Animal Diversity Web

Ge­o­graphic Range

The mon­key­face mus­sel, Quadrula metanevra, has a Nearc­tic dis­tri­b­u­tion that en­com­passes the Mis­sis­sippi River, Ohio River, and Ten­nessee River basins in the United States. Within Min­nesota, this mus­sel used to re­side in the Min­nesota, the Mis­sis­sippi and St. Croix Rivers. Mon­key­face mus­sles are still found in the Mis­sis­sippi river, but they are very rare within Min­nesota wa­ters. They are be­lieved to have been ex­tir­pated from the Min­nesota River. (Cordeiro, 2010; Min­nesota Dept. of Nat­ural Re­sources, 2011; Na­tional Park Ser­vice, 2006)

• Biogeographic Regions
• nearctic
  • native

Habi­tat

Mon­key­face mus­sels may be found in medium to large rivers and streams. The mon­key­face lives mostly in areas with mixed sand and gravel or gravel areas. (Min­nesota Dept. of Nat­ural Re­sources, 2011; Na­tional Park Ser­vice, 2006)

• Habitat Regions
• temperate
• freshwater

• Aquatic Biomes
• rivers and streams

• Average depth

  2 m

  6.56 ft

Phys­i­cal De­scrip­tion

The outer shell color of mon­key­faces can be a green or light to dark brown. The shells will usu­ally have zig-zags with a green line. Mon­key­face mus­sels can have v-shaped mark­ings as well, but these are more likely to be on the younger mus­sels. The shell is thick, round or square-like. The shells also have a pos­te­rior edge that has large knobs. The inner shell is white on one end while the other end has iri­des­cent col­or­ings. Mon­key­face get their name from the pro­file of the pos­te­rior edge of the shell, where the out­line looks like the silou­ette of a mon­key's face. (Cordeiro, 2010; How­ells, 2010; Min­nesota Dept. of Nat­ural Re­sources, 2011; Na­tional Park Ser­vice, 2006)

• Other Physical Features
• ectothermic
• heterothermic
• bilateral symmetry

• 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

De­vel­op­ment

Fer­til­ized mon­key­face eggs are kept in the fe­male’s gills and de­velop into glochidia (lar­vae). The fe­males may con­tain glochidia in the gills from May to July in Min­nesota. They are re­leased and must at­tach to host fish at the gills or fins. The glochidia live as a par­a­site until they de­velop into ju­ve­niles. After trans­for­ma­tion, the ju­ve­niles de­tach and be­come free liv­ing at the bot­tom of the stream or river. (Min­nesota Dept. of Nat­ural Re­sources, 2011)

• Development - Life Cycle
• metamorphosis

Re­pro­duc­tion

Mon­key­faces spawn once a year in the spring. Males re­lease ga­metes into the water that are taken up by the fe­males. (Min­nesota Dept. of Nat­ural Re­sources, 2011)

• Mating System
• polygynandrous (promiscuous)

Mon­key­faces are short-term brood­ers, mean­ing the fe­males brood the lar­vae (glochidia) in their gills for only a few months in the sum­mer. Re­pro­duc­tion starts with males re­leas­ing sperm di­rectly into the water. The fe­males down­stream siphon the sperm into their gill cham­ber where the eggs are fer­til­ized. The eggs ma­ture in the gills to be­come glochidia. After being brooded for a few weeks or months, the glochidia are dis­charged into the water and will at­tach to a host fish. Brood­ing fe­males were found in Ten­nessee be­tween March and July. Glochidia drop from the host after they trans­form into ju­ve­niles. (Gar­ner, et al., 1999; Min­nesota Dept. of Nat­ural Re­sources, 2011; Na­tional Park Ser­vice, 2006)

• Key Reproductive Features
• seasonal breeding
• fertilization
  • internal
• ovoviviparous

• Breeding interval

  Monkeyface mussels breed once yearly.

• Breeding season

  Monkeyface mussels breed from May to July in Minnesota.

