Hagerman Fossil Beds National Monument - Mollusks

The Hagerman area has five species of freshwater snails that are listed as threatened or endangered under the Endangered Species Act: the Snake River Physa (Physa natricaria ), the Lanx ( Lanx sp .)the Bliss Rapids snail (Taylorconcha serpenticola ), the Utah valvata ( Valvata utahensis ), and the Idaho springsnail ( Pyrgulopsis idahoensis ). The decline of the aquatic mollusk species has been primarily attributed to changes in the river from free-flowing, cold water to impounded, slower, warmer habitats. Another variable is the population increase of non-native invasive aquatic species such as the New Zealand mudsnail ( Potamopyrus antipodarum ).