Ligumia recta

Geographic Range

The black sandshell is found throughout the Mississippi drainage from Pennsylvania to Minnesota and south to Oklahoma and Alabama. It also occurs in the Alabama River and St. Lawrence River drainage. In Canada, it is found in the Canadian Interior basin in Lake Winnipeg and the Winnipeg and Red River systems.

In Michigan this species is found in the mainstem and/or lower stretches of rivers in the lower peninsula, generally from the Muskegon River and south, including the Detroit River. Ligumia recta has been recorded from the Menominee and Sturgeon Rivers in the upper peninsula. (Burch, 1975; van der Schalie, 1938)


The black sandshell is found in rivers, lakes, and large streams, usually in riffles or raceways with good current. Substrates it inhabits include sandy mud, firm sand, or gravel.

In the Huron River it was common in large and medium-sized river conditions with sand and gravel bottom in the current. Younger individuals were also found at one site on a fine sand-mud bottom in a backwater area. (Cummings and Mayer, 1992; van der Schalie, 1938; Watters, 1995)

  • Aquatic Biomes
  • rivers and streams

Physical Description

The black sandshell is up to 25 cm (10 inches) long , and is elongate and quadrate in shape. The shell is usually fairly thick, heavy, somewhat inflated and cylindrical. The anterior end is rounded, the posterior end pointed in males, saber-shaped in females. The dorsal margin is straight and the ventral margin is straight to gently curved.

Umbos are low, being raised only slightly above the hinge line. Beaks are situated nearer to the anterior margin than the posterior margin. The beak sculpture has two to three indistinct, double-looped bars.

The periostracum (outer shell layer) is smooth, shiny, dark green or brown. Older specimens tend to be more black. The valves sometimes have visible green rays.

On the inner shell, the left valve has two pseudocardinal teeth, which are long, triangular, serrated and divergent. The two lateral teeth are straight, rough, thin and long. The right valve has one high, notched,triangular pseudocardinal tooth. Anterior to this tooth is occasionally a smaller (lamellar) tooth. The right lateral tooth is also straight, rough, thin and long.

The beak cavity is shallow. The nacre varies, from white, pink, and salmon, and occasionally is purple. At the posterior end it is iridescent.

In Michigan, this species can be confused with the spike. The spike is generally smaller and more compressed. The black sandshell also tends to be shiny and more distinctly rayed. (Cummings and Mayer, 1992; Oesch, 1984; Watters, 1995)

  • Sexual Dimorphism
  • sexes shaped differently
  • Range length
    25 (high) cm
    9.84 (high) in


Fertilized eggs are brooded in the marsupia (water tubes) up to 11 months, where they develop into larvae, called glochidia. The glochidia are then released into the water where they must attach to the gill filaments and/or general body surface of the host fish. After attachment, epithelial tissue from the host fish grows over and encapsulates a glochidium, usually within a few hours. The glochidia then metamorphoses into a juvenile mussel within a few days or weeks. After metamorphosis, the juvenile is sloughed off as a free-living organism. Juveniles are found in the substrate where they develop into adults. (Arey, 1921; Lefevre and Curtis, 1910)


Age to sexual maturity for this species is unknown. Unionids are gonochoristic (sexes are separate) and viviparous. The glochidia, which are the larval stage of the mussels, are released live from the female after they are fully developed.

In general, gametogenesis in unionids is initiated by increasing water temperatures. The general life cycle of a unionid, includes open fertilization. Males release sperm into the water, which is taken in by the females through their respiratory current. The eggs are internally fertilized in the suprabranchial chambers, then pass into water tubes of the gills, where they develop into glochidia.

Ligumia recta is a long-term brooder. In the Huron River in Michigan, it was gravid from mid-May to late August to mid-July. In Michigan L. recta probably spawns from mid-July through August. (Lefevre and Curtis, 1912; Watters, 1995)

  • Breeding interval
    The black sandshell breeds once in the warmer months of the year.
  • Breeding season
    In Michigan, the breeding season is probably mid-July through August.
  • Range gestation period
    11 (high) months

Females brood fertilized eggs in their marsupial pouch. The fertilized eggs develop into glochidia. There is no parental investment after the female releases the glochidia.

