The kidneyshell is found in the Ohio, Tennessee and Cumberland river systems. Its range stretches as far north as tributaries of Lake Erie south to Arkansas, Oklahoma, and west to Kansas.
The kidneyshell is usually found in small to medium rivers, usually in areas with fairly good flow. In general substrates it inhabits include sand and/or gravel. (Cummings and Mayer, 1992; van der Schalie, 1938; Watters, 1995)
The kidneyshell is up to 15.2 cm (6 inches) long , elongate, and kidney-shaped. The shell is usually fairly thick, solid and compressed. The anterior end is rounded, the posterior end bluntly pointed. The dorsal margin is straight to slightly curved and the ventral margin is curved, straight or arched.
Umbos are low and even with the hinge line. The beak sculpture is fine, with two to three concentric ridges, and tuberculate toward the posterior.
The periostracum (outer shell layer) is smooth, yellow to yellow-brown with broad green interrupted rays. Older specimens tend to be more brown.
On the inner shell, the left valve has two pseudocardinal teeth, which are thick, heavy, triangular, and serrated. The two lateral teeth are straight to slightly curved, heavy, and short. The right valve has one heavy, compressed, pyramidal pseudocardinal tooth. A smaller roughened tooth may be on either side. The one lateral tooth is wide, heavy, elevated and serrated.
The beak cavity is shallow or absent. Females have undulations or fold on the inside of the shell. The nacre is white and is iridescent posteriorly.
In Michigan, this species can be confused with the mucket, ellipse and rainbow. The kidneyshell generally has a heavier hinge and teeth than these species. The mucket is less elongate and more oval. The ellipse is generally smaller and has wavy green rays on the posterior half of the shell. The rainbow is also generally smaller and has a “v” shaped beak sculpture. (Cummings and Mayer, 1992; Watters, 1995)
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.
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.
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. (Oesch, 1984)
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. The kidneyshell has glochidial packets which resemble larval fish or Simulidae larvae. Fish are likely attracted to these, thinking they are food. How and if the kidneyshell is able to recognize a suitable fish host is unknown.
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.
The parasitic glochidial stage absorbs blood and nutrients from hosts after attachment. Mantle cells within the glochidia feed off of the host’s tissue through phagocytocis. (Arey, 1921; 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)
Fish hosts are determined by looking at both lab metamorphosis 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.
Although fish hosts for P. fasciolaris have not been tested, congeners metamorphose on both Etheostoma and Percina species. In a southeastern Michigan study, Ptychobranchus fasciolaris was significantly associated with the presence of Etheostoma caeruleum, E. blennioides and P. caprodes. These species may be potential hosts. (Barnhart and Roberts, 1997; Haag and Warren, 1997; Mulcrone, 2004)
Mussels are ecological indicators. Their presence in a water body usually indicates good water quality.
There are no significant negative impacts of mussels on humans.
Ptychobranchus fasciolaris is Endangered in Illinois and Special Concern in Indiana. Under the Canadian federal Species At Risk Act, P. fasciolaris is listed as Endangered. (Environment Canada, 2003; Hove, 2004)
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.
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.
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.
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
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.
Barnhart, C., F. Riusech, M. Baird. 1998. Hosts of salamander mussel (Simpsonaias ambigua) and snuffbox (Epioblasma triquetra) from the Meramec River system, Missouri.. Triannual Unionid Report, 16: 34.
Barnhart, M., A. Roberts. 1997. Reproduction and fish hosts of unionids from the Ozark Uplifts. Pp. 16-20 in K Cummings, A Buchanan, C Mayer, T Naimo, eds. Conservation and Management of Freshwater Mussels II. Conservation and Management of Freshwater Mussels II. Proceedings of a UMRCC Symposium, 16-18 October 1995, St. Louis, MissouriProceedings of a UMRCC Symposium, 16-18 October 1995, St. Louis, Missouri.. Rock Island, Illinois: Upper Mississippi River Conservation Committee.
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.
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 http://www.inhs.uiuc.edu/cbd/collections/mollusk/fieldguide.html.
Environment Canada, 2003. "Species At Risk" (On-line). Accessed September 21, 2005 at http://www.speciesatrisk.gc.ca/default_e.cfm.
Haag, W., M. Warren. 1997. Host fishes and reproductive biology of six freshwater mussel species from the Mobile Basin, USA. Journal of the North American Benthological Society, 16: 576-585.
Hove, M. 2004. "Links to each state's listed freshwater mussels, invertebrates, or fauna" (On-line). Accessed September 21, 2005 at http://www.fw.umn.edu/Personnel/staff/Hove/State.TE.mussels.
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.
Mulcrone, R. 2004. Incorporating habitat characteristics and fish hosts to predict freshwater mussel (Bivalvia:Unionidae) distributions in the Lake Erie drainage, southeastern Michigan. Ph.D. Dissertation, Ann Arbor, Michigan: University of Michigan.
Oesch, R. 1984. Missouri naiades, a guide to the mussels of Missouri. Jefferson City, Missouri: Missouri Department of Conservation.
Watters, G. 1995. A guide to the freshwater mussels of Ohio. Columbus, Ohio: Ohio Department of Natural Resources.
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.