Share your observations

Share your observations of plants or non-game animals with the Natural Heritage Inventory

Rare animals
Find rare and non-game animals.
Rare plants
Learn about plants on the Natural Heritage Working List.
Rare lichens
Discover Wisconsin's lichens.
Natural communities
Explore Wisconsin's natural communities.
Other features
Discover unique resources.
Eagle license plate

Help care for rare plants and animals by ordering an Endangered Resources plate.

Contact information
For information on Wisconsin's rare vertebrate animals, contact:
Rich Staffen
Conservation Biologist
For information on Wisconsin's rare invertebrates, contact:
Jay Watson
Conservation Biologist

Salamander Mussel (Simpsonaias ambigua)



Salamander Mussel (Simpsonaias ambigua), presently listed as a Federal Species of Concern and Threatened in Wisconsin. In Wisconsin, this species is only found in mud, silt or sand substrates beneath medium to large-sized flat rocks and undercut ledges, where its host, the mudpuppy frequents. It occurs in both the Mississippi River and Lake Michigan drainages. It can be very abundant locally, but extremely rare otherwise.

State status

Status and Natural Heritage Inventory documented occurrences in Wisconsin

The table below provides information about the protected status - both state and federal - and the rank (S and G Ranks) for Salamander Mussel (Simpsonaias ambigua). See the Working List Key for more information about abbreviations. Counties shaded blue have documented occurrences for this species in the Wisconsin Natural Heritage Inventory database. The map is provided as a general reference of where occurrences of this species meet NHI data standards and is not meant as a comprehensive map of all observations.

Note: Species recently added to the NHI Working List may temporarily have blank occurrence maps.

Documented locations of Simpsonaias ambigua in the Natural Heritage Inventory Database as of July 2015.
Summary Information
State StatusTHR
Federal Status in WisconsinSOC
State RankS2
Global RankG3
Tracked by NHIY

Species guidance

Note: a species guidance document is not available at this time. Information below was compiled from publication PUB-ER-085-99 (now out-of-print).

Identification: Shell is yellow or brown, smooth, fragile, elongate, and thin. The anterior end is thicker than the posterior end. The male shell is less inflated than the female. Beaks are slightly elevated and somewhat pointed, directed inwardly and toward the anterior. Beak sculpture consists of three to four double-looped bars. One small pseudocardinal tooth is in each valve and the lateral teeth are indistinct. The beak cavity is shallow. The nacre is bluish-white, occasionally tinged with salmon near the beak and iridescent posteriorly. Length to 2 inches (5.1 cm).

Habitat: Found in medium to large rivers on mud or gravel bars but more common under flat slabs of rock, stones or in ledges of underwater cliff faces.

State Distribution: Occurs in the following rivers: Chippewa, Embarrass, Eau Claire, south fork of the Flambeau, Lemonweir, Mississippi, St.Croix, Wisconsin, and the Wolf.

Phenology: The salamander mussel is host specific. Glochidia have only been found on mudpuppies (Necturus maculosus) from October through May.

Management Guidelines: Habitat destruction and river pollution have resulted in mussel declines. Protection of habitat and improvements in water quality along with restriction of dredging, impoundments, sand and gravel mining, and navigational improvements would benefit this species. Due to the specificity of the host species, protection of mudpuppies and their habitats is particularly important.



Salamander Mussel

Photo by Lisie Kitchell, WDNR.

Wildlife Action Plan

Wisconsin Wildlife Action Plan graphic

Natural community (habitat) associations

The table below lists the natural communities that are associated with Salamander Mussel. Only natural communities for which Salamander Mussel is "high" (score=3) or "moderate" (score=2) associated are shown. See the key to association scores for complete definitions. Please see the Wildlife Action Plan to learn how this information was developed.

Natural community Score
Warmwater streams 3
Warmwater rivers 2

Ecological landscape associations

The table below lists the ecological landscape association scores for Salamander Mussel. The scores correspond to the map (3=High, 2=Moderate, 1=Low, 0=None). For more information, please see the Wildlife Action Plan.

This map shows the probability of Salamander Mussel occurring in each of Wisconsin's Ecological Landscapes.  Actual scores can be found in the table to the left.

Back to Top

Landscape-Community combinations of highest ecological priority*

Ecological priorities are the combinations of natural communities and ecological landscapes that provide Wisconsin's best opportunities to conserve important habitats for a given Species of Greatest Conservation Need. The 10 highest scoring combinations are considered ecological priorities and are listed below. More than 10 combinations are listed if multiple combinations tied for 10th place. For more information, please see the Wildlife Action Plan.

* Ecological priority score is a relative measure that is not meant for comparison between species. This score does not consider socio-economical factors that may dictate protection and/or management priorities differently than those determined solely by ecological analysis. Further, a low ecological priority score does not imply that management or preservation should not occur on a site if there are important reasons for doing so locally.

Back to Top

Issues/threats and conservation actions

Conservation actions respond to issues or threats, which adversely affect species of greatest conservation need (SGCN) or their habitats. Besides actions such as restoring wetlands or planting resilient tree species in northern communities, research, surveys and monitoring are also among conservation actions described in the WWAP because lack of information can threaten our ability to successfully preserve and care for natural resources.

Threats/issues and conservations actions for rare animals

Back to Top

Last revised: Thursday, December 22, 2022