Lampsilis siliquoidea

Geographic Range

Fat muckets ( Lampsilis siliquoidea ) are found in the Mississippi River drainage from New York to Minnesota. They occur south to Arkansas but do not occur in the Tennessee or Cumberland River systems. In the St. Lawrence River system, they are found in the Canadian Interior Basin. Fat muckets are also found in Montana and eastern Colorado. In Michigan, they are found in drainages throughout the state, both in the upper and lower peninsulas.

• Biogeographic Regions
• nearctic nearctic
  • native native

Habitat

Although they may be found in various substrates and habitats, from lakes and headwaters to medium-sized rivers, fat muckets are usually found in quiet areas with sandy-mud substrates. Occasionally they are found in riffles, but more often they are found in the water below riffles, or in slowly running water with fine gravel, sand or mud substrates.

• Habitat Regions
• freshwater freshwater

• Aquatic Biomes
• rivers and streams

Physical Description

Fat muckets are up to 12.7 cm long, with an oblong to elliptical shape. Their shell thickness is uniform, and may be thin to thick. This species is sexually dimorphic. Depending on habitat, sex and age, the shell can be compressed or inflated. Their anterior end is rounded, while their posterior end is bluntly pointed in males and truncated in females. Their dorsal margin is straight and their ventral margin is straight or rounded. Their umbos are broad and raised only slightly above the hinge line. Their beak sculpture is fine, with six to ten double-loops. Their periostracum (outer shell layer) is yellow to yellow-brown with green rays. Older specimens tend to be darker and brownish. On the inner shell, their left valve has two pseudo cardinal teeth, which are erect and compressed. Their two lateral teeth are thin, short and slightly curved. Their right valve has one large, erect pseudo cardinal tooth. Anterior to this tooth is a smaller (lamellar) tooth. Their lateral tooth is thin and straight. Their beak cavity is shallow to moderately deep. Although the nacre is white, occasionally it is has a pink or salmon tint and is iridescent posteriorly. In Michigan, fat muckets may be confused with muckets and pocketbooks , although muckets are more compressed and slightly more elliptical and pocketbooks are rounder and have higher umbos.

• Other Physical Features
• ectothermic ectothermic
• heterothermic heterothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• sexes shaped differently

Development

Fertilized eggs are brooded in the marsupia (water tubes) up to 11 months, where they develop into larvae, called glochidia. The glochidia are released into the water where they 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.

• Development - Life Cycle
• metamorphosis metamorphosis

Reproduction

Among unionids , gametogenesis is initiated by increasing water temperatures. Their life cycle includes open fertilization; males release sperm into the water, which is taken in by the females through their respiratory current. Eggs are fertilized internally in the suprabranchial chambers, and pass into water tubes of the gills, where they develop into glochidia.

The age at which fat muckets reach sexual maturity is unknown. Unionids are gonochoristic (sexes are separate) and viviparous. Glochidia, their larval stage, are released live after they are fully developed. Fat muckets are long-term brooders; in Michigan, they are gravid from early August to late July in the Huron River and probably breed in July and early August.

• Key Reproductive Features
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• fertilization fertilization
  • internal internal
• viviparous viviparous

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

Lifespan/Longevity

Their age can be determined by looking at the annual rings on their shell. However, no demographic data has been recorded on this species, although members of family Unionidae generally have about a 10 year lifespan.

Behavior

In general, mussels are rather sedentary, although they may move in response to changing water levels and conditions. It is not thoroughly documented, but mussels may vertically migrate to release glochidia and spawn. Female fat muckets have a mantle flap that resembles a minnow or darter, which lures their host fishes, who chews on the flap and breaks the membrane of the gills. As a result, fishes are infected with glochidia.

• Key Behaviors
• parasite parasite
• motile motile
• sedentary sedentary

Home Range

There is currently no information available about the home range size of fat muckets.

Communication and Perception

Most bivalve sensory organs are located in the middle lobe of their mantle edge. The mussel’s foot includes paired statocysts, which are fluid filled chambers with a solid granule or pellet (a statolity). The statocysts help mussels with georeception and orientation. Mussels are heterothermic, and therefore sensitive and responsive to temperature. In general, unionids may have some form of chemical reception to recognize fish hosts. In genus Lampsilines , mantle flaps are modified to attract potential fish hosts. While fat muckets have a fish lure to attract host fishes, their method of recognition is unknown. Glochidia respond to touch, light and some chemical cues. In general, when touched or introduced to a fluid, they respond by clamping shut.

• Communication Channels
• chemical chemical

• Perception Channels
• visual visual
• tactile tactile
• vibrations vibrations
• chemical chemical

Food Habits

In general, unionids are filter feeders. Mussels use cilia to pump water into their incurrent siphon where food is caught in a mucus lining in the demibranchs. Particles are sorted by their labial palps and are directed to their mouths. Mussels have been cultured on algae, but they may also ingest bacteria, protozoa 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 tissues through phagocytosis.

• Primary Diet
• planktivore planktivore
• detritivore detritivore

• Plant Foods
• algae
• phytoplankton phytoplankton

• Other Foods
• detritus detritus
• microbes

• Foraging Behavior
• filter-feeding filter-feeding

Predation

In general, unionids are preyed upon by muskrats , minks , North American river otters and some birds. Juveniles are probably also consumed by the following fish species: freshwater drums , sheepshead , lake sturgeon , spotted suckers , common redhorses and pumpkinseeds .

Ecosystem Roles

Glochidia will attach to almost any fish, including those that are not suitable hosts. Fat muckets mainly use fish hosts from family Centrarchidae . Infestations and glochidial metamorphosis have been observed on bluegills , black crappies , largemouth bass , walleyes , white crappies and yellow perch . Glochidial metamorphosis has also been observed on longear sunfishes , bluntnose minnows , sand shiners , saugers and smallmouth bass . Their mortality and reproduction is affected by unionicolid mites and monogenic trematodes feeding on their gill and mantle tissues. Likewise, parasitic chironomid larvae may destroy up to half the mussels’ gill.

• Ecosystem Impact
• parasite parasite

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

As of 2012, fat muckets were listed as a species of least concern according to the IUCN Red List of Threatened Species.

Additional Links

Encyclopedia of Life

Contributors

Renee Sherman Mulcrone (author).

References

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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., J. Cordeiro. 2012. " Lampsilis siliquoidea " (On-line). IUCN Red List of Threatened Species. Accessed December 03, 2013 at http://www.iucnredlist.org/details/189448/0 .

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Howard, A. 1922. Experiments in the culture of fresh-water mussels. Bulletin of the Bureau of Fisheries , 38: 63-89.

Lefevre, G., W. Curtis. 1912. Experiments in the artificial propagation of fresh-water mussels. Proceedings of the International Fishery Congress, Washington. Bulletin of the Bureau of Fisheries , 28: 617-626.

Lefevre, G., W. Curtis. 1910. Reproduction and parasitism in the Unionidae . Journal of Experimental Biology , 9: 79-115.

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

O'Dee, S., G. Watters. 2000. New or confirmed host identifications for ten freshwater mussels. Captive Care, and Propagation of Freshwater Mussels Symposium: 77-82.

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

Trdan, R. 1981. Reproductive biology of Lampsilis radiata siliquoidea ( Pelecypoda : Unionidae ). American Midland Naturalist , 106: 243-248.

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

Winhold, L. 2004. "Family Unionidae " (On-line). Animal Diversity Web. Accessed November 25, 2013 at animaldiversity.ummz.umich.edu/accounts/unionidae .

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.