Overview
The western fanshell (Cyprogenia aberti) is a freshwater mussel. The western fanshell is currently found in the Lower Mississippi-St. Francis, Neosho-Verdigris and Upper White River basins, in Arkansas, Kansas, Missouri and Oklahoma. It is considered extirpated from the Lower Arkansas basin.
This species is typically found in large creeks and rivers with good water quality, moderate to swift current and gravel-sand substrates. Like all mussels, the western fanshell is an omnivore that primarily filter feeds on a wide variety of microscopic particulate matter suspended in the water column, including phytoplankton, zooplankton, bacteria, detritus and dissolved organic matter.
As with most freshwater mussels, western fanshells have a unique life cycle that relies on fish hosts for successful reproduction. Larval-stage mussels, called glochidia, attach themselves to host fish. Logperch, slenderhead darter, fantail darter and rainbow darter serve as host fish for the western fanshell.
Scientific Name
Identification Numbers
Characteristics
Food
Like all mussels, western fanshell are omnivores that primarily filter feed on a wide variety of microscopic particulate matter suspended in the water column, including phytoplankton, zooplankton, bacteria, detritus and dissolved organic matter. Juveniles likely pedal feed in the sediment, whereas adults filter feed from the water column.
Physical Characteristics
Western Fanshell have a thick, compressed to moderately inflated, round to triangular shell (up to 3 inches (76 millimeters)).
Western fanshell periostracum is a dull tan with a distinctive ray pattern from bands of tiny pigment flecks. The shell has a wrinkled or rough appearance.
Life Cycle
The life cycle of western fanshell, like most freshwater mussels, is complex, relying on host fish for successful reproduction. Male mussels release their sperm into the water column where it is siphoned in by females. Once fertilization has taken place in the gills of the female mussel, mature microscopic glochidia, or larva, are released by the females where they must attach themselves to the gills, and or, fins of fish hosts to continue developing. Western fanshell are bradyticitc, meaning long-term, brooders that typically spawn from August to October and usually release their larvae in early spring.
Each mussel species has specific fish species, also called the host fish, that are needed by the glochidia to keep growing to ultimately transform into juveniles. After a few weeks of living as parasites, they drop off and land on the river bottom where they grow into adults. Western fanshell host fish include the logperch (Percina caprodes), slenderhead darter (Percina phoxocephala), fantail darter (Etheostoma flabellare), orangebelly darter (Etheostoma radiosum) and rainbow darter (Etheostoma caeruleum).
Habitat
Western fanshell typically prefer large creeks and rivers with good water quality, moderate to swift current and gravel-sand substrate.
A natural body of running water.
Timeline
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