Roadless Areas
Home/Species/ Snuffbox

Epioblasma triquetra

(Rafinesque, 1820)

Snuffbox

G2Imperiled (G2G3) Found in 2 roadless areas NatureServe Explorer →
G2ImperiledGlobal Rank
EndangeredIUCN
Very high - highThreat Impact
Snuffbox mussel (Epioblasma triquetra). Photo by U.S. Fish & Wildlife Service, Public Domain (U.S. Government Work), via ECOS.
U.S. Fish & Wildlife Service, https://www.usa.gov/government-works
Identity
Unique IDELEMENT_GLOBAL.2.112023
Element CodeIMBIV16190
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryInvertebrate Animal
IUCNEndangered
Endemicoccurs (regularly, as a native taxon) in multiple nations
KingdomAnimalia
PhylumMollusca
ClassBivalvia
OrderUnionoida
FamilyUnionidae
GenusEpioblasma
Synonyms
Dysnomia triquetra(Rafinesque, 1820)Plagiola triquetra(Rafinesque, 1820)Unio cuneatusSwainson, 1823Unio formosusI. Lea, 1831Unio triangularisBarnes, 1823
Other Common Names
Épioblasme tricorne (FR) Snuffbox mussel (EN)
Concept Reference
Turgeon, D. D., J. F. Quinn, Jr., A. E. Bogan, E. V. Coan, F. G. Hochberg, W. G. Lyons, P. M. Mikkelsen, R. J. Neves, C. F. E. Roper, G. Rosenberg, B. Roth, A. Scheltema, F. G. Thompson, M. Vecchione, and J. D. Williams. 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.
Taxonomic Comments
This species has been placed in the monotypic subgenus Truncilliopsis by Ortmann and Walker (1922) and Johnson (1978). Synonyms include Unio triangularis Barnes, 1823, Unio cuneatus Swainson, 1823, and Unio formosus I. Lea, 1831. Historically, it was placed in the genera Dysnomia and Plagiola (Johnson, 1978).
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2023-12-06
Change Date2023-12-06
Edition Date2023-12-06
Edition AuthorsLipford, M.; Bier (1998); Cummings, K. S. (2nd edition); rev. Cordeiro, J. (2009); rev. T. Cornelisse (2023)
Threat ImpactVery high - high
Range Extent200,000-2,500,000 square km (about 80,000-1,000,000 square miles)
Number of Occurrences21 - 80
Rank Reasons
This species has a moderate range but due to long-term population declines and many ongoing threats, it has a limited number of viable occurrences.
Range Extent Comments
This species occurs in Ontario, Canada, and in the United States from Minnesota to Pennsylvania, south to Alabama and west to Arkansas in streams in the Great Lakes, Ohio, Tennessee, Mississippi, and Arkansas-White-Red Basins (USFWS 2022; GBIF 2023).
Occurrences Comments
As of 2022, there were 56 extant populations of this species in 83 streams (USFWS 2022).
Threat Impact Comments
This species is threatened by oil and gas exploration, coal mining, and the heavy metal and chemical pollutants that result from those activities, land conversion due to urbanization and agriculture, sedimentation due to runoff from land conversion activities, invasive species, dams or other barriers that alter its habitat, host fish distribution, and prevent habitat connectivity and recolonization, and habitat alteration due to climate change, including increased water temperatures, droughts, and flooding (USFWS 2022).
Ecology & Habitat

Description

Shell exterior: Shell small, fairly solid, triangular (males) to somewhat elongate (females) and inflated (particularly in females). Anterior end rounded, posterior end truncated in males, expanded in females. Dorsal and ventral margins straight to slightly curved. Posterior ridge sharply angled, and the posterior slope wide, expanded, and ribbed (especially in females). Umbos swollen and slightly elevated above the hinge line. Beak sculpture of three to four faint, double-looped bars. Periostracum yellow or yellowish green, with numerous dark green rays, blotches or chevron-shaped markings. Length to 2.5 inches.
Shell interior: Pseudocardinal teeth elevated, roughened, relatively thin and compressed; two in the left valve, two in the right, the front one thinner and much smaller. Lateral teeth very short, slightly curved, serrated, and elevated. Beak cavity fairly deep. Nacre pearly white, iridescent posteriorly (Cummings and Mayer, 1992).

