Lampsilis cariosa

Geographic Range

Lampsilis cariosa, also known as the yellow lampmussel, is a freshwater mussel native to eastern North America, spanning from Georgia in the United States to Nova Scotia in Canada. (Kelly and Rhymer, 2005; Sabine, et al., 2004)


Lampsilis cariosa is found primarily in larger streams and rivers with a moderate-to-fast stream flow, especially in riffles. The yellow lampmussel is most common in rivers with drainages exceeding 1200 km^2. The mussel lives mostly buried within the streambed substrate, and favors a level sand and gravel substrate or sands downstream from large rocks and boulders. Though less common, L. cariosa has also been found in lakes. ("Management Plan for the Yellow Lampmussel (Lampsilis cariosa) in Canada - Proposed", 2009; American Museum of Natural History, 2013; Jirka and Strayer, 1997; Sabine, et al., 2004; Strayer, 1993)

  • Aquatic Biomes
  • benthic
  • lakes and ponds
  • rivers and streams

Physical Description

The yellow lampmussel is a nearly egg-shaped mussel with a rounded edge, though adult male mussels appear more elongated than females. Individuals average 75 mm in length, but the largest individuals may grow to 130 mm and have a shell up to 4.0 mm thick. Lampsilis cariosa, like other bivalves, has two valves, or shells, that connect at the umbo. The umbo is the oldest part of the mussel, and it is moderately swollen in thickness and somewhat double-looped in pattern. The outermost layer of the shell, or periostracum, is clear and glossy yellow in color. As individuals age, the shiny yellowish color darkens. Fine green rays are uncommon in L. cariosa, but when present are clearly defined and found only on the posterior angle of the shell. The yellow lampmussel may be confused with other Lampsilis species, such as Lampsilis ovata or Leptodea ochracea, but the presence of green rays widespread across the valves on these species traditionally acts as a means for distinguishing them from L. cariosa.

On the inside of the shell, the inner surface, or nacre, of the yellow lampmussel is glossy white or bluish-white in color. The mussel has hinge teeth that assist in keeping the two valves in alignment at the anterior-dorsal region of the shell. The left valve has two pseudocardinal teeth, and the right valve has one. These teeth, in addition to the mussel's lateral teeth, are distinct and prominent, but they vary in shape.

Mantle tissue, or the soft tissue lining the inside of the mussel, is smooth, gray, and has darker markings of streaks or dots. Females of L. cariosa have a well-developed mantle, which is displayed externally from the mussel to act as a lure for fish. Females' mantle tissue is pigmented and flap-like and has additional coloring and the presence of dark eyespot-like markings. ("Management Plan for the Yellow Lampmussel (Lampsilis cariosa) in Canada - Proposed", 2009; American Museum of Natural History, 2013; "Mussel glossary", 2006; Jirka and Strayer, 1997; The University of Georgia Museum of Natural History, 2008; "Freshwater mussels of the upper Mississippi River system", 2006)

  • Sexual Dimorphism
  • sexes shaped differently
  • Range length
    130 (high) mm
    5.12 (high) in
  • Average length
    100 mm
    3.94 in


Lampsilis cariosa has an intricate life cycle that begins with a parasitic larval stage, characteristic of unionid bivalves, known as a glochidium (pl. glochidia). Composed of chitinous valves, the glochidium resembles a miniature version of the adult mussel and is typically 0.3 mm or smaller. Glochidia are released into the water column by a female in response to the female's mantle lure being struck by a potential host fish, either a white perch (Morone americana) or a yellow perch (Perca flavescens). Upon release, the glochidia attach to the host fish by clamping their two valves tightly together around its tissue and digesting the tissue between the valves. Once attached, the fish host's tissues continue to grow around the glochidium in response to its tissue damage which causes encystment of the parasitic larvae. While encysted, the glochidia undergo metamorphosis to the juvenile stage. At the end of its parasitic period, the length of which is not specified in the literature, the newly developed juvenile excysts from the host fish and falls to the substrate where it then burrows into the sediment and grows into an adult mussel. ("Management Plan for the Yellow Lampmussel (Lampsilis cariosa) in Canada - Proposed", 2009; Arey, 1932; Kelly and Rhymer, 2005; Williams, et al., 2008)


