Striated Fingernail Clam
The striated fingernail clam is a native Colorado mollusk.
About This Species
Species in genus Sphaerium are considered some of the largest. The stiated fingernail clam is the most common species of Sphaerium in North America.
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Physical Characteristics
The striated fingernail clam is medium to large (for this family), up to 14 mm in length and 7 mm in width. Its shell is oval, quite inflated, and sturdy. The hinge is long and thick and the umbones have no cap. The shell is variable in shape, valve and hinge sculpture, and the umbo is not as pronounced or as centrally placed as in Musculium.
Range
In Colorado this species inhabits the Arkansas, Colorado, Platte, Rio Grande, White, and Yampa River drainages.
Habitat
The striated fingernail clam is found in creeks, rivers and occasionally, in lakes. Striated fingernail clams can be seen on the banks of rivers and creeks in mud/clay substrate under two to three inches of water. It is thought to be tolerant of semi-arid environmental conditions. Larger individuals are more likely to resist fluctuating water levels.
Diet
This filter feeder seems to be well-adapted to many environments. A study in Ohio suggests that as temperature increases, the metabolic rate of this species decreases, resulting in smaller individuals.