Habitat

This species is found in riffles of small and medium creeks, large rivers, and in shoals and wave-washed shores of lakes (Baker 1928; Parmalee and Bogan 1998). Except when spawning, adults are usually burrowed deep in sand, gravel or cobble substrates (USFWS 2012).
Other Nations (2)
United StatesN2
ProvinceRankNative
VirginiaS1Yes
IowaSXYes
West VirginiaS2Yes
IndianaS1Yes
OhioS1Yes
MississippiS1Yes
KentuckyS1Yes
TennesseeS3Yes
MissouriS1Yes
KansasSXYes
MichiganS1Yes
PennsylvaniaS2Yes
New YorkSHYes
ArkansasS1Yes
MinnesotaS1Yes
WisconsinS1Yes
IllinoisS1Yes
AlabamaS1Yes
CanadaN1
ProvinceRankNative
OntarioS1Yes
Threat Assessments
ThreatScopeSeverityTiming
1 - Residential & commercial developmentRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
1.1 - Housing & urban areasRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
2 - Agriculture & aquacultureRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
2.1 - Annual & perennial non-timber cropsRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
2.1.4 - Scale unknown/unrecordedRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
3 - Energy production & miningRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
3.2 - Mining & quarryingRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
7 - Natural system modificationsRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
7.2 - Dams & water management/useRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
8 - Invasive & other problematic species, genes & diseasesRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
8.1 - Invasive non-native/alien species/diseasesRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
8.1.2 - Named speciesRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
9 - PollutionLarge (31-70%)Extreme - seriousHigh (continuing)
9.2 - Industrial & military effluentsLarge (31-70%)Serious or 31-70% pop. declineHigh (continuing)
9.3 - Agricultural & forestry effluentsLarge (31-70%)Serious or 31-70% pop. declineHigh (continuing)
9.3.2 - Soil erosion, sedimentationLarge (31-70%)Serious or 31-70% pop. declineHigh (continuing)
11 - Climate change & severe weatherLarge (31-70%)Serious - moderateHigh (continuing)
11.1 - Habitat shifting & alterationLarge (31-70%)Serious - moderateHigh (continuing)

—

Roadless Areas (2)
Idaho (1)
AreaForestAcres
Bear CreekCaribou-Targhee National Forest118,582
Kentucky (1)
AreaForestAcres
WolfpenDaniel Boone National Forest2,835
References (103)
  1. Ahlstedt, S.A. 1995-1996. Status survey for federally listed endangered freshwater mussel species in the Paint Rock River system, northeastern Alabama, U.S.A. Walkerana 8(19):63-80.
  2. Badra, P.J. and R.R. Goforth. 2003. Freshwater mussel surveys of Great Lakes tributary rivers in Michigan. Report Number MNFI 2003-15 to the Michigan Department of Environmental Quality, Coastal Zone Management Unit, Lansing, Michigan. 40 pp.
  3. Baker, F.C. 1928b. The freshwater Mollusca of Wisconsin: Part II. Pelecypoda. Bulletin of the Wisconsin Geological and Natural History Survey, University of Wisconsin, 70(2): 1-495.
  4. Baker, Richard J. (Natural Heritage and Nongame Research Program, MN Department of Natural Resources). 1997. Review and annotation of fish and mussel watershed distribution maps. Review requested by Ruth Mathews, TNC. November 1997.
  5. Barnhart, C., F. Riusech, and M. Baird. 1998. Hosts of salamander mussel (<i>Simpsonaias ambigua</i>) and snuffbox (<i>Epioblasma triquetra</i>) from the Meramec River system, Missouri. Triannual Unionid Report, 16: 34.
  6. Barr, W.C., S.A. Ahlstedt, G.D. Hickman, and D.M. Hill. 1993-1994. Cumberlandian mollusk conservation program. Activity 8: Analysis of macrofauna factors. Walkerana 7(17/18):159-224.
  7. Biological Resources Division, USGS. 1997. Database of museum records of aquatic species. Compiled by J. Williams (USGS-BRD, Gainesville, FL).
  8. Boepple, J.F. and R.E. Coker. 1912. Mussel resources of the Holston and Clinch rivers of eastern Tennessee. Bureau of Fisheries Document 765. 13 pp.