The yellow lampmussel is dioecious and reproduces through sexual reproduction, including open fertilization. During the summer months, male Lampsilis cariosa release their sperm into the water column to be taken in by females through their siphon so as to fertilize their eggs. Water temperature is likely an important cue for reproduction to occur, and gametogenesis in freshwater mussels has been observed to cease in response to cold water temperatures. ("Management Plan for the Yellow Lampmussel (Lampsilis cariosa) in Canada - Proposed", 2009; The University of Georgia Museum of Natural History, 2008; "Freshwater mussels of the upper Mississippi River system", 2006)

After fertilization, the eggs develop within the female mussel's marsupium, or brood pouch, into parasitic glochidia. Due their parasitic nature, L. cariosa glochidia require a host fish of either the white or yellow perch, upon which the glochidia attach and continue to mature into adults once released from the gravid female. In order to attract a potential host fish, females extend their modified mantle flap. This mantle tissue has distinctive markings and pigmentation such as an ‘eyespot' which cause it to resemble a small fish or minnow and acts as a fish lure to increase the probability of contact between mantle flap and fish. Once this lure is struck by a predatory fish, the fully matured glochidia are released by the female and attach to the fish's gill or fin tissue.

The age at sexual maturity for L. cariosa is unknown, as is the precise timing of fertilization, larval maturation and glochidia release; however, most literature cites freshwater mussels as beginning sexual reproduction between three and five years of age. ("Management Plan for the Yellow Lampmussel (Lampsilis cariosa) in Canada - Proposed", 2009; The University of Georgia Museum of Natural History, 2008; Williams, et al., 2008)

  • Breeding season
    Breeding takes place in the summer.
  • Range age at sexual or reproductive maturity (female)
    3 to 5 years
  • Range age at sexual or reproductive maturity (male)
    3 to 5 years

Fertilized eggs remain inside the female yellow lampmussel from summer until spring as they develop into parasitic glochidia before being released into the water column. After release, there is no further parental care. (The University of Georgia Museum of Natural History, 2008)

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


In the Sydney River in Nova Scotia, Canada, the average lifespan is recorded as 7.8 years of age (± 2.7 years). Information for the lifespan of Lampsilis cariosa in the rest of its range is not available, but it is likely similar. The longest known lifespan for the yellow lampmussel is 17 years. ("Management Plan for the Yellow Lampmussel (Lampsilis cariosa) in Canada - Proposed", 2009; American Museum of Natural History, 2013)

  • Range lifespan
    Status: wild
    17 (high) years
  • Average lifespan
    Status: wild
    7.8 years


Freshwater mussels have a muscular foot that allows them to burrow and anchor into the substrate at the bottom of their habitat. This foot allows for some mobility within the sediment, which enables individuals of L. cariosa to reposition themselves for feeding or to accommodate seasonal water level fluctuations. For most of their lives, only the posterior end of the mussel is exposed, and the individual remains sedentary within the substrate. The primary means of dispersal for Lampsilis cariosa is during the parasitic glochidial stage when larvae are suspended in the water column and attach themselves to host fish. ("Management Plan for the Yellow Lampmussel (Lampsilis cariosa) in Canada - Proposed", 2009; Williams, et al., 2008)

Communication and Perception

The mussel's long, muscular foot, which anchors it to the stream bottom, will be withdrawn back into the individual and will clamp shut in response to cues such as physical contact or being removed from the sediment. Freshwater mussels are also responsive to shadows. Release of glochidia into the water column by Lampsilis cariosa females is triggered by physical contact between host fish and mantle fish lure. The mantle fish lure resembles a small fish typically targeted by the host fish so as to increase the likelihood of contact. No additional information is cited in the literature for communication or perception by L. cariosa or mechanisms through which these interactions occur. ("Management Plan for the Yellow Lampmussel (Lampsilis cariosa) in Canada - Proposed", 2009; Bruenderman, et al., 2002)

