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The Nonindigenous Occurrences section of the NAS species profiles has a new structure. The section is now dynamically updated from the NAS database to ensure that it contains the most current and accurate information. Occurrences are summarized in Table 1, alphabetically by state, with years of earliest and most recent observations, and the tally and names of drainages where the species was observed. The table contains hyperlinks to collections tables of specimens based on the states, years, and drainages selected. References to specimens that were not obtained through sighting reports and personal communications are found through the hyperlink in the Table 1 caption or through the individual specimens linked in the collections tables.



Sphaerium corneum
Sphaerium corneum
(European fingernail clam)
Mollusks-Bivalves
Exotic
Collection Info
Point Map
Species Profile
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Sphaerium corneum Linnaeus, 1758
Common name: European fingernail clam
Taxonomy: available through www.itis.govITIS logo

Identification: This fingernail clam has an oval, thin shelled, lustrous brown to gray, and somewhat inflated shell with a height to length ratio of 0.80–0.88. Juveniles’ shells are more yellow. The dorsal shell margin is curved and there are low central beaks with straight edges on either side. The shell is covered in evenly spaced striae that become finer and fade out toward the beaks. The narrow 4th and 2nd cardinal teeth are very close to parallel and the former overlaps the latter. The narrow and curved 3rd cardinal is parallel to the hinge plate and expanded and often bifurcate posteriorly (Clarke 1981, Herrington 1962, Mackie et al. 1980, Mackie 2000, Mackie 2007 and Peckarsky et al. 1993).

Sphaerium corneum and Sphaerium nitidum are difficult to separate as they are closely related. Their similar shapes, thin shells, and fine striae makes S. nitidum look like a smaller form of S. corneum. The only reliable way to separate the two species without opening the shell is that S. nitidum has a shiny to glossy shell with uniformly spaced striae going up and over the beak and a short and narrow hinge. While S. corneum shell silky to dull, striae are irregularly spaced and faded out in the beak, and hinge moderately thick and long (most of the length of the shell).

Sphaerium corneum can grow to approximately 9–13.5 mm in length (Clarke 1981, Herrington 1962, Letarte and Vaillancourt 1986, Mackie 2000).
Size: up to 14 mm
Native Range: Sphaerium corneum is native to Eurasia (Clarke 1981, Herrington 1962).
Hydrologic Unit Codes (HUCs) Explained
Interactive maps: Point Distribution Maps

Nonindigenous Occurrences:

Table 1. States with nonindigenous occurrences, the earliest and latest observations in each state, and the tally and names of HUCs with observations†. Names and dates are hyperlinked to their relevant specimen records. The list of references for all nonindigenous occurrences of Sphaerium corneum are found here.

StateFirst ObservedLast ObservedTotal HUCs with observations†HUCs with observations†
FL196819681Peace
GA197119711Oostanaula
IL195819581Chicago
MI196920193Cheboygan; Lake St. Clair; Tacoosh-Whitefish
NY190020086Headwaters St. Lawrence River; Lake Champlain; Lake Erie; Lake Ontario; Lower Hudson; Niagara River
OH201020232Cuyahoga; Lake Erie
TN197119711Upper Duck
VT196219621Richelieu River

Table last updated 4/15/2026

† Populations may not be currently present.
Ecology:  

HABITAT: Found in freshwater lakes and slow-moving rivers; prefers eutrophic, shallow waters, vegetation; lives in the sediment.  Sphaerium corneum occurs in lotic and lentic water bodies. It often prefers somewhat eutrophied, more lentic habitats, but it cannot tolerate extremely high organic pollution.  Nor does it tolerate desiccation well. Sphaerium corneum has a high capacity for anaerobiosis and is able to survive anoxic conditions for around 400 days at 0ºC and for 9 days at 20ºC. Sphaerium corneum prefers hard waters with high magnesium, calcium, and bicarbonate concentrations. It is found on fine sand, mud, silt, organic matter, and sometimes on gravel. In Lake Michigan it is found down to 10 m. Additional data has shown this species to have a maximum depth reported of 38.5m in Lake Ontario in 1964 (Hiltunen 1969).

In Lake Superior, densities can reach 61 clams per m2 and in the St. Lawrence River they can reach 500–8000 clams per m2 (Boycott 1936, Clarke 1981, Dussart 1979, Grigorovich et al. 2003, Herrington 1962, Hinz 1977, Holopainen 1987, Krieger 1984, Letarte and Vaillancourt 1986, Mackie et al. 1980, Mackie 2000, Watson and Ormerod 2005).            