  9. Bogan, Art (Curator of Aquatic Invertebrates, North Carolina State Museum of Natural Sciences). 1997. Review and annotation of mussel watershed distribution maps for TN. Review requested by Ruth Mathews, TNC. September 1997.
  10. Chapman, E.J. and T.A. Smith. 2008. Structural community changes in freshwater mussel populations of Little Mahoning Creek, Pennsylvania. American Malacological Bulletin, 26: 161-169.
  11. Cicerello, Ronald R. (Kentucky State Nature Preserves). 1997b. Review and annotation of mussel watershed distribution maps. Review requested by Ruth Mathews, TNC. September 1997.
  12. Cicerello, Ronald R. (Kentucky State Nature Preserves). 1997c. Review and annotation of mussel watershed distribution maps. Review requested by Larry Master, TNC. June 1997.
  13. 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.
  14. Clarke, C.F. 1987. The freshwater naiads of Ohio, Part V Wabash River drainage of Ohio. Malacology Data Net, 2(1/2): 19-37.
  15. Coker, R.E., A.F. Shira, H.W. Clark, and A.D. Howard. 1921. Natural history and propagation of fresh-water mussels. Bulletin of the Bureau of Fisheries [Issued separately as U.S. Bureau of Fisheries Document 839] 37(1919-20):77-181 + 17 pls.
  16. Couch, K.J. 1997. An Illustrated Guide to the Unionid Mussels of Kansas. Karen J. Couch. [Printed in Olathe, Kansas]. 124 pp.
  17. Cudmore, B., C.A. MacKinnon, and S.E. Madzia. 2004. Aquatic species at risk in the Thames River watershed, Ontario. Canadian Manuscript Report of Fisheries and Aquatic Sciences 2707. 123 pp.
  18. Cummings, Kevin S. (Illinois Natural History Survey). 1997. Review and annotation of mussel watershed distribution maps. Reviews requested by Christine O'Brien, USGS-BRD. May and July 1997.
  19. Cummings, K.S. and C.A. Mayer. 1992. Field Guide to Freshwater Mussels of the Midwest. Illinois Natural History Survey Manual 5, Illinois. 194 pp.
  20. Cummings, K.S. and C.A. Mayer. 1997. Distributional checklist and status of Illinois freshwater mussels (Mollusca: Unionacea). Pages 129-145 in: K.S. Cummings, A.C. Buchanan, C.A. Mayer, and T.J. Naimo (eds.) Conservation and management of freshwater mussels II: initiatives for the future. Proceedings of a UMRCC Symposium, October 1995, St. Louis, Missouri. Upper Mississippi River Conservation Committee, Rock Island, Illinois.
  21. Cummings, K.S. and J.M. Berlocher. 1990. The naiades or freshwater mussels (Bivalvia: Unionidae) of the Tippecanoe River, Indiana. Malacological Review 23:83-98.
  22. Evermann, B.W. and H.W. Clark. 1918. The Unionidae of Lake Maxinkukee. Proceedings of the Indiana Academy of Science 1917:251-285.
  23. Fisher, B.E. 2006. Current status of freshwater mussels (Order Unionoida) in the Wabash River drainage of Indiana. Proceedings of the Indiana Academy of Science, 115(2): 103-109.
  24. Freshwater Mollusk Conservation Society (FMCS). 2023. The 2023 checklist of freshwater bivalves (Mollusca: Bivalvia: Unionida) of the United States and Canada. Considered and approved by the Bivalve Names Subcommittee October 2023. Online: https://molluskconservation.org/MServices_Names-Bivalves.html
  25. Global Biodiversity Information Facility (GBIF). 2023. Global Biodiversity Information Facility (GBIF) data portal. Online. Available: https://www.gbif.org/ (accessed 2023).
  26. Gordon, M.E. 1982. Mollusca of the White River, Arkansas and Missouri. The Southwestern Naturalist, 27(3): 347-352.
  27. Grabarkiewicz, J.D. 2008. Three years of unionid surveys in Swan Creek, Lower Maumee River watershed, Lucas Co., OH. Final Report to the Ohio Division of Wildlife, Toledo Naturalists' Association, and Metroparks of the Toledo Area, Toledo, Ohio. 18 pp. + app.
