Plants and Animals

Lasmigona compressa Creek heelsplitter

species photo
Kurt Stepnitz

Key Characteristics

The Creek heelsplitter has a small dorsal wing that extends slightly above the hinge line. Its outline is wedge shaped at the posterior end, coming to a blunt squared-off point at the ventral-posterior corner. Maximum length is 11 cm and this mussel’s life span is around 13 years. Creek heelsplitter is quite compressed. Beak sculpture is three to four somewhat ‘W’ shaped ridges. The beak is not inflated, and the beak cavity is very shallow and broad. Color is tan to yellow with numerous narrow and broad green rays that can sometimes cover more than 80% of the shell surface. The cardinal teeth are relatively small, and the lateral teeth are thin. Nacre color is white, occasionally tinged with salmon or green.

Status and Rank

US Status: No Status/Not Listed
State Status: SC - Special Concern (rare or uncertain; not legally protected)
Global Rank: G5 - Secure
State Rank: S3 - Vulnerable


CountyNumber of OccurrencesYear Last Observed
Alger 1 2013
Allegan 5 2018
Alpena 2 1962
Antrim 1 1938
Barry 4 2018
Benzie 1 1949
Berrien 4 2009
Branch 1 1942
Calhoun 7 2019
Cass 2 1923
Cheboygan 2 1914
Chippewa 1 1938
Clare 5 1966
Clinton 5 2010
Crawford 3 1939
Delta 1 2013
Dickinson 10 2009
Eaton 5 2018
Emmet 3 1945
Gladwin 1 1926
Grand Traverse 2 1949
Gratiot 1 1934
Hillsdale 8 2022
Ingham 4 1937
Ionia 8 2021
Iron 5 2019
Isabella 4 2015
Jackson 8 2017
Kalamazoo 5 2022
Kalkaska 4 2012
Kent 12 2017
Lake 1 Historical
Lapeer 1 Historical
Leelanau 1 2019
Lenawee 6 2016
Livingston 6 1965
Mackinac 1 1941
Macomb 4 2011
Manistee 1 1949
Marquette 1 1980
Mason 1 2004
Mecosta 1 1934
Menominee 6 2009
Midland 2 2011
Missaukee 1 1926
Monroe 4 2017
Montcalm 4 2015
Montmorency 2 1945
Muskegon 1 Historical
Newaygo 4 1949
Oakland 7 2016
Oceana 1 1934
Ogemaw 2 1946
Ontonagon 1 2018
Osceola 2 2022
Oscoda 2 2013
Otsego 2 1967
Ottawa 4 1934
Presque Isle 2 1952
Saginaw 3 2011
Sanilac 5 2009
Schoolcraft 2 2018
Shiawassee 3 1934
St. Clair 14 2020
St. Joseph 3 1969
Tuscola 2 1937
Van Buren 5 2009
Washtenaw 6 1978
Wayne 5 2017
Wexford 1 2016

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 creek heelsplitter is found in creeks and small rivers in a variety of substrates.

Natural Community Types

  • Headwater stream (1st-2nd order), riffle
  • Headwater stream (1st-2nd order), pool
  • Headwater stream (1st-2nd order), run
  • Mainstem stream (3rd-4th order), pool
  • 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 creek heelsplitter is at risk from point source pollution, non-point source pollution, alteration of natural stream flow patterns, barriers to host fish passage, direct alteration of habitat, and invasive zebra mussels.

Maintain riparian buffers along streams and promote land conservation programs to help reduce excessive erosion, sedimentation, and nutrient input from non-point sources. Maintaining integrity of headwater streams and wetlands is especially important for creek heelsplitters since they are strongly associated with small rivers and creeks. Improve passage for fish by removing unnecessary dams and upgrading poor stream/road crossings such as culverts that are too small or are perched. Creek heelsplitter and other native mussels require fish hosts to complete their life cycle and rely on fish passage to travel to new habitats and facilitate gene flow among mussel populations. Avoid dredging, channelization, and other in-stream impacts whenever possible. Limit or eliminate point source discharges of ammonia, chloride, sulfate, heavy metals, and other substances toxic to native mussels.

