of the shell where the two shell halves join.
Scientific Description:
Shell brown, usually with zig-zag green lines (especially young mussels); multiple, large tubercles on posterior ridge. Soft parts colorful. Incurrent papillae aborescent.
Similar Looking Mussels:
Host Fish:
Sauger, sunfishes.
Relatively uncommon but may be locally abundant.
Minnesota State Listing:
Federal Listing:

Did You Know?

Headwaters of the Mississippi

The Mississippi River is approximately three feet deep at its headwaters at Lake Itasca and has an average surface speed of 1.2 miles per hour.