  28. Graf, D.L. and K.S. Cummings. 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):1-36.
  29. Haag, W. R. 2019. Reassessing enigmatic mussel declines in the United States. Freshwater Mollusk Biology and Conservation 22(2):43-60.
  30. Harmon, J.L. 1989. Freshwater bivalve mollusks (Bivalvia: Unionidae) of Graham Creek, a small southeastern Indiana stream. Malacology Data Net, 2(5/6): 113-121.
  31. Harmon, J.L. 1992. Naiades (Bivalvia: Unionidae) of Sugar Creek, east fork White River drainage, in central Indiana. Malacology Data Net 3(1-4):31-42.
  32. Harris, J.L. and M.E. Gordon. 1987. Distribution and status of rare and endangered mussels (Mollusca: Margaritiferidae, Unionidae) in Arkansas. Proceedings of the Arkansas Academy of Science, 41: 49-56.
  33. Harris, J.L., P.J. Rust, A.C. Christian, W.R. Posey II, C.L. Davidson, and G.L. Harp. 1997. Revised status of rare and endangered Unionacea (Mollusca: Margaritiferidae, Unionidae) in Arkansas. Journal of the Arkansas Academy of Science, 51: 66-89.
  34. Heard, W.H. 1970. Eastern freshwater mollusks. 1. The south Atlantic and Gulf drainages. In: A.H. Clarke (ed.) Rare and endangered molluscs of North America. Malacologia 10:1-56.
  35. Heath, D. and L. Kitchel. 1997. Review and annotation of mussel watershed distribution maps by the Wisconsin Department of Natural Resources. Review requested by Ruth Mathews, TNC. September 1997.
  36. Hill, D.M. 1986. Cumberlandian mollusk conservation program, activity 3: identification of fish hosts. Office of Natural Resources and Economic Development, Tennessee Valley Authority, Knoxville, Tennessee. 55 pp.
  37. Hillegass, K.R. and M.C. Hove. 1997. Suitable fish hosts for glochidia of three freshwater mussels: strange floater, ellipse, and snuffbox. Triannual Unionid Report, 13: 25.
  38. Hornbach, D.J. 1994. The factors influencing the distribution of mussels in the Lower St. Croix River. Reported submitted to Conservation Biology Research Grant Program, Division of Ecological Services, Minnesota Department of Natural Resources, February 20, 1994. 23 pp.
  39. Horne, F.R. and S. McIntosh. 1979. Factors influencing distribution of mussels in the Blanco River of central Texas. The Nautilus 94(4):119-133.
  40. Hove, M. and A.R. Kapuscinski. 1998. Ecological relationships between six rare Minnesota mussels and their host fishes. Final Report to the Minnesota Department of Natural Resources, Natural Heritage and Nongame Research Program, St. Paul, Minnesota. 17 pp.
  41. Hove, M.C., K.R. Hillegas, J.E. Kurth, V.E. Pepi, C.J. Lee, K.A. Knudsen, A.R. Kapuscinski, P.A. Mohoney, and M.M. Bomier. 2000. Considerations for conducting host suitability studies. Pages 27-34 in R.A. Tankersley, D.I. Warmolts, G.T. Watters, B.J. Armitage, P.D. Johnson, and R.S. Butler (eds.). Freshwater Mollusk Symposia Proceedings. Part I. Proceedings of the Conservation, Captive Care and Propagation of Freshwater Mussels Symposium. Ohio Biological Survey Special Publication, Columbus, Ohio. 274 pp.
  42. Hove, M., M. Berg, K. Dietrich, C. Gonzales, D. Hornbach, K. Juleen, M. Ledford, M. Marzec, M. McGill, C. Nelson, B.J. Ritger, J. Selander, and A. Kapuscinski. 2003c. High school students participate in snuffbox host suitability trials. Ellipsaria 5(3): 19-20.
  43. Howard, A. D. 1915. Some exceptional cases of breeding among the Unionidae. The Nautilus 29:4-11.
  44. Hubbs, D. 2002. Monitoring and management of endangered mussels. 2001-02 Annual Report Project 7365, Tennessee Wildlife Resources Agency, Nashville, Tennessee. 3 pp.