  • Parental Investment
  • pre-fertilization
    • provisioning
  • pre-hatching/birth
    • provisioning
      • female


The age of mussels can be determined by looking at annual rings on the shell. However, no demographic data on this species has been recorded.


Mussels in general are rather sedentary, although they may move in response to changing water levels and conditions. Although not thoroughly documented, the mussels may vertically migrate to release glochidia and spawn. (Oesch, 1984)

Communication and Perception

The middle lobe of the mantle edge has most of a bivalve's sensory organs. Paired statocysts, which are fluid filled chambers with a solid granule or pellet (a statolity) are in the mussel's foot. The statocysts help the mussel with georeception, or orientation.

Mussels are heterothermic, and therefore are sensitive and responsive to temperature.

Unionids in general may have some form of chemical reception to recognize fish hosts. Mantle flaps in the lampsilines are modified to attract potential fish hosts. How the black sandshell attracts and/or recognizes a fish host is unknown.

Glochidia respond to touch, light and some chemical cues. In general, when touched or a fluid is introduced, they will respond by clamping shut. (Arey, 1921; Brusca and Brusca, 2003; Watters, 1995)

Food Habits

In general, unionids are filter feeders. The mussels use cilia to pump water into the incurrent siphon where food is caught in a mucus lining in the demibranchs. Particles are sorted by the labial palps and then directed to the mouth. Mussels have been cultured on algae, but they may also ingest bacteria, protozoans and other organic particles.

The parasitic glochidial stage absorbs blood and nutrients from hosts after attachment. Mantle cells within the glochidia feed off of the host’s tissue through phagocytocis. (Arey, 1921; Meglitsch and Schram, 1991; Watters, 1995)


Unionids in general are preyed upon by muskrats, raccoons, minks, otters, and some birds. Juveniles are probably also fed upon by freshwater drum, sheepshead, lake sturgeon, spotted suckers, redhorses, and pumpkinseeds.

Unionid mortality and reproduction is affected by unionicolid mites and monogenic trematodes feeding on gill and mantle tissue. Parasitic chironomid larvae may destroy up to half the mussel gill. (Cummings and Mayer, 1992; Watters, 1995)

Ecosystem Roles

Fish hosts are determined by looking at both lab metamorphosis and natural infestations. Looking at both is necessary, as lab transformations from glochidia to juvenile may occur, but the mussel may not actually infect a particular species in a natural situation. Natural infestations may also be found, but glochidia will attach to almost any fish, including those that are not suitable hosts. Lab transformations involve isolating one particular fish species and introducing glochidia either into the fish tank or directly inoculating the fish gills with glochidia. Tanks are monitored and if juveniles are later found the fish species is considered a suitable host.

Metamorphosis of glochidia and natural glochidial infestations of Ligumia recta have been observed for bluegill and white crappie.

In lab trials, glochidia have metamorphosed on several other fish, including the banded killifish, white perch, central stoneroller, redfin shiner, rosyface shiner, redbreast sunfish, green sunfish, longear sunfish, orangespotted sunfish, pumpkinseed, rock bass, largemouth bass, walleye and yellow perch. (Coker, et al., 1921; Cummings and Watters, 2004; Hove, M.C., J.E. Kurth, et al., 1998; Lefevre and Curtis, 1912; Steg and Neves, 1997; Watters, et al., 1999; Young, 1911)

Species Used as Host

Economic Importance for Humans: Positive

Mussels are ecological indicators. Their presence in a water body usually indicates good water quality.

Economic Importance for Humans: Negative

There are no significant negative impacts of mussels on humans.

