• Mississippi National River and Recreation Area

    Mississippi

    National River & Recreation Area Minnesota

Butterfly

(Ellipsaria lineolata) Rafinesque, 1820
A Butterfly mussel
U.S. Army Corps of Engineers
Other Common Names:
None.
Habitat:
Butterflies prefer large rivers and are often embedded in sand or gravel.
Length:
Can be up to 4 inches (10.2 cm).
Outer Shell Color:
Varies between yellow and brown. Some shells may have rays that are V-shape or irregular rectangular blotches. Older shells will have faint rays or no rays at all.
Inner Shell Color:
White, may be of rainbow color toward the end farthest from the area where the two halves meet.
Shell Thickness:
Thick and solid.
Shell Outline:
An outline of the entire shell is somewhat triangular (imagine an equal-sided triangle blown up, like a balloon). The end closest to where the two halves meet is rounded from top to bottom. The opposite end is somewhat pointed. The raised part of the top of the shell where the two halves meet is squeezed together and pointed towards the closest end. This part is located below the elastic part of the shell that holds the two halves together.
Shell Surface:
Smooth.
Scientific Description:
Yellow or brown shell with interrupted greenish rays comprised of V-shaped marks. Very sharp posterior ridge, and narrow posterior slope. Male compressed; female inflated.
Similar Looking Mussels:
Pigtoe and Deertoe.
Host Fish:
Freshwater Drum (Sheephead), Green Sunfish
Distribution:
Widespread but only locally abundant. Disappearing from many areas where it formerly occurred.
Minnesota State Listing:
Threatened.
Federal Listing:
None.

Did You Know?

Itasca, Headwaters of the Mississippi River

The river is so shallow at Lake Itasca that children can walk across the Mississippi. Between Governor Nicholls Wharf and Algiers Point in New Orleans, the Mississippi is more than 200 feet deep.