  45. Indiana Natural Heritage Data Center. 2006-2007. Personal communication with Jay Cordeiro (NatureServe) about freshwater mussel distribution in Indiana in 2006 and 2007.
  46. Isom, B.G., P. Yokley, Jr., and C.H. Gooch. 1973. Mussels of Elk River Basin in Alabama and Tennessee- 1965-1967. American Midland Naturalist 89(2):437-442.
  47. Johnson, R.I. 1978. Systematics and zoogeography of <i>Plagiola </i>(= <i>Dysnomia </i>= <i>Epioblasma</i>), an almost extinct genus of freshwater mussels (Bivalvia: Unionidae) from middle North America. Bulletin of the Museum of Comparative Zoology, 148(6): 239-320.
  48. Jones, R.L., W.T. Slack, and P.D. Hartfield. 2005. The freshwater mussels (Mollusca: Bivalvia: Unionidae) of Mississippi. Southeastern Naturalist, 4(1): 77-92.
  49. Lefevre, G. and W. T. Curtis. 1912. Studies on the reproduction and artificial propagation of fresh-water mussels. Bulletin of the Bureau of Fisheries 30:102-201.
  50. Lyons, M.S., R.A. Krebs, J.P. Holt, L.J. Rundo, and W. Zawiski. 2007. Assessing causes of change in the freshwater mussels (Bivalvia: Unionidae) in the Black River, Ohio. American Midland Naturalist, 158: 1-15.
  51. Major, Smoot (Tennessee Division of Natural Heritage). 1997. Review and annotation of fish and mussel watershed distribution maps. Review requested by Ruth Mathews, TNC on 19 August 1997.
  52. Mann, Tom. (Mississippi Natural Heritage Program. Mississippi Museum of Natural Science). 1997. Review and annotation of fish and mussel watershed distribution maps. Review requested by Ruth Mathews, TNC.
  53. Marangelo, P.J. and D.L. Strayer. 2000. The freshwater mussels of the Tonawanda Creek basin in western New York. Walkerana, 11(25): 97-106.
  54. Master, Lawrence L. (Chief Zoologist, TNC). 1997a. Review and annotation of fish and mussel watershed distribution maps. Reviews coordinated by Larry Master and Ruth Mathews, TNC.
  55. Master, L. L. 1996. Synoptic national assessment of comparative risks to biological diversity and landscape types: species distributions. Summary Progress Report submitted to Environmental Protection Agency. The Nature Conservancy, Arlington, Virginia. 60 pp.
  56. Master, L. L. and A. L. Stock. 1998. Synoptic national assessment of comparative risks to biological diversity and landscape types: species distributions. Summary Report submitted to Environmental Protection Agency. The Nature Conservancy, Arlington, VA. 36 pp.
  57. Meek, S. E., and H.W. Clark. 1912. The mussels of the Big Buffalo Fork of White River, Arkansas. Report and Special Papers of the U.S. Fish Commission [Issued separately as U.S. Bureau of Fisheries Document 759] 1911:1-20.
  58. Metcalfe-Smith, J.L. and B. Cudmore-Vokey. 2004. National general status assessment of freshwater mussels (Unionacea). National Water Research Institute / NWRI Contribution No. 04-027. Environment Canada, March 2004. Paginated separately.
  59. Metcalfe-Smith, J.L., J. Di Maio, S.K. Staton, and S.R. De Solla. 2003. Status of the freshwater mussel communities of the Sydenham River, Ontario, Canada. American Midland Naturalist 150:37-50.
  60. Michigan Natural Features Inventory. 2025. Rare Species Explorer (Web Application). Available online at http://mnfi.anr.msu.edu/explorer
  61. Mirarchi, R.E., et al. 2004a. 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.
  62. Mirarchi, R.E., J.T. Garner, M.F. Mettee, and P.E. O'Neil. 2004b. Alabama wildlife. Volume 2. Imperiled aquatic mollusks and fishes. University of Alabama Press, Tuscaloosa, Alabama. xii + 255 pp.
  63. Mohler, J.W., P. Morrison, and J. Haas. 2006. The mussels of Muddy Creek on Erie National Wildlife Refuge. Northeastern Naturalist 13(4):569-582.