Since the range of creek heelsplitter is typically restricted to smaller sized streams with little or no boat traffic, this species has not been impacted by zebra mussels as much as most other native mussel species. Still, the spread of zebra mussels into Michigan’s streams and lakes remains a serious threat. Avoid the transport of water or aquatic plants – which can contain zebra mussel larvae – from one body of water to another while boating, fishing, and hunting. Wash boats, trailers, and gear, and let them dry over night to reduce the potential for spreading zebra mussels.

Active Period

Gravid from first week of August to second week of September

Survey Methods

In water shallower than waist deep, wading with a glass bottom bucket and, if water quality is good, swimming with a snorkel and mask are effective ways to search for creek heelsplitter. SCUBA or other dive gear is required for greater water depths. Stream substrate should be searched both visually and tactilely, by sweeping the fingers through the substrate. Creek heelsplitter can be completely buried at times and difficult to detect visually. Empty shells may be found along riverbanks and occasionally in shell middens created by predators such as muskrats. A scientific collector’s permit is required to possess live native mussels shell or live individuals. Mussel surveys related to permitted projects in rivers and lakes should follow the Michigan Freshwater Mussel Survey Protocols and Relocation Procedures. Federal and/or state threatened and endangered species permits must be obtained prior to surveying for native mussels within waterbodies likely to support these species. Refer to the Mussel Map Viewer available on MNFI’s website.

Glass-bottom bucket less than waist deep water

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

SCUBA greater than waist deep water

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

Survey Method Comment: Surface supplied diving may be appropriate in some cases.

Snorkeling searches

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

Survey Method Comment: Use this method only when water quality and conditions are safe for swimming.


Survey References

  • Hanshue, S., J. Rathbun, P. Badra, J. Bettaso, B. Hosler, J. Pruden, and J. Grabarkiewicz. 2019. Michigan Freshwater Mussel Survey Protocols and Relocation Procedures [for rivers], Version 2. Michigan Department of Natural Resources.
  • Metcalfe-Smith, J., A. MacKenzie, I. Carmichael, and D. McGoldrick. 2005. Photo Field Guide to the Freshwater Mussels of Ontario. St. Thomas Field Naturalist Club Inc, 60 pp.
  • Mulcrone, R.S., and J.E. Rathbun. 2018. Field Guide to the Freshwater Mussels of Michigan.  Michigan Department of Natural Resources, 59 pp.
  • Watters, G. Thomas, Michael A. Hoggarth, and David H. Stansbery. 2009. The Freshwater Mussels of Ohio. The Ohio State University Press, Columbus. 421 pp.

Technical References

  • Blevins, E., L. McMullen, S. Jepsen, M. Blackburn., A. Code, and S.H. Black. 2017. Conserving the Gems of Our Waters: Best Management Practices for Protecting Native Western Freshwater Mussels During Aquatic and Riparian Restoration, Construction, and Land Management Projects and Activities. 108 pp. Portland, OR: The Xerces Society for Invertebrate Conservation.
  • Brim-Box, J., and J. Mossa. 1999. Sediment, land use, and freshwater mussels: Prospects and problems. Journal of the North American Benthological Society 18: 99-117.
  • Colvin, S.A.R., S.M.P. Sullivan, P.D. Shirey, R.W. Colvin, K.O. Winemiller, R.M. Hughes, K.D. Fausch, D.M. Infante, J.D. Olden, K.R. Bestgen, R.J. Danehy, and L. Eby. 2019. Headwater streams and wetlands are critical for sustaining fish, fisheries, and ecosystem services. American Fisheries Society Special Report. Fisheries 44: 73-91.
  • Freshwater Mollusk Conservation Society. 2016. A national strategy for the conservation of native freshwater mollusks. Freshwater Mollusk Biology and Conservation 19: 1-21.
  • Haag, W.R. 2012. North American Freshwater Mussels: Natural History, Ecology, and Conservation. Cambridge University Press, New York, 505 pp.
  • Strayer, D.L. and D.R. Smith. 2003. A Guide to Sampling Freshwater Mussel Populations. American Fisheries Society Monograph 8, Bethesda. 103pp.
  • Watters, G.T. 1996. Small dams as barriers to freshwater mussels (Bivalvia, Unionoida) and their hosts. Biological Conservation 75: 79-85.