Gonidea angulata, the western ridged musselorRocky Mountain ridged mussel, is a speciesoffreshwater mussel, an aquaticbivalvemollusk in the family Unionidae, the river mussels. It is the only species in the genus Gonidea.
The western ridged mussel historically occurred in river basins spanning portions of the western states of California, Idaho, Nevada, Oregon, and Washington, and the Canadian province of British Columbia.
The western ridged mussel has declined significantly throughout much of its range in western North America. Research indicates that the species has experienced a significant reduction in range from the historic distribution (43%),[4] with the southern extent of the species’ range in California having contracted northward approximately 475 miles as compared to the historic range. Live western ridged mussels were not detected at 46% of the 87 sites where it historically occurred and that have been recently revisited.
^Blevins, E., S. Jepsen, J. Brim Box, D. Nez, J. Howard, A. Maine, and C. O’Brien. 2017a. Extinction risk of western North American freshwater mussels: Anodonta nuttalliana, the Anodonta oregonensis/kennerlyi clade, Gonidea angulata, and Margaritifera falcata. Freshwater Mollusk Biology and Conservation 20:71–88.
^COSEWIC. 2005. Canadian Species at Risk. Committee on the Status of Endangered Wildlife in Canada. 64 pp., page 27.
^COSEWIC. 2011. [1]Archived 2011-09-30 at the Wayback Machine. COSEWIC, Committee on the Status of Endangered Wildlife in Canada
