Simpsonaias ambigua
Salamander mussel

Key Characteristics

The salamander mussel has a small (to 2 inches), thin, elliptical shell. The anterior and posterior edges are rounded and the dorsal and ventral margins are parallel. The beak is closer to the anterior edge than the posterior edge and is sharp and pointed forward. The beak sculpture consists of 3 to 5 parallel double-looped bars. The lateral teeth are usually absent and the hinge teeth are incomplete and irregular and only one cardinal tooth is present in each valve. The outside shell is smooth and dull yellow-tan to dark brown with no rays and the nacre is bluish white and iridescent.

Status and Rank

  • State Status: E
  • State Rank: S1
  • Global Rank: G3


County NameNumber of OccurrencesYear Last Observed
St. Clair42003
Distribution map for Simpsonaias ambigua

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 salamander mussel is found in medium to large rivers and lakes. It is usually found in silt or sand under flat stones. Although this mussel is rare, it is usually abundant in patches. Its presence is usually linked to that of the mudpuppy (Necturus maculosus), its host.

Specific Habitat Needs

Flat rocks or stones needed in Mainstem Stream (3rd-4th order), Riffle, Mainstem Stream (3rd-4th order), Pool, Mainstem Stream (3rd-4th order), Run, River (5th-6th order), Riffle, River (5th-6th order), Pool, River (5th-6th order), Run

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 salamander 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 host’s 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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