Epioblasma haysiana (I. Lea, 1834)

Acorn pearly mussel, Acornshell



Taxonomy & Nomenclature

Synonym/s: Dysnomia haysiana I. Lea, 1834; Plagiola haysiana I. Lea, 1834


Conservation Status

Last record: 1800's (Alabama), 1970's (Cumberland and Tennessee Rivers)

IUCN RedList status: Extinct


The last known population of the Acorn pearly mussel (Epioblasma haysiana) is believed to have been driven extinct by sewage waste contamination of its habitat (Bogan, 2000; NatureServe, 2011).



Alabama, Kentucky, Tennessee and Virginia, USA


Biology & Ecology




8 specimens are in the Illinois Natural History Survey mollusc collection:

INHS 1555
INHS 20279
INHS 20280
INHS 20281
INHS 20282
INHS 20283
INHS 20284
INHS 20285






Bogan, A. E. (2000). Epioblasma haysiana. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. (https://www.iucnredlist.org). Downloaded on 22 April 2012.

Bogan, Arthur E. and Parmalee, Paul W. (1983). Tennessee's Rare Wildlife. Volume II: The Mollusks. Tennessee Wildlife Resources Agency.

Cicerello, R.R. and G.A. Schuster. 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.

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.

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(6): 239-320.

Jones, J.W., R.J. Neves, M.A. Patterson, C.R. Good, and A. DiVittorio. 2001. A status survey of freshwater mussel populations in the upper Clinch River, Tazewell County, Virginia. Banisteria, 17: 20-30.

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.

NatureServe. (2014). NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org. (Accessed: January 29, 2015).

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: 521-626.

Parmalee, P.W. and A.E. Bogan. 1998. The Freshwater Mussels of Tennessee. University of Tennessee Press: Knoxville, Tennessee. 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.

Stansbery, D.H. 1976. Naiad mollusks. Pages 42-52 in H. Boschung (ed.). Endangered and threatened plants and animals of Alabama. Bulletin of the Alabama Museum of Natural History 2: 1-92.

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, J.D., A.E. Bogan, and J.T. Garner. 2008. Freshwater Mussels of Alabama & the Mobile Basin in Georgia, Mississippi & Tennessee. University of Alabama Press: Tuscaloosa, Alabama. 908 pp.




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