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Mississippi National River and Recreation Area
Ebonyshell
(Fusconaia ebena) Lea, 1831
Two Black Sandshells
K.S. Cummings, Illinois Natural History Survey
Other Common Names:
Black Shell.
Habitat:
Large rivers in sand and gravel.
Length:
Up to 2.9 inches (7.4cm).
Outer Shell Color:
Black or brown. Has a smooth surface overall: growth rings form slightly raised ridges. No rays.
Inner Shell Color:
Pearly white, with some iridescent coloring on one end.
Shell Thickness:
Thick. Very Heavy.
Shell Outline:
An outline of the entire shell edge is round.
Shell Surface:
From the inside of the shell, there is a large depression that forms a visible bulge on the outer shell surface, which is the beak. The beak is large, rising up over the rest of the shell surface and then curving backward over the point where the 2 shell halves join. The rest of the shell's outer surface is smooth, with no bumps. The surface looks swollen or bulged out.
Scientific Description:
Brown or black, very heavy shell. Beaks prominent and curved toward the anterior margin. Disc, posterior ridge, ventral and postbasal margins – all convexly rounded (bulged outward). Postbasal mantle margin: simple. Marsupium: tetragenous (4-parted). Soft parts: off-white.
Similar Looking Mussels:
Ohio River Pigtoe.
Host Fish:
Skipjack herring, a migratory species restricted from the Upper Miss. River above Pool 20 since the 1913 completion of the Keokuk (Iowa) Dam. Restriction of the movement of this host fish has constricted the range of this mussel.
Distribution:
Histroically widespread and abundant, but rare in much of the Midwest.
Minnesota State Listing:
Endangered.
Federal Listing:
None.
Mississippi River Watershed  

Did You Know?
The Mississippi River Basin, or Watershed drains 41% of the continental United States and includes 31 states and 2 Canadian provinces.

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Last Updated: September 25, 2006 at 09:53 EST