Epioblasma lewisii (Walker, 1910)
Forkshell, Lewis’ pearly mussel
Taxonomy & Nomenclature
Synonyms: Truncilla lewisii B. Walker, 1910; Truncilla (Dysnomia) lewisii (B. Walker, 1910); Dysnomia lewisii (B. Walker, 1910); Plagiola lewisi Walker, 1910
See Graf & Cummings (2025) for a more complete taxonomic history.
Conservation Status
Extinct (Bogan, 2000b; NatureServe, 2014, 2025; Graf & Cummings, 2021, 2025)
Last record: pre-1959 (NatureServe, 2014)
IUCN RedList status: Extinct
Distribution & Habitat
Alabama, Kentucky & Tennessee, USA
Biology & Ecology
Hypodigm
Only 1 specimen with soft tissue was ever collected, and is housed in the National Museum of Natural History, Leiden, The Netherlands (NatureServe, 2011).
1 specimen is in the Illinois Natural History Survey mollusc [url=http://www.inhs.illinois.edu/animals_plants/mollusk/]collection[/url]:
INHS 20278
Media
References
Original scientific description:
Walker, B. (1910). Description of a new species of Truncilla. The Nautilus. 24(4): 42-44, pl. 3, figs. 3-5.
Other references:
Baillie, J. and Groombridge, B. (eds). (1996). 1996 IUCN Red List of Threatened Animals. pp. 378. International Union for Conservation of Nature, Gland, Switzerland and Cambridge, UK.
Bogan, Arthur E. (1993). Freshwater bivalve extinctions (Mollusca: Unionoida): A search for causes. American Zoologist 33(6): 599-609. https://doi.org/10.1093/icb/33.6.599
Bogan, Arthur E. (2000a). Epioblasma lewisii. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. (http://www.iucnredlist.org). Downloaded on 22 April 2012.
Bogan, Arthur E. (Mollusc Specialist Group). (2000b). Epioblasma lewisii. The IUCN Red List of Threatened Species 2000: e.T7892A12862418. https://dx.doi.org/10.2305/IUCN.UK.2000.RLTS.T7892A12862418.en. Accessed on 19 June 2022.
Bogan, Arthur E. and Parmalee, Paul W. (1983). Tennessee's Rare Wildlife. Volume II: The Mollusks. Tennessee Wildlife Resources Agency.
Burch, J. B. (1975). Freshwater unionacean clams (Mollusca: Pelecypoda) of North America. Malacological Publications: Hamburg, Michigan. 204 pp.
Cicerello, R. R. and Schuster, G. A. (2003). A guide to the freshwater mussels of Kentucky. Kentucky State Nature Preserves Commission Scientific and Technical Series 7: 1-62.
Cowie, Robert H., Régnier, Claire, Fontaine, Benoît, and Bouchet, Philippe. (2017). Measuring the Sixth Extinction: what do mollusks tell us? The Nautilus 131(1): 3-41.
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 2 July 2025.
Groombridge, B. (ed.). (1994). 1994 IUCN Red List of Threatened Animals. IUCN, Gland, Switzerland and Cambridge, UK.
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.
Haag, Wendell R. (2012). North American Freshwater Mussels: Natural History, Ecology, and Conservation. Cambridge and New York: Cambridge University Press. xvi + 505 pp., 21 pls.
Haas, F. (1969). Superfamilia Unionacea. Das Tierreich 88: x, 1-663. Walter de Gruyter & Co., Berlin.
Hilton-Taylor, Craig. (2000). 2000 IUCN Red List of Threatened Species. IUCN, Gland, Switzerland and Cambridge, UK.
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
IUCN. (1990). 1990 IUCN Red List of Threatened Animals. Gland, Switzerland and Cambridge, UK.
Johnson, R. I. (1978). Systematics and zoogeography of Plagiola (= Dysnomia = Epioblasma), an almost extinct genus of freshwater mussels (Bivalvia: Unionidae) from middle North America. Bulletin of the Museum of Comparative Zoology 148: 239-321.
Lewis, J. (1871). On the shells of the Holston River. American Journal of Conchology 6: 216-226.
Lydeard, C., Garner, J. T., Hartfield, P. and Williams, James D. (1999). Freshwater mussels in the Gulf Region: Alabama. Gulf of Mexico Science 17(2): 125-134.