  • Other Communication Modes
  • mimicry

Food Habits

Lampsilis cariosa is a filter feeder that helps to remove toxins, detritus, and microorganisms from both the water column and sediment as it feeds. Water is taken in by the mussel's incurrent siphon and washes over its gills, at which point oxygen, food, and other particles are removed. Algae and small bits of decaying waste are ingested as food, as is other fine organic particulate matter. Not many specifics are known about freshwater mussel food and feeding habits. Waste from feeding is released through the excurrent siphon as pseudofeces, which provides a food source for other freshwater organisms. ("Management Plan for the Yellow Lampmussel (Lampsilis cariosa) in Canada - Proposed", 2009; Bruenderman, et al., 2002; Williams, et al., 2008)


The larval and adult stages of Lampsilis cariosa are subjected to different predators. Juvenile and larval yellow lampmussels are potential prey for ducks, herons, fish, and invertebrates, whereas older, larger mussels are prey to muskrats, otters, and raccoons. Muskrats are a predator of L. cariosa found throughout its geographic range and can potentially threaten a population's viability. However, muskrats tend to prefer thinner-shelled mussel species over L. cariosa. Because freshwater mussels withdraw their muscular foot inside their shell when removed from the substrate in which they are burrowed and quickly clamp shut, the thick shell of L. cariosa acts as a defensive mechanism and/or deterrent to predators. ("Management Plan for the Yellow Lampmussel (Lampsilis cariosa) in Canada - Proposed", 2009; Bruenderman, et al., 2002; Kurth, 2007; Sabine, et al., 2004)

Ecosystem Roles

Because Lampsilis cariosa, like other freshwater mussels, is a suspension feeder, it filters the water supply and improves water quality. Additionally, the pseudofeces it releases provides food for other freshwater organisms. The yellow lampmussel serves a prey to a variety of other animals, including fish, water fowl, and medium sized mammals such as otters and muskrats. The white perch (Morone americana) and yellow perch (Perca flavescens) are critical during the life cycle of Lampsilis cariosa because they serve as hosts for the parasitic glochidia, which must attach to the host fish for metamorphosis into a juvenile to occur. ("Management Plan for the Yellow Lampmussel (Lampsilis cariosa) in Canada - Proposed", 2009; Kelly and Rhymer, 2005)

Species Used as Host

Economic Importance for Humans: Positive

Historically, freshwater mussels were harvested and consumed by Native Americans. From the mid-to-late-1800s, mussels were harvested for their pearls or for their shells, which could be used to produce buttons. Freshwater mussels such as Lampsilis cariosa act as ecological indicator species due to their sensitivity to environmental changes. (Mock, et al., 2004; Williams, et al., 2008)

  • Positive Impacts
  • food
  • body parts are source of valuable material
  • research and education

Economic Importance for Humans: Negative

There are no know adverse effects of Lampsilis cariosa on humans.

Conservation Status

The yellow lampmussel is listed as an endangered species and is threatened by habitat destruction, declining water quality, damming and channelization of waterways, runoff from farms, predation, and non-native or invasive species introduction. Due to their limited mobility, freshwater mussels are particularly vulnerable.

Invasive species such as the zebra mussel (Dreissena polymorpha) and the Asian clam (Corbicula fluminea) are potentially severe threats for the native yellow lampmussel. These invasive species form colonies in large numbers and may cause the death of L. cariosa populations.

Because Lampsilis cariosa requires a specific host fish for its life cycle, many conservation efforts focus on protecting the host fish in addition to the mussel itself. Any obstacle that redirects natural water flow may inhibit host fish movement and therefore glochidia dispersal for L. cariosa. Some efforts to preserve the species as a result of dam construction have included translocating individuals elsewhere within the waterway; however, individuals do not always survive the translocation process.

Prohibition of the killing of fish and mussels aside from the act of fishing, preventing harmful activities to the habitat itself (including alteration, disruption and destruction), and regulating the usage/deposition of chemicals or substances that may impact water quality are all steps that have been taken to help preserve the species. ("Management Plan for the Yellow Lampmussel (Lampsilis cariosa) in Canada - Proposed", 2009; Bogan, 1996; Kurth, 2007; Williams, et al., 1993)


Yesenia M Werner (author), The College of New Jersey, Keith Pecor (editor), The College of New Jersey, Angela Miner (editor), Animal Diversity Web Staff.