FOOD WEB: Sphaerium corneum is mainly a filter feeder but can also deposit feed. It prefers diatoms but also ingests other types of phytoplankton. Sphaerium corneum is capable of climbing up aquatic macrophytes, which aids it to filter feed (Bishop and DeGaris 1976, Mackie 2000). In Europe, S. corneum is host to Phyllodistomum spp., which are digenean parasites. The common toad Bufo bufo can aid S. corneum in dispersing in Europe, as the clam can attach to the amphibian’s toe and thus be transferred from one place to another (Kwet 1995, Petkeviciutie et al. 2004).

LIFE HISTORY: Can live up to 3 years, mature at 4 mm (sexually mature as early as 3 months old in Europe). Individuals in the St. Lawrence River live to 1 or 1 and a half, while in Europe they can sometimes live to 2 or 3. S. corneum is hermaphroditic and ovoviviparous. Eggs incubated in a brood-sac in the parent; embryos develop and are released as miniature adults.  Sexually mature adults can carry 1–20 embryos, occasionally more. Parturition in the St. Lawrence River usually occurs in the spring (Clarke 1981, Dussart 1979, Letarte and Vaillancourt 1986, Letarte and Vaillancourt 1988, Mackie 2000).
Means of Introduction: Sphaerium corneum was likely introduced via shipping, probably in solid ballast that was in use at the turn of the century (Grigorovich et al. 2000, Grigorovich et al. 2003, Mills et al. 1993).
Status: Established where recorded, but most common in Lake Erie and Lake Ontario, and uncommon in Lake Huron, where it is uncertain if populations are permanently established.
Impact of Introduction:

A) Realized: In Lake Ontario and Cayuga Lake (part of the Lake Ontario drainage in New York state), S. corneum has been recorded as a host to the oligochaete Chaetogaster limnaei limnaei. This oligochaete is probably quite widespread in North America, where it is typically a commensal of native snails, some other native Sphaerium spp., and at least one native limpet species (Barbour 1977).  

B) Potential: S. corneum hosts such digenean species as Crepidostomum transmarinum, Bunodera lucipercae, and Phyllodistomum simile in North America. These species have been recorded from the Ottawa River, which flows into the St. Lawrence River in Canada (Mackie 1976, Mackie 2000).
References: (click for full references)

Barbour, M.T. 1977. Chaetogaster limnaei limnaei (Oligochaeta: Naididae) inhabiting the mantle cavity of the pill clam Sphaerium. Transactions of the American Microscopical Society 96(1):141-142.

Bishop, M.J., and H. DeGaris. 1976. A note on population densities of Mollusca in the River Great Ouse at Ely, Cambridgeshire. Hydrobiologia 48(3):195-197.

Borchert, J., L. Karbe, and J. Westendorf. 1997. Uptake and metabolism of benzo(a)pyrene absorbed to sediment by the freshwater invertebrate species Chironomus riparius and Sphaerium corneum. Bulletin of Environmental Contamination and Toxicology 58:158-165.

Boycott, A.E. 1936. The habitats of fresh-water Mollusca in Britain. The Journal of Animal Ecology 5(1):116-186.

Clarke, A.H. 1981. French translation by A. La Rocque. Les Mollusques d’eau douce du Canada. Musée national des sciences naturelles, Musées nationaux du Canada. 447 pp.

Clarke, K.B. 1987. Trouble from the fresh water mussel (Sphaerium corneum Lin). Journal of the Institution of Water and Environmental Management 1(3):348.

Dussart, G.B.J. 1979. Sphaerium corneum (L.) and Pisidium spp. Pfeiffer - the ecology of freshwater bivalve molluscs in relation to water chemistry. Journal of Molluscan Studies 45(1):18-34.

Grigorovich, I.A., A.V. Korniushin, and H.J. MacIsaac. 2000. Moitessier’s pea clam Pisidium moitessierianum (Bivalvia, Sphaeriidae): a cryptogenic mollusk in the Great Lakes. Hydrobiologia 435:153-165.

Grigorovich, I.A., A.V. Korniushin, D.K. Gray, I.C. Duggan, R.I. Colautti, and H.J. MacIsaac. 2003. Lake Superior: an invasion coldspot? Hydrobiologia 499:191-210.

Heinonen, Jari, J Kukkonen, O-P Penttinen, and IJ Holopainen.  1997.  Effects of hypoxia on valve-closure time and bioaccumulation of 2,4,5-trichlorophenol by the Freshwater clam Sphaerium corneum [L.].  Ecotoxicology and Environmental Safety 36(1)49-56.

Herrington, H.B. 1962. A revision of the Sphaeriidae of North America (Mollusca: Pelecypoda). Museum of Zoology, University of Michigan, Miscellaneous Publications 118. 74 pp 7 plates.