Mirarchi, R. E. (2004). Alabama Wildlife. Volume One: A Checklist of Vertebrates and Selected Invertebrates: Aquatic Mollusks, Fishes, Amphibians, Reptiles, Birds, and Mammals. University of Alabama Press: Tuscaloosa, Alabama. 209 pp.
MolluscaBase eds. (2025). MolluscaBase. Epioblasma lewisii (B. Walker, 1910). Accessed through: World Register of Marine Species at: https://www.marinespecies.org/aphia.php?p=taxdetails&id=857297 on 2025-07-02
NatureServe. (2014). NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available http://explorer.natureserve.org. (Accessed: January 28, 2015).
NatureServe. (2025). Epioblasma lewisii: Forkshell. NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available at: https://explorer.natureserve.org/ [Accessed 2 July 2025]
Ortmann, A. E. (1918). The nayades (freshwater mussels) of the Upper Tennessee drainage. With notes on synonymy and distribution. Proceedings of the American Philosophical Society 57(6): 521-626.
Ortmann, A. E. (1924). The naiad-fauna of Duck River in Tennessee. American Midland Naturalist 9(1): 18-62.
Parmalee, P. W. and Bogan, Arthur E. (1998). The Freshwater Mussels of Tennessee. Knoxville, Tennessee: University of Tennessee Press. 328 pp.
Régnier, Claire, Fontaine, Benoît and Bouchet, Philippe. (2009). Not Knowing, Not Recording, Not Listing: Numerous Unnoticed Mollusk Extinctions. Conservation Biology 23(5): 1214-1221. https://doi.org/10.1111/j.1523-1739.2009.01245.x [Appendix S1-S2]
Simpson, Charles Torrey. (1914). A descriptive catalogue of the naiades, or pearly fresh-water mussels. Parts I-III. Detroit, Michigan: Bryant Walker. 1540 pp.
Stansbery, D. H. (1970). American Malacological Union Symposium: Rare and Endangered Mollusks: 2. Eastern Freshwater Mollusks (I) The Mississippi and St. Lawrence Systems. Malacologia 10(1): 9-22.
Turgeon, D. D., Bogan, A. E., Coan, E. V., Emerson, W. K., Lyons, W. G. et al. (1988). Common and Scientific Names of Aquatic Invertebrates from the United States and Canada: Mollusks. American Fisheries Society Special Publication (16). 277 pp.
Turgeon, D. D., Quinn, J. F., Jr., Bogan, A. E., Coan, E. V., Hochberg, F. G., Lyons, W. G., Mikkelsen, P. M., Neves, R. J., Roper, C. F. E., Rosenberg, G., Roth, B., Scheltema, A., Thompson, F. G., Vecchione, M. and Williams, J. D. (1998). Common and scientific names of aquatic invertebrates from the United States and Canada: Mollusks. 2nd Edition. American Fisheries Society Special Publication 26, Bethesda, Maryland: 526 pp.
Watters, G. Thomas, Hoggarth, Michael A. and Stansbery, David H. (2009). The Freshwater Mussels of Ohio. Columbus, OH: Ohio State University Press. xiv + 421 pp. https://doi.org/10.2307/j.ctv16b77pv
Wells, S. M., Pyle, R. M. and Collins, N. M. (compilers). (1983). The IUCN Invertebrate Red Data Book. IUCN, Gland, Switzerland and Cambridge, UK.
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(2): 33-58. https://doi.org/10.31931/fmbc.v20i2.2017.33-58
Williams, James D., Bogan, Arthur E. and Garner, Jeffrey T. (2008). Freshwater mussels of Alabama and the Mobile Basin in Georgia, Mississippi and Tennessee. Tuscaloosa, Alabama: University of Alabama Press. xv + 908 pp.
Williams, James D., Warren, M. L., Cummings, Kevin S., Harris, J. L. and Neves, R. J. (1993). Conservation status of freshwater mussels of the United States and Canada. Fisheries 18(9): 6-22. https://doi.org/10.1577/1548-8446(1993)018%3C0006:CSOFMO%3E2.0.CO;2
http://naturalsciences.org/sites/default/files/files/documents/research-collections/Bogan_TN_Endangered_Mollusks.pdf
https://extinctanimals.proboards.com/thread/10367/epioblasma-lewisii-forkshell
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