Paper Pondshell (Utterbackia imbecillis) is a large (shell length up to 6.5 cm) freshwater mussel that is distributed through Ontario, Canada and the United States east of the Rocky Mountains. In New Mexico they currently only occur in the lower Canadian River in the Conchas Reservoir (San Miguel County), there has been one sighting in Ute Reservoir (Harding County), and they were introduced to the middle Rio Grande (Sandoval County). They inhabit lakes and rivers where they imbed themselves in mud, sand, and gravel substrates. They are hermaphroditic over much of their range, though some populations do have separate sexes; it is unknown which reproductive strategy the New Mexico population employs.