# Gonidea

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Genus of bivalves

Gonidea Mature western ridged mussel Conservation status Vulnerable (IUCN 3.1)[1] Vulnerable (NatureServe)[2] Scientific classification Kingdom: Animalia Phylum: Mollusca Class: Bivalvia Order: Unionida Family: Unionidae Genus: Gonidea Conrad, 1857 Species: G. angulata Binomial name Gonidea angulata (Lea, 1838)[3]

***Gonidea angulata***, the **western ridged mussel** or **Rocky Mountain ridged mussel**, is a [species](/source/Species) of [freshwater mussel](/source/Freshwater_mussel), an [aquatic](/source/Aquatic_animal) [bivalve](/source/Bivalve) [mollusk](/source/Mollusk) in the family [Unionidae](/source/Unionidae), the river mussels. It is the only species in the genus ***Gonidea***.

## Description

Shell is 125 mm long, 65 mm high, 40 mm wide.[4]

## Distribution

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.

## Conservation status

The western ridged mussel has declined significantly throughout much of its range in western [North America](/source/North_America). Research indicates that the species has experienced a significant reduction in range from the historic distribution (43%),[5] 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.

In Canada, it lives in [British Columbia](/source/British_Columbia), where the [Committee on the Status of Endangered Wildlife in Canada](/source/Committee_on_the_Status_of_Endangered_Wildlife_in_Canada) (COSEWIC) has listed it as a species of special concern. The Canadian [Species at Risk Act](/source/Species_at_Risk_Act) listed it in the [List of Wildlife Species at Risk](/source/List_of_Wildlife_Species_at_Risk) as being a species of special concern in Canada in 2003, and as endangered in 2010.[6][7]

## References

1. **[^](#cite_ref-IUCN_1-0)** Blevins, E.; Jepsen, S.; Brim Box, J.; Nez, D. (2017) [errata version of 2016 assessment]. ["*Gonidea angulata*"](https://www.iucnredlist.org/species/173073/114146359). *[IUCN Red List of Threatened Species](/source/IUCN_Red_List)*. **2016** e.T173073A114146359. [doi](/source/Doi_(identifier)):[10.2305/IUCN.UK.2016-3.RLTS.T173073A62905403.en](https://doi.org/10.2305%2FIUCN.UK.2016-3.RLTS.T173073A62905403.en). Retrieved 9 January 2026.

1. **[^](#cite_ref-ns_2-0)** [NatureServe](/source/NatureServe). ["*Gonidea angulata*"](https://explorer.natureserve.org/Taxon/ELEMENT_GLOBAL.2.109629/). *NatureServe Explorer*. Arlington, Virginia. Retrieved 2016-07-08.

1. **[^](#cite_ref-3)** Lea, I. 1838. Description of new freshwater and land shells. American Philosophical Society, Transactions 6: 1-111.

1. **[^](#cite_ref-4)** COSEWIC 2003. COSEWIC assessment and status report on the Rocky mountain ridged mussel *Gonidea angulata* in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. vi + 29 pp. (www.sararegistry.gc.ca/status/status_e.cfm) [http://www.sararegistry.gc.ca/virtual_sara/files/cosewic/sr_rocky_mount_ridged_mussel_e.pdf](http://www.sararegistry.gc.ca/virtual_sara/files/cosewic/sr_rocky_mount_ridged_mussel_e.pdf)

1. **[^](#cite_ref-5)** 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.

1. **[^](#cite_ref-6)** COSEWIC. 2005. [Canadian Species at Risk](http://www.sararegistry.gc.ca/virtual_sara/files/species/clwsa%5F0505%5Fe%2Epdf). Committee on the Status of Endangered Wildlife in Canada. 64 pp., page 27.

1. **[^](#cite_ref-7)** COSEWIC. 2011. [\[1\]](http://www.cosewic.gc.ca/eng/sct1/searchdetail_e.cfm?id=791&StartRow=171&boxStatus=All&boxTaxonomic=All&location=1&change=All&board=All&commonName=&scienceName=&returnFlag=0&Page=18) [Archived](https://web.archive.org/web/20110930014121/http://www.cosewic.gc.ca/eng/sct1/searchdetail_e.cfm?id=791&StartRow=171&boxStatus=All&boxTaxonomic=All&location=1&change=All&board=All&commonName=&scienceName=&returnFlag=0&Page=18) 2011-09-30 at the [Wayback Machine](/source/Wayback_Machine). COSEWIC, Committee on the Status of Endangered Wildlife in Canada

Taxon identifiers Gonidea Wikidata: Q31185012 BOLD: 5184 CoL: 7P43K GBIF: 2287882 iNaturalist: 172055 IRMNG: 1417926 ITIS: 80032 NCBI: 55838 Open Tree of Life: 376872 WoRMS: 856857 Gonidea angulata Wikidata: Q3012753 BOLD: 32523 CoL: 3GVSV EoL: 450588 GBIF: 2287883 iNaturalist: 210618 IRMNG: 10238401 ITIS: 80033 IUCN: 173073 NatureServe: 2.109629 NCBI: 55839 Open Tree of Life: 376873 WoRMS: 857315

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Adapted from the Wikipedia article [Gonidea](https://en.wikipedia.org/wiki/Gonidea) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Gonidea?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.