Lampsilis cardium

Geographic Range

The pocketbook is found in the Mississippi River drainage, St. Lawrence drainage and southern drainages to Hudson Bay. It occurs west from eastern Manitoba south to nothern Oklahoma, east to eastern Tennessee and north to Nova Scotia.

In Michigan the pocketbook is found throughout the lower peninsula, and in the upper peninsula, from Marquette and Dickinson County to the east. Collection records do not show it in Alger, Schoolcraft and Chippewa counties, although it still may be in water bodies there. (Oesch, 1984; Parmalee, 1967)


The pocketbook is found in lakes, streams and rivers, in mud, sand, and gravel. In the Huron River, they mainly occupied areas above and below riffles in sand or gravel. In the Huron’s lakes it was found mainly on solid shoals of sand, gravel or marl. (Cummings and Mayer, 1992; van der Schalie, 1938; Watters, 1995)

  • Aquatic Biomes
  • rivers and streams

Physical Description

The pocketbook is up to 17.8 cm (7 inches) long , and is round or quadrate in shape. The shell is thinner in young individuals, thicker in older individuals, and inflated. This species is sexually dimorphic. The anterior end is rounded and the posterior end gently rounded in females and bluntly pointed in males. The dorsal margin is straight to gently curved and the ventral margin is broadly rounded.

Umbos are broad, elevated above the hinge line, and turned forward. The beak sculpture has four or five elevated ridges and may be double-looped.

The periostracum (outer shell layer) is smooth, yellow to yellow-green with green rays, although sometimes rays are absent.

On the inner shell, the left valve has two pseudocardinal teeth, which are erect, compressed, and striated. The posterior tooth is usually short and triangular. The two lateral teeth are short, thin and striated. The right valve has one erect and stout pseudocardinal tooth with another erect compressed tooth anteriorly. The one lateral tooth is high, thin and short.

The beak cavity is broad and deep. The nacre is white and iridescent posteriorly.

In Michigan, this species can be confused with the mucket, fat mucket, or wavy-rayed lampmussel. The mucket is more compressed. The fat mucket is more elongated. The wavy-rayed lampmussel in general has wavy rays, and because it is smaller than the pocketbook, the growth lines will be closer together. (Cummings and Mayer, 1992; Oesch, 1984; Watters, 1995)

  • Sexual Dimorphism
  • sexes shaped differently
  • Range length
    17.8 (high) cm
    7.01 (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.

Lampsilis cardium is a long-term brooder. In the Huron River in Michigan, the pocketbook was gravid from early August to mid-July. It probably breeds in June and July in Michigan. (Lefevre and Curtis, 1912; Watters, 1995)

  • Breeding interval
    The pocketbook breeds once in the warmer months of the year.
  • Breeding season
    In Michigan, the breeding season is probably June to July.
  • 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.

A female Lampsilis cardium has a distinct mantle flap which resembles a minnow or darter. The mimic fish lures its host fish,which chews on the flap and breaks the membrane of the gills. As a result, the fish is infected with glochidia. (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. Lampsilis cardium has a mantle flap resembling a minnow or darter to attrach host fish.

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. (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 transformations 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.

The main fish hosts for this species are probably centrarchids. Both natural infections and lab metamorphosis has been observed for the white crappie. In lab trials, Lampsilis cardium metamorphosed on bluegill, green sunfish, largemouth bass, and smallmouth bass. Lab transformations were also observed for the banded killifish and walleye. (Coker, et al., 1921; Cummings and Watters, 2004; Lefevre and Curtis, 1912; Reuling, 1919; Waller, et al., 1985; Watters, 1996)

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

Lampsilis cardium currently does not have any individual state conservation status. However, it is on the IUCN Red List as Lower Risk, Near Threatened.

Other Comments

Lampsilis cardium was formerly known as Lampsilis ovata and Lampsilis ovata.


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, R., A. 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. "Mussel/Host Data Base" (On-line). Molluscs Division of the Museum of Biological Diversity at the Ohio State University. Accessed September 26, 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.

Parmalee, P. 1967. The fresh-water mussels of Illinois. Springfield, Illinois: Illinois State Museum Popular Science Series 8. 108 pp.

Reuling, F. 1919. Acquired immunity to an animal parasite. Journal of Infectuous Diseases, 24: 337-346.

Waller, D., L. Holland-Bartels, L. Mitchell, T. Kammer. 1985. Artificial infestation of largemouth bass and walleye with glochidia of Lampsilis ventricosa (Pelecypoda: Unionidae). Freshwater Invertebrate Biology, 4: 152-153.

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

Watters, G. 1996. New hosts for Lampsilis cardium. Triannual Unionid Report, 9: 8. Accessed October 04, 2005 at

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.