White Heelsplitter - Lasmigona complanata
The White Heelsplitter is a relatively common mussel in North America, and has been recently introduced into MT. It can
be found as far south as the Tennessee River, throughout the Midwest and Plains States (native in SD, ND) and into southern Canada. The White Heelsplitter prefers pools or sluggish streams with a mud, sand, or fine gravel bottom. Known host fish species include the Common Carp, Green Sunfish, Largemouth Bass, White Crappie, Orangespotted Sunfish and Banded Killfish, all these are introduced or exotic species in Montana.
"Shell elliptical, compressed, mahogany brown; disk roughened only by growth lines; two poorly defined ridges extend from the beaks to the posterior edge and on the posterior slope near the beaks are three or four low folds; beaks not very high, sculptured by 2 or 3 small ridges that are more or less W-shaped; interior pearly white, with two slanting pseudocardinals in one valve and one in the other; lateral teeth broad, low, and not very long; beak cavities shallow; anterior muscle scars broad, deep; posterior scars scarcely showing against the pearly nacre; L. 130, H. 100, D. 32 mm." (La Rocque 1967:191).
Known only from the Lower Milk River and Beaver Creek Creek, a tributary of the Little Missouri River, Wibaux County; an introduced species (Gustafson 1996).
Observations in Montana Natural Heritage Program Database
Number of Observations:
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(Observations spanning multiple months or years are excluded from time charts)
Adult freshwater mussels are mostly sedentary and spend their lives near the area where they first settled as juveniles. They will move short distances (a few meters) during spawning or if prompted by a stimulus such as a water disturbance nearby, exposure due to low water, or seasonal temperature changes. They may burrow into sediments (often doing so in the fall and emerging in the spring) or move away from the area horizontally.
Most dispersal takes places through there host fish, especially the carp.
This mussel has been found to occupy very shallow waters and habitats as deep as 20 feet. The White Heelsplitter prefers pools or sluggish streams with a mud, sand, or fine gravel bottom.Occurs in fine mud in deep pools (Gustafson 1996).
Freshwater mussels are mostly filter-feeders, siphoning in floating particulate organic materials (small plant or animal) from the water column and straining out the particles and expel the strained water. Pedal feeding with the foot muscle has also been observed, mostly in juveniles and younger age-classes.
Known host fish species include the Common Carp, Green Sunfish, Largemouth Bass, White Crappie, Orangespotted Sunfish and Banded Killfish
"The breeding season lasts from at least August to May. Glochidia are subtriangular, with hooks, and measure from 0.28 to 0.34 mm in length and 0.30 to 0.34 mm in height. Known host fish species include the Common Carp, Green Sunfish, Largemouth Bass, White Crappie, Orangespotted Sunfish and Banded Killfish (Clarke 1981:282).
Threats or Limiting Factors
Threats to freshwater mussels and their habitats are thought to include: Pollution, Diversion of rivers for irrigation, hydroelectric and water supply projects, Elimination of natural fish hosts, Eutropification due to agricultural runoff and urbanization
- Literature Cited AboveLegend: View Online Publication
- Clarke, A.H. 1981. The freshwater molluscs of Canada. National Museum of Natural Sciences, National Museums of Canada, Ottawa. 446 pp.
- La Rocque, A. 1967. Pleistocene Mollusca of Ohio. Department of Natural Resources, Division of Geological Survey Bulletin 62, Part 2. 113-365 + 8 plates.
- Miller, K.B. and D.L. Gustafson. 1996. Distribution records of the Odonata of Montana. Bulletin of American Odonatology 3(4):75-88.
- Additional Sources of Information Related to "Mussels / Clams"