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Quadrula metanevra

What do they look like?

Monkeyfaces are mussles with thick, round, or squarish shells. They get their name because the back edge of the shell looks like the face of a monkey. Their shells are green, light brown, or dark brown on the outside with green zig-zags. Younger monkeyfaces often have v-shaped markings, too. The shells also have bumps along the back edge. Inside, the shell is white on one side and iridescent on the other. (Cordeiro, 2010; Howells, 2010; Minnesota Dept. of Natural Resources, 2011; National Park Service, 2006)

  • Sexual Dimorphism
  • sexes alike
  • Range length
    5.1 to 12.7 cm
    2.01 to 5.00 in
  • Average length
    8.9 cm
    3.50 in

Where do they live?

Monkeyface mussels live in the United States. They live in the Mississippi River, the Ohio River, the Tennessee River, and the rivers that drain into them. They used to be found in the Minnesota River, but are not found there anymore. (Cordeiro, 2010; Minnesota Dept. of Natural Resources, 2011; National Park Service, 2006)

What kind of habitat do they need?

Monkeyface mussels live in medium and large rivers and streams. They mostly live mostly in places with sand and gravel or all gravel bottoms. (Minnesota Dept. of Natural Resources, 2011; National Park Service, 2006)

  • Aquatic Biomes
  • rivers and streams
  • Average depth
    2 m
    6.56 ft

How do they grow?

Monkeyface eggs develop into larvae called glochidia inside the gills of their mother. Females might have larvae in their gills from May to July. The females release the larvae, and they attach to the gills or fins of fish. They stick themselves on the fish and keep growing until they become juveniles. Later, they let go of the fish and settle on the bottom of the stream or river, where they grow into adults. (Minnesota Dept. of Natural Resources, 2011)

How do they reproduce?

Monkeyfaces reproduce once a year in the spring. Males release reproductive cells into the water. Females take up these cells to fertilize their eggs. (Minnesota Dept. of Natural Resources, 2011)

Males release their reproductive cells into the water, and females downstream take them up to fertilize the eggs. The eggs hatch into larvae inside the gills of their mothers. They stay there for just a few months in the summertime. After a few weeks or months, they are released into the water and attach to a host fish. The larvae grow and develop attached to the host, and then let go and settle on the bottom. (Garner, et al., 1999; Minnesota Dept. of Natural Resources, 2011; National Park Service, 2006)

  • How often does reproduction occur?
    Monkeyface mussels breed once yearly.
  • Breeding season
    Monkeyface mussels breed from May to July in Minnesota.

Monkeyface larvae grow in the gills of their mother for a few months until they are released into the water. (Minnesota Dept. of Natural Resources, 2011)

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

How long do they live?

Scientists don't know the lifespan of monkeyfaces in particular. Freshwater mussels can live 20 to even 100 years or more. (Minnesota Dept. of Natural Resources, 2011; US Army Corps of Engineers, 2005)

How do they behave?

Monkeyface mussels mostly stay in the same place, but are able to move around on the bottom. They move using a muscle that they stick out from between their two shells. (Minnesota Dept. of Natural Resources, 2011)

Home Range

Scientists don't know the size of the area where monkeyfaces live. Most mussels don't move very much after they grow into adults.

How do they communicate with each other?

Mussels can probably respond to chemical signals that cause them to reproduce or other behaviors.

What do they eat?

All mussels are filter feeders, meaning that they strain bits of food out of the water. They pull water through pores and into their gills using cilia, which look like tiny hairs. The bits of food get trapped in their gills and then mucous moves the food to their digestive system. This way, they eat on algae, bacteria, protozoans and other bits of plants or animals found in the water. (Minnesota Dept. of Natural Resources, 2011)

What eats them and how do they avoid being eaten?

Freshwater mussels are eaten by raccoons, muskrats, and river otters. Their hard shells and the muscles that hold them closed protect them from predators. (U. S. Fish and Wildlife Service, 2011)

  • These animal colors help protect them
  • cryptic

What roles do they have in the ecosystem?

Freshwater mussels filter and clean the water where they live, and cycle nutrients through streams. They provide a surface for insects living in the water. Some of the fish their larvae attach to are sunfish, saugers, and bluegills. (Minnesota Dept. of Natural Resources, 2011; National Park Service, 2006)

  • Ecosystem Impact
  • creates habitat
  • parasite
Species (or larger taxonomic groups) used as hosts by this species
  • sunfish (Lepomis)
  • saugers (Stizostedion canadens)
  • bluegills (Lepomis macrohirus)

Do they cause problems?

