Plants and Animals

Alasmidonta viridis Slippershell

Key Characteristics

The slippershell is a small (to 1.5 inches) mussel with a straight ventral margin. Beak sculpture has three to four ridges or loops. The lateral teeth are irregular and poorly developed; where as the cardinal teeth are triangular with one in the right valve and two in the left valve. The shell is yellowish-brown and marked with fine green rays with a square posterior end and a rounded anterior end. The nacre is white and often iridescent towards the posterior end of the shell.

Status and Rank

US Status:
State Status: T - Threatened (legally protected)
Global Rank: G4G5 - Rank is uncertain, ranging from apparently secure to secure
State Rank: S2S3 - Rank is uncertain, ranging from imperiled to vulnerable

Occurrences

CountyNumber of OccurrencesYear Last Observed
Alcona21925
Allegan22013
Alpena31932
Barry42013
Bay1
Benzie11925
Berrien52009
Branch32000
Calhoun42000
Cass31940
Chippewa22007
Clare42018
Clinton52010
Crawford41934
Delta11930
Dickinson52009
Eaton42002
Emmet12011
Genesee22001
Gladwin71981
Gratiot22015
Hillsdale222015
Huron51942
Ingham92018
Ionia52016
Iosco21937
Iron1
Isabella12015
Jackson112017
Kalamazoo1
Kent152017
Lake1
Lapeer72016
Lenawee142016
Livingston112007
Luce1
Mackinac22007
Macomb142007
Mecosta21934
Menominee112010
Midland32012
Missaukee52002
Monroe102017
Montcalm102015
Montmorency31944
Muskegon2
Newaygo31949
Oakland182007
Oceana11934
Ogemaw62003
Osceola92002
Oscoda22016
Ottawa1
Presque Isle21940
Roscommon31934
Saginaw12011
Sanilac52010
Schoolcraft11929
Shiawassee32001
St. Clair102016
St. Joseph52016
Tuscola62011
Van Buren82009
Washtenaw182010
Wayne81933
Wexford21926

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.

Habitat

The slippershell typically occurs in creeks and headwaters of rivers in sand or gravel substrates. Occasionally, they occur in larger rivers and lakes and in mud substrates.

Specific Habitat Needs

Sand, gravel substrates needed in: Headwater Stream (1st-2nd order), RiffleHeadwater Stream (1st-2nd order), RunInland Lake, Littoral, BenthicMainstem Stream (3rd-4th order), RunMainstem Stream (3rd-4th order), Riffle.

Natural Community Types

  • Headwater stream (1st-2nd order), riffle
  • Headwater stream (1st-2nd order), run
  • Inland lake, littoral, benthic
  • Mainstem stream (3rd-4th order), run
  • Mainstem stream (3rd-4th order), riffle

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.

Management Recommendations

The slippershell requires clear, clean water and substrates for survival. Like other mussels, threats include: siltation, poor water quality, point and non-point source pollution, and alteration of natural flow regimes. Maintenance or establishment of vegetated riparian buffers can help protect mussel habitats from these threats. Additionally, zebra mussels and other exotic species are a major threat to all mussels. Hence, control and management of exotic species also help protect native mussel species. And as with all mussels, protection of their hosts habitat is also crucial.

Active Period

Survey Methods

Aqua-scope searches

Survey Period: From first week of April to first week of October

Snorkeling searches

Survey Period: From first week of April to first week of October

SCUBA searches

Survey Period: From first week of April to first week of October

References

Survey References

  • Cummings, K.S. and C.A. Mayer. 1992. Field Guide to Freshwater Mussels of the Midwest. Illinois Natural History Survey Manual 5, Champaign. 194pp.
  • Strayer, D.L. and D.R. Smith. 2003. A Guide to Sampling Freshwater Mussel Populations. American Fisheries Society Monograph 8, Bethesda. 103pp.

Technical References

  • Carman, S.M. 2002. Special Animal Abstract for Alasmidonta viridis (Slippershell mussel). Michigan Natural Features Inventory, Lansing, MI. 3pp.
  • Clarke, A.H. 1981. The Freshwater Molluscs of Canada. National Museum of Natural Science, National Museums of Canada, Ottawa. 446pp.
  • Cummings, K.S. and C.A. Mayer. 1992. Field Guide to Freshwater Mussels of the Midwest. Illinois Natural History Survey Manual 5, Champaign. 194pp.
  • Dillon, R.T. Jr. 2000. The Ecology of Freshwater Molluscs. Cambridge University Press, Cambridge, UK. 509pp.
  • Oesch, R.D. 1984. Missouri Naiades: a Guide to the Mussels of Missouri. Conservation Commision of the State of Missouri, Jefferson City. 270pp.