  64. MolluscaBase eds. 2024. MolluscaBase. Accessed at https://www.molluscabase.org
  65. Moyle, P., and J. Bacon. 1969. Distribution and abundance of molluscs in a fresh water environment. Journal of the Minnesota Academy of Science 35(2/3):82-85.
  66. Oesch, R.D. 1995. Missouri Naiades. A Guide to the Mussels of Missouri. Second edition. Missouri Department of Conservation: Jefferson City, Missouri. viii + 271 pp.
  67. Ortmann, A.E. and B. Walker. 1922. On the nomenclature of certain North American naiades. Occasional Papers of the Museum of Zoology, University of Michigan, 112: 1-75.
  68. Parmalee, P.W. 1967. The freshwater mussels of Illinois. Illinois State Museum, Popular Science Series 8:1-108.
  69. Parmalee, P.W. and A.E. Bogan. 1998. The Freshwater Mussels of Tennessee. University of Tennessee Press: Knoxville, Tennessee. 328 pp.
  70. Sargent, Barbara (West Virginia Natural Heritage Program). 1997. Review and annotation of mussel watershed distribution maps. Review requested by Ruth Mathews, TNC. September 1997.
  71. Schanzle, R.W., G.W. Kruse, J.A. Kath, R.A. Klocek, and K.S. Cummings. 2004. The freshwater mussels (Bivalvia: Unionidae) of the Fox River basin, Illinois and Wisconsin. Illinois Natural History Biological Notes, 141: 1-35.
  72. Schneider, Kathryn (New York Natural Heritage Program). 1997. Review and annotation of fish and mussel watershed distribution maps. Review requested by Larry Master and Ruth Mathews, TNC. September 1997.
  73. Sherman, R.A. 1993. Glochidial release and reproduction of the snuffbox mussel, <i>Epioblasma triquetra</i>; timing in southern Michigan. [abstract]. Bulletin of the North American Benthological Society, 10(1): 197.
  74. Sherman, Renée A. (University of Michigan, Museum of Zoology). 1997. Review and annotation of mussel watershed distribution maps. Review requested by Christine O'Brien, USGS-BRD. June 1997.
  75. Sietman, B.E. 2003. Field Guide to the Freshwater Mussels of Minnesota. Minnesota Department of Natural Resources: St. Paul, Minnesota. 144 pp.
  76. Simpson, C.T. 1899. The pearly fresh-water mussels of the United States; their habits, enemies, and diseases, with suggestions for their protection. Bulletin of the U.S. Fish Commission [Issued separately as U.S. Bureau of Fisheries Document 413] 18(1898):279-288.
  77. Smith, P.W. 1971. Illinois streams: A classification based on their fishes and an analysis of factors responsible for disappearance of native species. Illinois Natural History Survey Biological Notes 76:1-14.
  78. Smith, T.A. and D. Crabtree. 2010. Freshwater mussel (Unionidae: Bivalvia) distributions and densities in French Creek, Pennsylvania. Northeastern Naturalist 17(3):387-414.
  79. Snyder, N. and H. Snyder. 1969. A comparative study of mollusk predation by Limpkins, Everglade Kites, and Boat-tailed Grackles. Eighth Annual Report of the Cornell Laboratory of Ornithology 8:177-223.
  80. Spoo, A. 2008. The Pearly Mussels of Pennsylvania. Coachwhip Publications: Landisville, Pennsylvania. 210 pp.
  81. Strayer, D. 1980. The freshwater mussels (Bivalvia: Unionidae) of the Clinton River, Michigan, with comments on man's impact on the fauna, 1870-1978. The Nautilus 94(4):142-149.
  82. Strayer, D. 1983. The effects of surface geology and stream size on freshwater mussel (Bivalvia, Unionidae) distribution in southeastern Michigan, U.S.A. Freshwater Biology 13:253-264.
  83. Strayer, D. L. 1999. Use of flow refuges by unionid mussels in rivers. Journal of the North American Benthological Society 18(4):468-476.
  84. Strayer, D. L., and J. Ralley. 1993. Microhabitat use by an assemblage of stream-dwelling unionaceans (Bivalvia) including two rare species of <i>Alasmidonta</i>. Journal of the North American Benthological Society 12(3):247-258.