After the eggs are fer­til­ized, the lar­vae, called glochidia, re­side in the fe­male's gills 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

Lifes­pan/Longevity

The spe­cific lifes­pan of the mon­key­face is un­known. How­ever, unionid mus­sels can be long-lived, with some mus­sel species liv­ing from decades to a cen­tury or more. (Min­nesota Dept. of Nat­ural Re­sources, 2011; US Army Corps of En­gi­neers, 2005)

Be­hav­ior

Mon­key­face mus­sels are mostly seden­tary, but can move in the sed­i­ment. The mus­sels can move via a hatchet shaped mus­cle that is ex­tended be­tween its two shells. (Min­nesota Dept. of Nat­ural Re­sources, 2011)

• Key Behaviors
• parasite
• sessile
• sedentary

Home Range

The home range for mon­key­faces is un­known. Adult mus­sels move only a few me­ters from where they set­tle as ju­ve­niles.

Com­mu­ni­ca­tion and Per­cep­tion

Mus­sels in gen­eral are likely able to re­spond to chem­i­cal cues for spawn­ing and other be­hav­iors.

• Perception Channels
• tactile
• chemical

Food Habits

Mon­key­face mus­sels are pri­mar­ily fil­ter feed­ers on algae, bac­te­ria, pro­to­zoans and other or­ganic mat­ter pre­sent in the water. Mon­key­faces draw water in through their in­cur­rent siphon and the food and oxy­gen are re­moved from their gills. The fil­tered water and waste are re­leased from an ex­cur­rent siphon. (Min­nesota Dept. of Nat­ural Re­sources, 2011)

• Primary Diet
• herbivore
  • algivore

• Other Foods
• detritus
• microbes

• Foraging Behavior
• filter-feeding

Pre­da­tion

Unionid mus­sels in gen­eral are preyed upon by rac­coons (Pro­cyon lotor), muskrats (On­do­tra zi­bethi­cus), and river ot­ters (Lon­tra canaden­sis). Their hard shells and the mus­cles that hold them closed pro­tect them from preda­tors. (U. S. Fish and Wildlife Ser­vice, 2011)

• Anti-predator Adaptations
• cryptic

• Known Predators

  • raccoons (Procyon lotor)
  • muskrats (Ondotra zibethicus)
  • river otters (Lontra canadensis)

Ecosys­tem Roles

Unionid mus­sels fil­ter the water, pro­vide sub­strate for aquatic in­sects and are a part of nu­tri­ent cy­cling in streams. Some of the known host fish for the glochidia of this species are the sun­fish (Lep­omis), sauger (Sti­zoste­dion canadens) and the bluegill (Lep­omis macro­hirus). (Min­nesota Dept. of Nat­ural Re­sources, 2011; Na­tional Park Ser­vice, 2006)

• Ecosystem Impact
• creates habitat
• parasite

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Mus­sels in gen­eral are good in­di­ca­tors of water qual­ity. This is be­cause they do not move around much, can be long liv­ing and can be an­a­lyzed for con­t­a­m­i­nants that are in the water where they live. As the qual­ity of the water de­clines so may the pop­u­la­tion of the mus­sels. Mus­sels have also been im­por­tant in the cul­tured pearl in­dus­try. Thicker shelled species are har­vested to seed pearl oys­ters. (Na­tional Park Ser­vice, 2006)

• Positive Impacts
• body parts are source of valuable material

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

No neg­a­tive eco­nomic im­pacts are known for mon­key­face mus­sels.

Con­ser­va­tion Sta­tus

Quadrula metanevra is listed on sev­eral state threat­ened and en­dan­gered lists. Mon­key­face mus­sles are en­dan­gered in Ohio, threat­ened in Wis­con­sin and Min­nesota, and spe­cial con­cern in Arkansas. Due to de­creas­ing water qual­ity through­out its range this species may be be­com­ing more rare. (Cordeiro, 2010; Hove, 2008; Min­nesota Dept. of Nat­ural Re­sources, 2011)

• IUCN Red List

  Not Evaluated

• US Federal List

  No special status

• CITES

  No special status

• State of Michigan List

  No special status

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.

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.