(Quadrula quadrula) Rafinesque, 1820
A Mapleleaf Mussel

K.S. Cummings, Illinois Natural History Survey

Other Common Names:
Medium to large rivers and reservoirs with a mud, sand, or gravel bottom.
Up to 4 inches (10.2 cm).
Outer Shell Color:
Varies. For young mussels, the color may be yellowish-green or green with faded rays. Older mussels have no markings, and may be greenish-brown, light brown, or dark brown.
Inner Shell Color:
Pearly white, with some 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).
Shell Surface:
There are two ridges on the outer shell surface, which are made up of many pimple-like bumps. These ridges run from the point where the two shell halves meet to the opposite shell edge. The area between the two ridges is smooth (no pimple-like bumps), and looks slightly pressed-in (it looks similar to the pressed-in mark the length of your finger would make on wet clay).
Scientific Description:
Highly variable shell color, adults brownish, juveniles greenish or yellowish. A V-shaped pattern (or sculpture) of tubercles begins at the shell beak and radiates in two rows down the disc separated by a sulcus.
Similar Looking Mussels:
Host Fish:
Flathead catfish.
Widespread and common.
Minnesota State Listing:
Federal Listing:

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