Epioblasma biemarginata (I. Lea, 1857)
Angled riffleshell
Taxonomy & Nomenclature
Synonyms: Unio biemarginatus I. Lea, 1857 (basionym); Dysnomia (Pilea) biemarginata (I. Lea, 1857); Dysnomia (Torulosa) biemarginata (I. Lea, 1857); Dysnomia biemarginata (I. Lea, 1857); Margaron (Unio) biemarginatus (I. Lea, 1857); Plagiola (Torulosa) biemarginata (I. Lea, 1857); Plagiola biemarginata (I. Lea, 1857); Truncilla (Pilea) biemarginata (I. Lea, 1857); Truncilla biemarginata (I. Lea, 1857)
See Graf & Cummings (2025) for a more complete taxonomic history.
Conservation Status
Extinct (Bogan, 2000b; Régnier et al., 2009; Cowie et al., 2017; Graf & Cummings, 2021, 2025)
Last record: 1970 (Williams et al., 2008)
IUCN RedList status: Extinct
The Angled riffleshell was last seen in 1970 (Williams et al., 2008).
Distribution & Habitat
Alabama, Kentucky & Tennessee, USA
It is known to have occurred historically in three states: Alabama, Kentucky and Tennessee. Bogan (2000) lists Illinois as another state in which this species occurred. However, an extensive review of the literature (NatureServe, 2011) does not mention Illinois as a confirmed location of this species, nor does it even mention Illinois in the entire species account. And Régnier et al. (2009) note that "It should not be listed for Illinois".
Biology & Ecology
Hypodigm
5 specimens are in the Illinois Natural History Survey mollusc [url=http://www.inhs.illinois.edu/animals_plants/mollusk/]collection[/url]:
INHS 17042
INHS 20269
INHS 20270
INHS 20271
INHS 20273
Media
References
Original scientific description:
Lea, I. (1857). Description of six new species of uniones from Alabama. Proceedings of the Academy of Natural Sciences of Philadelphia 9: 83. [after 31 March 1857, before 7 January 1858]
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, Aarthur 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 biemarginata. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.1. (http://www.iucnredlist.org). Downloaded on 17 September 2011.
Bogan, Arthur E. (Mollusc Specialist Group). (2000b). Epioblasma biemarginata. The IUCN Red List of Threatened Species 2000: e.T7864A12858843. https://dx.doi.org/10.2305/IUCN.UK.2000.RLTS.T7864A12858843.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.
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 30 June 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.
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). IUCN Red List of Threatened Animals. IUCN, 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.
Johnson, R. I. (1980). Zoogeography of North American Unionacea (Mollusca: Bivalvia) north of the maximum Pleistocene glaciation. Bulletin of the Museum of Comparative Zoology 149(2): 77-189.
Lea, Isaac. (1866). New Unionidæ, Melanidæ, etc., chiefly of the United States. Journal of the Academy of Natural Sciences 6 [O. 11]: 5-65, pls. 1-21 (Obs. 11: 9-69).
Lea, Isaac. (1870). A Synopsis of the Family of Naïades. Philadelphia: Henry C. Lea. 184 pp.
MolluscaBase eds. (2025). MolluscaBase. Epioblasma biemarginata (I. Lea, 1857). Accessed through: World Register of Marine Species at: https://www.marinespecies.org/aphia.php?p=taxdetails&id=857291 on 2025-06-30
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).
Ortmann, A. E. (1918). The nayades (freshwater mussels) of the Upper Tennessee drainage. 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.
Ortmann, A. E. (1925). The naiad-fauna of the Tennessee River system below Walden Gorge. American Midland Naturalist 9(8): 321-372. https://doi.org/10.2307/2992763
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. (1900). 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. (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.
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: 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
Wright, B. H. (1888). Check List of North American Unionidae and Other Fresh Water Bivalves. Portland, Oregon: Dorne & Cook, Printers. 8 pp. (un paginated).
http://naturalsciences.org/sites/default/files/files/documents/research-collections/Bogan_TN_Endangered_Mollusks.pdf
https://extinctanimals.proboards.com/thread/10376/epioblasma-biemarginata-angled-riffleshell
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