Lampsilis fasciola
Wavyrayed lampmussel

Key Characteristics

The wavy-rayed lampmussel is a medium sized (to 3.5 inches) mussel with a moderately thick, rounded to ovate shell. The beak is slightly elevated above the hinge line and the beak sculpture consists of 3 to 5 indistinct wavy ridges. The shell is compressed to inflated (females) in shape and the anterior end is rounded with the posterior end bluntly pointed in males and rounded in females. The shell color ranges from yellow to yellowish green with numerous thin wavy green rays. The nacre is white and often iridescent posteriorly.

Status and Rank

  • State Status: T
  • State Rank: S2
  • Global Rank: G5


County NameNumber of OccurrencesYear Last Observed
St. Clair82011
Distribution map for Lampsilis fasciola

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 wavy-rayed lampmussel occurs in small-medium sized shallow streams, in and near riffles, with good current. It rarely occurs in medium rivers. The substrate preference is sand and/or gravel (Watters 1993).

Specific Habitat Needs

Sand or gravel substrates needed in Mainstem Stream (3rd-4th 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.


Like other mussels, threats to the wavy-rayed lampmussel include: natural flow alterations, siltation, channel disturbance, point and non-point source pollution, and exotic species. Maintenance or establishment of vegetated riparian buffers can help protect mussel habitats from many of their threats. Control of zebra mussels is critical to preserving native mussels. Smallmouth bass are hosts to this species and so must be considered when managing for the wavy-rayed lampmussel.

Survey Methods

Page Citation

Michigan Natural Features Inventory. 2007. Rare Species Explorer (Web Application). Available online at [Accessed Aug 17, 2018]

More Information

See MNFI Species Abstract


Survey References

Technical References

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