(Elliptio dilatata) Rafinesque, 1820
A Spike mussel

K.S. Cummings, Illinois Natural History Survey

Other Common Names:
Small to large streams and occasionally lakes in mud or gravel.
Up to 5 inches (12.7 cm).
Outer Shell Color:
Dark brown or black. Young mussels are greenish brown with faint green rays.
Inner Shell Color:
Purple. Sometimes pink or white.
Shell Thickness:
Thick. Moderately heavy.
Shell Outline:
Much longer than wide. The end of the shell farthest from the beak (the slight swelling near the point where the two shell halves join) comes to a slightly rounded point. The end of the shell nearest the beak is rounded. The longest shell edge opposite the beak may be straight or slightly curved in.
Shell Surface:
The outer shell surface is smooth. The entire outer surface may look flattened or slightly bulged out. Running your finger along the highest point of the shell surface that runs from the beak to the farthest shell edge, you may feel a low ridge that curves downward.
Scientific Description:
Moderately heavy, brown or black shell. Inflated and elongate. Posterior end pointed, sometimes bowed. Posterior ridge usually rounded. Posterior slope sometimes with low ridges. Simple postbasal mantle margin. Homogeneous marsupium. Excurrent aperture subdivided. Simple incurrent papillae. Sexes alike.
Similar Looking Mussels:
Spectaclecase; Elephant Ear; Blank Sandshell; Western Pondmussel.
Host Fish:
Gizzard Shad, Yellow Perch, White Crappie, Black Crappie, Flathead Catfish, Sauger
Widespread but sporadic in distribution.
Minnesota State Listing:
Special Concern.
Federal Listing:

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