  85. Strayer, D.L. and K.J. Jirka. 1997. The Pearly Mussels of New York State. New York State Museum Memoir 26. The University of the State of New York. 113 pp. + figures.
  86. Tiemann, J.S.. 2006. Freshwater mussel (Bivalvia: Unionidae) survey of the Wakurusa River basin, Kansas. Transaction of the Kansas Academy of Science, 109(3/4): 221-230.
  87. Trdan, R.J. and W.R. Hoeh. 1993. Relocation of two state-listed freshwater mussel species (<i>Epioblasma torulosa rangiana</i> and <i>Epioblasma triquetra</i>) in Michigan. Pages 100-105 in K.S. Cummings, A.C. Buchanan, and L.M. Koch. (eds.). Conservation and Management of Freshwater Mussels. Proceedings of a UMRCC Symposium, 12-14 October 1992, St. Louis, Missouri. Upper Mississippi River Conservation Committee, Rock Island, Illinois. 189 pp.
  88. Turgeon, D. D., J. F. Quinn, Jr., A. E. Bogan, E. V. Coan, F. G. Hochberg, W. G. Lyons, P. M. Mikkelsen, R. J. Neves, C. F. E. Roper, G. Rosenberg, B. Roth, A. Scheltema, F. G. Thompson, M. Vecchione, and J. D. Williams. 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.
  89. U.S. Fish and Wildlife Service (UFWS). 2023. Initiation of 5-Year Status Reviews of Five Listed Animal and Plant Species. Notice of initiation of reviews; request for information. Federal Register 88(9): 2368-2369.
  90. U.S. Fish and Wildlife Service (USFWS). 2010. Endangered and threatened wildlife and plants; listing the rayed bean and snuffbox as endangered; proposed rule. Federal Register 75(211):67552-67583.
  91. U.S. Fish and Wildlife Service (USFWS). 2012. Endangered and threatened wildlife and plants; determination of endangered status for the rayed bean and snuffbox mussels throughout their ranges. Federal Register 77(30): 8632-8665.
  92. U.S. Fish and Wildlife Service (USFWS). 2018. Snuffbox (<i>Epioblasma triquetra</i>), five year review: summary and evaluation. U.S. Fish and Wildlife Service Midwest Region Ecological Services Field Office Columbus, Ohio. 60 pp.
  93. U.S. Fish and Wildlife Service (USFWS). 2022. Species status assessment report for the snuffbox. May 2022 (Version 1.0). Ohio Ecological Services Field Office, Columbus, Ohio.
  94. Van der Schalie, H. 1938. The naiad fauna of the Huron River in southeastern Michigan. Miscellaneous Publication of the Museum of Zoology, University of Michigan 40:7-78.
  95. Watters, G.T. 1992b. Distribution of the Unionidae in south central Ohio. Malacology Data Net 3(1-4):56-90.
  96. Watters, G. T. 1992. Unionids, fishes, and the species-area curve. Journal of Biogeography 19:481-490.
  97. Watters, G.T., M.A. Hoggarth, and D.H. Stansbery. 2009b. The Freshwater Mussels of Ohio. Ohio State University Press: Columbus, Ohio. 421 pp.
  98. Watters, G.T., T. Menker, S. Thomas, and K. Luehnl. 2005. Host identifications or confirmations. Ellipsaria, 7(2): 11-12.
  99. 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.
  100. Williams, J. D., A. E. Bogan, R. S. Butler, K. S. Cummings, J. T. Garner, J. L. Harris, N. A. Johnson, and G. T. Watters. 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.
  101. Williams, J. D., M. L. Warren, Jr., K. S. Cummings, et al. 1992b. Conservation status of freshwater mussels of the United States and Canada. Fisheries 18:6-22 + errata.
  102. Williams, J. D., M. L. Warren, Jr., K. S. Cummings, J. L. Harris, and R. J. Neves. 1993. Conservation status of freshwater mussels of the United States and Canada. Fisheries 18(9):6-22.
  103. Yeager, B.L. and C.F. Saylor. 1995. Fish hosts for four species of freshwater mussels (Pelecypoda: Unionidae) in the Upper Tennessee River drainage. American Midland Naturalist, 133(1): 1-6.