Conservation Status

Ligumia recta is listed as Endangered in Vermont, Threatened in Illinois and Virginia, and Special Concern in Minnesota. The IUCN Red List considers this species Lower Risk, Nearly Threatened. (Hove, 2004)


Renee Sherman Mulcrone (author).



living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.


uses smells or other chemicals to communicate


an animal that mainly eats decomposed plants and/or animals


particles of organic material from dead and decomposing organisms. Detritus is the result of the activity of decomposers (organisms that decompose organic material).


animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature


union of egg and spermatozoan


a method of feeding where small food particles are filtered from the surrounding water by various mechanisms. Used mainly by aquatic invertebrates, especially plankton, but also by baleen whales.


mainly lives in water that is not salty.


having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

internal fertilization

fertilization takes place within the female's body


A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.


having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.


an organism that obtains nutrients from other organisms in a harmful way that doesn't cause immediate death


photosynthetic or plant constituent of plankton; mainly unicellular algae. (Compare to zooplankton.)


an animal that mainly eats plankton

seasonal breeding

breeding is confined to a particular season


remains in the same area


reproduction that includes combining the genetic contribution of two individuals, a male and a female


uses touch to communicate


movements of a hard surface that are produced by animals as signals to others


uses sight to communicate


reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.


Arey, L. 1921. An experimental study on glochidia and the factors underlying encystment. J. Exp. Zool., 33: 463-499.

Brusca, R., G. Brusca. 2003. Invertebrates. Sunderland, Massachusetts: Sinauer Associates, Inc..

Burch, J. 1975. Freshwater unionacean clams (Mollusca: Pelecypoda) of North America. Hamburg, Michigan: Malacological Publications.

Coker, A., R. Shira, H. Clark, A. Howard. 1921. Natural history and propagation of fresh-water mussels. Bulletin of the Bureau of Fisheries, 37: 77-181.

Cummings, K., C. Mayer. 1992. Field guide to freshwater mussels of the Midwest. Champaign, Illinois: Illinois Natural History Survey Manual 5. Accessed August 25, 2005 at

Cummings, K., G. Watters. 2004. "Molluscs Division of the Museum of Biological Diversity at the Ohio State University" (On-line). Accessed September 27, 2005 at

Hill, D. 1986. Cumberlandian Mollusks Conservation Program, activity 3: Identification of fish hosts. Knoxville: Office of Natural Resources and Economic Development, Tennessee Valley Authority.

Hove, M.C., J.E. Kurth, , D.J. Heath, R.L. Benjamin, M.B. Endris, R.L. Kenyon, R. Kenyon, Kapuscinski, A.R., Hillegass, K.R.. 1998. Hosts and host atracting behaviors of five upper Mississippi River mussels. Abstracts, World Congress of Malacology, Washington, DC: 159.

Hove, M. 2004. "Links to each state's listed freshwater mussels, invertebrates, or fauna" (On-line). Accessed September 21, 2005 at

Lefevre, G., W. Curtis. 1912. Experiments in the artificial propagation of fresh-water mussels. Proc. Internat. Fishery Congress, Washington. Bull. Bur. Fisheries, 28: 617-626.

Lefevre, G., W. Curtis. 1910. Reproduction and parasitism in the Unionidae. J. Expt. Biol., 9: 79-115.

Meglitsch, P., F. Schram. 1991. Invertebrate Zoology, Third Edition. New York, NY: Oxford University Press, Inc.

Oesch, R. 1984. Missouri naiades, a guide to the mussels of Missouri. Jefferson City, Missouri: Missouri Department of Conservation.

Steg, M., R. Neves. 1997. Fish host identification for Virginia listed unionids in the upper Tennessee River drainage. Triannual unionid report, 13: 34. Accessed October 04, 2005 at

Watters, G. 1995. A guide to the freshwater mussels of Ohio. Columbus, Ohio: Ohio Department of Natural Resources.

Watters, G., S. O'Dee, S. Chordas, D. Glover. 1999. Seven potential hosts for Ligumia recta (Lamarck, 1819). Trannual unionid report, 18: 5. Accessed October 04, 2005 at

Young, D. 1911. The implantation of the glochidium on the fish. Univerity of Missouri Bulletin Science Series, 2: 1-20.

van der Schalie, H. 1938. The naiad fauna of the Huron River, in southeastern Michigan. Miscellaneous Publications of the Museum of Zoology, University of Michigan, 40: 1-83.