Epioblasma triquetra
Image of Epioblasma triquetra

Photo by David Stagliano 

Key Characteristics

The snuffbox is a medium sized (to 2 inches) mussel that is triangular in shape. Its shell is thick and yellowish on the outside with numerous, broken, dark green rays. Beak sculpture is double looped and the hinge teeth are elevated and compressed.

Status and Rank

  • State Status: E
  • US Status: LE
  • State Rank: S1S2
  • Global Rank: G3


County NameNumber of OccurrencesYear Last Observed
St. Clair102013
St. Joseph42001
Distribution map for Epioblasma triquetra

Updated 5/15/2018. Information is summarized from MNFI's database of rare species and community occurrences. Data may not reflect true distribution since much of the state has not been thoroughly surveyed.


The snuffbox inhabits sand, gravel, or cobble substrates in swift small and medium-sized rivers. Individuals are often buried deep in the sediment.

Specific Habitat Needs

Gravel substrate needed in Mainstem Stream (3rd-4th order), Riffle, River (5th-6th order), Riffle

Natural Community Types


For each species, lists of natural communities were derived from review of the nearly 6,500 element occurrences in the MNFI database, in addition to herbarium label data for some taxa. In most cases, at least one specimen record exists for each listed natural community. For certain taxa, especially poorly collected or extirpated species of prairie and savanna habitats, natural community lists were derived from inferences from collection sites and habitat preferences in immediately adjacent states (particularly Indiana and Illinois). Natural communities are not listed for those species documented only from altered or ruderal habitats in Michigan, especially for taxa that occur in a variety of habitats outside of the state.

Natural communities are not listed in order of frequency of occurrence, but are rather derived from the full set of natural communities, organized by Ecological Group. In many cases, the general habitat descriptions should provide greater clarity and direction to the surveyor. In future versions of the Rare Species Explorer, we hope to incorporate natural community fidelity ranks for each taxon.


The Snuffbox mussel is sensitive to river impoundment, siltation and disturbance, due to its requirement for clean, swift current and relative immobility as an adult. In order to maintain the current populations in Michigan, rivers need to be protected to reduce silt loading and run-off. Maintaining or establishing vegetated riparian buffers can aid in controlling many of the threats to mussels. Control of zebra mussels is critical to preserving native mussels. And as with all mussels, protection of their hosts habitat is also crucial. Because the life cycle of the snuffbox is inherently linked with that of the logperch in Michigan, conservation and management of this fish species is needed to insure that of the Snuffbox.

Survey Methods

Page Citation

Michigan Natural Features Inventory. 2007. Rare Species Explorer (Web Application). Available online at http://mnfi.anr.msu.edu/explorer [Accessed Aug 17, 2018]

More Information

See MNFI Species Abstract


Survey References

Technical References

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