Toxolasma lividus
Purple lilliput

Key Characteristics

The purple lilliput is a small (to 1 inch) mussel with a relatively heavy and inflated shell. The beak is inflated over the hinge line and the beak sculpture consists of 3 to 4 ridges. The lateral teeth are well developed, as are the cardinal teeth, two in the left valve and one in the right valve. The anterior end is rounded and the posterior end is pointed to rounded in males and truncated in females. The shell is smooth (except for growth lines) and light to dark green or brown, darkening with age. The nacre is distinctly purple.

Status and Rank

  • State Status: E
  • State Rank: S1
  • Global Rank: G3Q


County NameNumber of OccurrencesYear Last Observed
Distribution map for Toxolasma lividus

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 purple lilliput occurs in small to medium sized streams, and less often in large rivers and lakes. It occurs most often in well pack sand or gravel in water depths less than 1 m.

Specific Habitat Needs

Gravel substrate needed in Headwater Stream (1st-2nd order), Riffle, Headwater Stream (1st-2nd order), Pool, Headwater Stream (1st-2nd order), Run, Mainstem Stream (3rd-4th order), Riffle, Mainstem Stream (3rd-4th order), Pool, Mainstem Stream (3rd-4th order), Run, Inland Lake, Littoral, Benthic, Inland Lake, Pelagic, Benthic

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 purple lilliput 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. And as with all mussels, protection of their hosts habitat is also crucial.

Survey Methods

Page Citation

Michigan Natural Features Inventory. 2007. Rare Species Explorer (Web Application). Available online at [Accessed Sep 22, 2018]

More Information

See MNFI Species Abstract


Survey References

Technical References

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