Plethobasus cooperianus
Photo: Wikimedia Commons (CC) via https://en.wikipedia.org/wiki/Plethobasus_cooperianus
Overview
Plethobasus cooperianus, the orange-footed pimpleback mussel or orangefoot pimpleback, is a rare species of freshwater mussel in the family Unionidae, the river mussels. This aquatic bivalve mollusk is native to the Tennessee, Cumberland, and lower Ohio Rivers in the United States, where its distribution has declined over 70%.
The Orange-footed Pimpleback faces severe population declines primarily due to dam construction and river channelization that have altered natural flow regimes and sediment transport in the Tennessee and Cumberland river systems. Water pollution from agricultural runoff, industrial discharge, and urban development has degraded water quality, while invasive zebra mussels compete for resources and can smother native mussels. The species' complex reproductive cycle, requiring specific fish hosts for larval development, makes it particularly vulnerable to disruptions in aquatic ecosystems.
Habitat
The Orange-footed Pimpleback inhabits medium to large rivers with stable gravel, sand, and mud substrates in the Tennessee and Cumberland river systems. It prefers areas with moderate to swift currents and requires clean, well-oxygenated water for filter feeding and successful reproduction.