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


Referring to an animal that lives on or near the bottom of a body of water. Also an aquatic biome consisting of the ocean bottom below the pelagic and coastal zones. Bottom habitats in the very deepest oceans (below 9000 m) are sometimes referred to as the abyssal zone. see also oceanic vent.

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.


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.


A substance that provides both nutrients and energy to a living thing.


mainly lives in water that is not salty.


An animal that eats mainly plants or parts of plants.


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.


imitates a communication signal or appearance of another kind of organism


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.


reproduction in which eggs develop within the maternal body without additional nourishment from the parent and hatch within the parent or immediately after laying.


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.)

polarized light

light waves that are oriented in particular direction. For example, light reflected off of water has waves vibrating horizontally. Some animals, such as bees, can detect which way light is polarized and use that information. People cannot, unless they use special equipment.


the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

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


lives alone


uses touch to communicate


that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).


United States Fish and Wildlife Service. 2006. "Freshwater mussels of the upper Mississippi River system" (On-line). Accessed October 01, 2013 at

Fisheries and Oceans Canada. Management Plan for the Yellow Lampmussel (Lampsilis cariosa) in Canada - Proposed. En3-5/6-2009E. Ottawa: Fisheries and Oceans Canada. 2009. Accessed December 04, 2013 at

Illinois State Museum. 2006. "Mussel glossary" (On-line). Accessed October 01, 2013 at

American Museum of Natural History, 2013. "Lampsilis cariosa species summary" (On-line). Genus Lampsilis. Accessed December 08, 2013 at

Arey, L. 1932. The formation and structure of the glochidial cyst. Biological Bulletin, 62.2: 212-221.

Bogan, A. 1996. "Lampsilis cariosa" (On-line). Accessed October 01, 2013 at

Bruenderman, S., J. Sternburg, C. Barnhart. 2002. "Missouri’s Freshwater Mussels" (On-line pdf). Accessed December 04, 2013 at

Jirka, K., D. Strayer. 1997. "The Pearly Mussels of New York State" (On-line pdf). Accessed December 04, 2013 at

Kelly, M., J. Rhymer. 2005. Population genetic structure of a rare unionid (Lampsilis cariosa) in a recently glaciated landscape. Conservation Genetics, 6: 789-802.

Kurth, J. 2007. Methods for the Translocation of the Yellow Lampmussel (Lampsilis cariosa) and the Tidewater Mucket (Leptodea ochracea) in the Fort Halifax Dam Impoundment of the Sebasticok River, Maine. Orono: University of Maine. Accessed December 04, 2013 at

Mock, J., J. Brim-Box, M. Miller, M. Downing, W. Hoeh. 2004. Genetic diversity and divergence among freshwater mussel (Anodonta) populations in the Bonneville Basin of Utah. Molecular Ecology, 13: 1085-1098.

Sabine, D., S. Makepeace, D. McAlpine. 2004. The yellow lamp mussel (Lampsilis cariosa) in New Brunswick: a population of significant conservation value. Northeastern Naturalist, 11/4: 407-420.

Strayer, D. 1993. Macrohabitats of freshwater mussels (Bivalvia:Unionacea) in streams of the Northern Atlantic Slope. Journal of the North American Benthological Society, 12.3: 236-246.

The University of Georgia Museum of Natural History, 2008. "Yellow lampmussel: Lampsilis cariosa" (On-line). Accessed October 01, 2013 at

Williams, J., A. Bogan, J. Garner, E. Wilson. 2008. Freshwater Mussels of Alabama and the Mobile Basin in Georgia, Mississippi, and Tennessee. Alabama: University of Alabama Press.

Williams, J., M. Warren, Jr., K. Cummings, J. Harris, R. Neves. 1993. Conservation status of freshwater mussels of the United States and Canada. Fisheries, 18.9: 6-22.