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Mississippi National River and Recreation AreaThe historic Stone Arch Bridge across the Mississippi River.
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Mississippi National River and Recreation Area
Sheepnose
(Plethobasus cyphyus) Rafinesque, 1820
A sheepnoe mussel
K.S. Cummings, Illinois Natural History Survey
Other Common Names:
Bullhead.
Habitat:
Medium to large rivers in gravel or mixed sand and gravel.
Length:
Up to 5 inches (12.7 cm).
Outer Shell Color:
Yellow to light brown in young mussels, dark brown for older mussels.
Inner Shell Color:
White, with a slight pink or salmon-colored tint.
Shell Thickness:
Heavy.
Shell Outline:
Slightly longer than wide, and somewhat oval-shaped.
Shell Surface:
Many low, wide bumps run in a single file line down the outer shell surface, from the beak (the swelling above the point where the two shell halves join) to the opposite shell edge. The rest of the shell surface is smooth (without bumps), and looks slightly pressed-in from the beak to the shell edge (similar to the pressed-in mark the length of your finger would make on wet clay), parallel to the row of bumps. Young mussels may have two raised ridges (one on either side of the pressed-in mark).
Scientific Description:
Heavy, brown shell with several radial knobs (running down the center)on disc. If knobs are not pronounced, shell may resemble Higgins’ Eye. Incurrent papillae aborescent.
Similar Looking Mussels:
Host Fish:
Sauger.
Distribution:
Rare throughout its range.
Minnesota State Listing:
Endangered.
Federal Listing:
None.
The mississippi river at night.  

Did You Know?
According to the Environmental Protection Agency, more than 50 cities rely on the Mississippi River for daily water supply.

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Last Updated: May 05, 2008 at 11:43 EST