Plants and Animals

Cyclonaias tuberculata Purple wartyback

species photo
species photo

Key Characteristics

The purple wartyback has a roughly circular shell (to 5 inches) with numerous bumps covering about ¾ of the outside. The beak sculpture consists of numerous wavy ridges and the cavity is very deep. They have very heavy, well developed cardinal teeth and lateral teeth along the hinge. The thick and heavy shell is yellowish brown or green brown, becoming dark brown in older individuals. Nacre color ranges from white with a hint of purple to deep purple.

Status and Rank

US Status:
State Status: T - Threatened (legally protected)
Global Rank: G5 - Secure
State Rank: S2 - Imperiled

Occurrences

CountyNumber of OccurrencesYear Last Observed
Allegan32000
Bay11908
Berrien42001
Cass11940
Dickinson1
Eaton11996
Ionia72017
Jackson32010
Kalamazoo11981
Kent122017
Lenawee21925
Macomb11933
Menominee32011
Monroe112017
Ottawa11959
St. Clair12011
St. Joseph42006
Washtenaw112010
Wayne112006

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 Purple wartyback is found in medium to large rivers with gravel or mixed sand and gravel substrates.

Specific Habitat Needs

Gravel substrate needed in: Mainstem Stream (3rd-4th order), RunMainstem Stream (3rd-4th order), RiffleRiver (5th-6th order), RunRiver (5th-6th order), Riffle.

Natural Community Types

  • Mainstem stream (3rd-4th order), run
  • Mainstem stream (3rd-4th order), riffle
  • River (5th-6th order), run
  • River (5th-6th 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

Like other mussels, threats are varied and include: habitat degradation, poor water quality, flow alterations, water temperature changes, heavy metals, organic pollution, sedimentation, and siltation. Maintenance or establishment of vegetated riparian buffers can help protect mussel habitats from many of these threats. Control of zebra mussels is critical to preserving native mussels. As with all mussels, fish host requirements also need to be considered.

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

  • Badra, P.J. 2004. Special Animal Abstract for Cyclonaias tuberculata (Purple wartyback). Michigan Natural Features Inventory, Lansing, MI. 4pp.
  • Badra, P.J. and R.R. Goforth. 2002. Surveys of Native Freshwater Mussels in the Lower Reaches of Great Lakes Tributary Rivers in Michigan. Report number MNFI 2002-03. Report to Michigan Department Of Environmental Quality, Coastal Zone Management Unit, Lansing, MI. 39pp.
  • Box, J.B. and J. Mossa. 1999. Sediment, land use, and freshwater mussels: prospects and problems. Journal of the North American Benthological Society 18:99-117.
  • 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.