No negative economic impacts are known for monkeyface mussels.

How do they interact with us?

Mussels are used by researchers to test water quality. They don't move around much and live for a long time, so scientists can check their bodies for contaminants. When the water quality declines, the number of mussels might also decline. Mussels are also used for pearl oysters. (National Park Service, 2006)

  • Ways that people benefit from these animals:
  • body parts are source of valuable material

Are they endangered?

Monkeyface mussels are endangered in Ohio, threatened in Wisconsin and Minnesota, and under special concern in Arkansas. Their numbers might be decreasing because the water quality is getting worse. (Cordeiro, 2010; Hove, 2008; Minnesota Dept. of Natural Resources, 2011)

Contributors

Jordy Veit (author), Minnesota State University, Mankato, Robert Sorensen (editor), Minnesota State University, Mankato, Renee Mulcrone (editor), Special Projects, Catherine Kent (editor), Special Projects.

Glossary

Nearctic

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.

chemical

uses smells or other chemicals to communicate

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

detritus

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

ectothermic

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

fertilization

union of egg and spermatozoan

filter-feeding

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.

freshwater

mainly lives in water that is not salty.

herbivore

An animal that eats mainly plants or parts of plants.

heterothermic

animals that have little or no ability to regulate their body temperature, body temperatures fluctuate with the temperature of their environment, often referred to as 'cold-blooded'.

internal fertilization

fertilization takes place within the female's body

metamorphosis

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.

native range

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

ovoviviparous

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

polygynandrous

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

sedentary

remains in the same area

sessile

non-motile; permanently attached at the base.

tactile

uses touch to communicate

temperate

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).

References

Cordeiro, J. 2010. "Quadrula metanevra" (On-line). NatureServe. Accessed July 07, 2011 at http://www.natureserve.org/explorer/servlet/NatureServe?searchName=Quadrula+metanevra+.

Garner, J., T. Haggerty, R. Modlin. 1999. Reproductive cycle of Quadrula metanevra (Bivalvia: Unionidae) in the Pickwick Dam tailwater of the Tennessee River. American Midland Naturalist, 141 (2): 277-283.

Hove, M. 2008. "State's listed freshwater mollusks, invertebrates, or fauna" (On-line). Accessed February 03, 2012 at http://fwcb.cfans.umn.edu/personnel/staff/hove/State.TE.mussels.html.

Howells, R. 2010. "The Ecology of Fresh Water Mussels: Species of Interest" (On-line). Accessed July 07, 2011 at http://www.texasahead.org/economic_developer/endangered_species/mussel_presentations/EcologyOfFreshwaterMusselsOfInterest_Howells.pdf.

Minnesota Dept. of Natural Resources, 2011. "Quadrula metanevra (Rafinesque, 1820)" (On-line). Minnesota Department of Natural Resources Rare Species Guide. Accessed July 21, 2011 at http://www.dnr.state.mn.us/rsg/profile.html?action=elementDetail&selectedElement=IMBIV39080.

National Park Service, 2006. "Monkeyface" (On-line). Mississippi National River and Recreation Area. Accessed July 11, 2011 at http://www.nps.gov/miss/naturescience/musspagemonk.htm.

U. S. Fish and Wildlife Service, 2011. "Discover Freshwater Mussels: America's Hidden Treasure" (On-line). U. S. Fish and Wildlife Service News. Accessed July 11, 2011 at http://www.fws.gov/news/mussels.html.

US Army Corps of Engineers, 2005. "What is a Freshwater Mussel?" (On-line). Accessed July 07, 2011 at http://el.erdc.usace.army.mil/mussels/freshwater.html.

 
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Veit, J. 2013. "Quadrula metanevra" (On-line), Animal Diversity Web. Accessed April 23, 2014 at http://www.biokids.umich.edu/accounts/Quadrula_metanevra/

BioKIDS is sponsored in part by the Interagency Education Research Initiative. It is a partnership of the University of Michigan School of Education, University of Michigan Museum of Zoology, and the Detroit Public Schools. This material is based upon work supported by the National Science Foundation under Grant DRL-0628151.
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