Hinz, W. 1977. Space as a limiting factor of a pond outlet dwelling Sphaerium corneum population (Mollusca, Lamellibranchiata). Decheniana 130:222-228.

Holopainen, I.J. 1987. Seasonal variation of survival time in anoxic water and the glycogen content of Sphaerium corneum and Pisidium amnicum (Bivalvia, Pisidiidae). American Malacological Bulletin 5(1):41-48.

Krieger, K.A. 1984. Benthic macroinvertebrates as indicators of environmental degradation in the southern nearshore zone of the central basin of Lake Erie. Journal of Great Lakes Research 10(2):197-209.

Kwet, A. 1995. The common toad (Bufo bufo) as a vector host of the bivalve Sphaerium corneum. Salamandra 31(1):61-64.

Letarte, Y., and G. Vaillancourt. 1986. Life cycle and distribution of Sphaerium corneum (Mollusca: Bivalvia, Sphaeriidae) in Lake Saint Pierre, St. Lawrence River, Quebec, Canada. Naturaliste Canadien (Quebec) 113(2):201-210.

Letarte, Y., and G. Vaillancourt. 1988. Biomass production, productivity and reproduction in a population of Sphaerium corneum (Linnaeus) (Mollusca: Bivalvia, Sphaeriidae) from Lake St. Pierre, St. Lawrence River, Quebec, Canada. Naturaliste Canadien (Quebec) 115(1):65-76.

Mackie, G.L. 1976. Trematode parasitism in the Sphaeriidae clams, and the effects in three Ottawa River species. Nautilus 90:36-41.

Mackie, G.L. 2000. Ballast water introductions of Mollusca. Pp. 219-254 in R. Claudi and J. H. Leach, eds. Nonindigenous Freshwater Organisms: Vectors, Biology and Impacts. CRC Press LLC, Boca Raton, Florida. 464 pp.

Mackie, G.L., D.S. White, and T.W. Zdeba. 1980. A guide to freshwater mollusks of the Laurentian Great Lakes with special emphasis on the genus Pisidium. Environmental Research Laboratory, Office of Research and Development, U. S. Environmental Protection Agency, Duluth, Minnesota 55804. 144 pp.

Mills, E.L., J.H. Leach, J.T. Carlton, and C.L. Secor. 1993. Exotic species in the Great Lakes: a history of biotic crises and anthropogenic introductions. Journal of Great Lakes Research 19(1):1-54.

Peckarsky, B.L., P.R. Fraissinet, M.A. Penton, and D.J. Conklin Jr. 1993. Freshwater Macroinvertebrates of Northeastern North America. Cornell University Press, Ithaca, New York State. 442 pp.

Penttinen, O., J. Kukkonen, and J. Pellinen. 1996. Preliminary study to compare body residues and sublethal energetic responses in benthic invertebrates exposed to sediment-bound 2,4,5-trichlorophenol. Environmental Toxicology and Chemistry 15(2):160-166.

Petkeviciutie, R., V. Stunzenas, and G. Stanevicte. 2004. Cytogenetic and sequence comparison of adult Phyllodistomum (Digenea: Gargoderidae) from the three-spined stickleback with larvae from two bivalves. Parasitology 129(6):771-778.

Verrengia Guerrero, N.R., M.G. Taylor, N.A. Davies, M.A.M. Lawrence, P.A. Edwards, K. Simkiss, and E.A. Wider. 2002. Evidence of differences in the biotransformation of organic contaminants in three species of freshwater invertebrates. Environmental Pollution 117:523-530.

Watson, A.M., and S.J. Ormerod. 2005. The distribution and conservation of threatened Sphaeriidae on British grazing marshland. Biodiversity and Conservation 14(9):2207-2220.

Other Resources:
Great Lakes Water Life

Author: Kipp, R.M., A.J. Benson, J. Larson, and A. Fusaro
Revision Date: 4/13/2026

 Citation Information:
Kipp, R.M., A.J. Benson, J. Larson, and A. Fusaro, 2026, Sphaerium corneum Linnaeus, 1758: U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, https://nas.er.usgs.gov/Queries/FactSheet.aspx?SpeciesID=131, Revision Date: 4/13/2026, Access Date: 4/15/2026

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.

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The data represented on this site vary in accuracy, scale, completeness, extent of coverage and origin. It is the user's responsibility to use these data consistent with their intended purpose and within stated limitations. We highly recommend reviewing metadata files prior to interpreting these data.

Citation information: U.S. Geological Survey. [2026]. Nonindigenous Aquatic Species Database. Gainesville, Florida. Accessed [4/15/2026].

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