Medionidus walkeri (Wright, 1897)

Suwannee moccasinshell

Taxonomy & Nomenclature

Conservation Status

Last record: 1994 (Cummings & Cordeiro, 2012); 1996 (Johnson et al., 2016)

Rediscovered in: 2012 (Johnson et al., 2016)

IUCN RedList status: Critically Endangered

Distribution & Habitat

Suwannee River basin, USA (southeastern)

Biology & Ecology

Hypodigm

Media

References

Original scientific description:

Wright, B. H. (1897). A new plicate Unio. The Nautilus 11(8): 91-92.

Other references:

Burch, J. B. (1975). Freshwater unionacean clams (Mollusca: Pelecypoda) of North America. Malacological Publications: Hamburg, Michigan. 204 pp.

Clench, W. J. and Turner, R. D. (1956). Freshwater mollusks of Alabama, Georgia, and Florida from the Escambia to the Suwannee River. Bulletin of the Florida State Museum, Biological Sciences 1: 97-239.

Cummings, Kevin S. and Cordeiro, J. (2012). Medionidus walkeri. The IUCN Red List of Threatened Species 2012: e.T12930A510583. https://dx.doi.org/10.2305/IUCN.UK.2012-1.RLTS.T12930A510583.en. Downloaded on 14 November 2016.

Deyrup, M. and Franz, R. (1994). Rare and Endangered Biota of Florida, Volume IV: Invertebrates. University Press of Florida, Gainesville, Florida, USA.

Frierson, L. S. (1927). A Classified and Annotated Checklist of the North American Niades. Waco, Texas: Baylor University Press. 111 pp.

Graf, Daniel L. and Cummings, Kevin S. (2021). A ‘big data’ approach to global freshwater mussel diversity (Bivalvia: Unionoida), with an updated checklist of genera and species. Journal of Molluscan Studies 87(1): eyaa034 (36 pp.). https://doi.org/10.1093/mollus/eyaa034

Graf, Daniel L. and Cummings, Kevin S. (2025). The Freshwater Mussels (Unionoida) of the World (and other less consequential bivalves). MUSSEL Project Web Site, https://www.mussel-project.net/. Accessed 5 July 2025.

Haag, Wendell R. (2009). Past and future patterns of freshwater mussel extinctions in North America during the Holocene, pp. 107-128. In: Turvey, Samuel T. (ed.). Holocene Extinctions. Oxford, UK & New York, USA: Oxford University Press. xii + 352 pp.

Heard, W. H. (1979). Identification Manual of the Freshwater Clams of Florida. State of Florida Department of Environmental Regulation.

Hopper, G. W., Bucholz, J. R., DuBose, T. P., Fogelman, K. J., Keogh, S. M. et al. (2023). A trait dataset for freshwater mussels of the United States of America. Scientific Data 10: 745 (pp. 1-15). https://doi.org/10.1038/s41597-023-02635-9

Johnson, Nathan A., Mcleod, John M., Holcomb, Jordan, Rowe, Matthew and Williams, James D. (2016). Early life history and spatiotemporal changes in distribution of the rediscovered Suwannee moccasinshell Medionidus walkeri (Bivalvia: Unionidae). Endangered Species Research 31: 163-175.

Johnson, T. R. (1977). The Amphibians of Missouri. Univ. Kansas Mus. Nat. Hist., Pub. Ed. Ser. 6, Kansas.

MolluscaBase eds. (2025). MolluscaBase. Medionidus walkeri (B. H. Wright, 1897). Accessed through: World Register of Marine Species at: https://www.marinespecies.org/aphia.php?p=taxdetails&id=857345 on 2025-07-05

Simpson, Charles Torrey. (1900a). Synopsis of the naiades, or pearly fresh-water mussels. Proceedings of the United States National Museum 22(1205): 501-1044, pl. 18.

Simpson, Charles Torrey. (1900b). New and unfigured Unionidae. Proceedings of the Academy of Natural Sciences of Philadelphia 52: 74-86.

Simpson, Charles Torrey. (1914). A descriptive catalogue of the naiades, or pearly fresh-water mussels. Parts I-III. Detroit, Michigan: Bryant Walker. 1540 pp.

Williams, James D., Bogan, Arthur E., Butler, Robert S., Cummings, Kevin S., Garner, Jeffrey T., Harris, John L., Johnson, Nathan A. and Watters, G. Thomas. (2017). A revised list of the freshwater mussels (Mollusca: Bivalvia: Unionida) of the United States and Canada. Freshwater Mollusk Biology and Conservation 20: 33-58.

Williams, James D., Butler, R. S., Warren, G. L. and Johnson, N. A. (2014). Freshwater Mussels of Florida. Tuscaloosa, AL: University of Alabama Press. 498 pp.

https://extinctanimals.proboards.com/thread/21670/medionidus-walkeri

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