The fat mucket is found from the Mississippi River drainage from New York to Minnesota. It occurs south to Arkansas but does not occur from the Tennessee and Cumberland River systems. In the St. Lawrence River system it is found in the Canadian Interior Basin. Lampsilis siliquoidea is also found in Montana and eastern Colorado.
In Michigan L. siliquoidea is found in drainages throughout the state, both in the upper and lower peninsulas.
Biogeographic Regions: nearctic (Native )
occurs (regularly, as a native taxon) in multiple nations
Regularity: Regularly occurring
Type of Residency: Year-round
Regularity: Regularly occurring
Type of Residency: Year-round
Global Range: (>2,500,000 square km (greater than 1,000,000 square miles)) This species occurs throughout the Mississippi River basin except for the Tennessee and Cumberland River basins. The range extends from western New York to Minnesota to Montana (Gangloff and Gustafson, 2000) and south to Arkansas and western into eastern Kansas and Nebraska (Hoke, 2005). It is found as far west as the eastern Colorado border and in Montana and is widespread throughout the interior of Canada, including the western Hudson Bay drainage (Parmalee and Bogan, 1998).
The fat mucket is up to 12.7 cm (5 inches) long , and is oblong to elliptical in shape. The 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. The anterior end is rounded, the posterior end bluntly pointed in males or truncated in females. The dorsal margin is straight and the ventral margin is straight and may be rounded.
Umbos are broad and raised only slightly above the hinge line. The beak sculpture is fine, with six to ten double-loops.
The periostracum (outer shell layer) is yellow to yellow-brown with green rays. Older specimens tend to be darker and brownish.
On the inner shell, the left valve has two pseudocardinal teeth, which are erect and compressed. The two lateral teeth are thin, short and slightly curved. The right valve has one large, erect pseudocardinal tooth. Anterior to this tooth is a smaller (lamellar) tooth. The one lateral tooth is thin and straight.
The beak cavity is shallow to moderately deep. Although the nacre is white, occasionally it is has a pink or salmon tint and iridescent posteriorly.
In Michigan, this species can be confused with the mucket and pocketbook. The mucket is generally more compressed and slightly more elliptically shaped. The pocketbook is more roundly shaped and has higher umbos.
Range length: 12.7 (high) cm.
Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry
Sexual Dimorphism: sexes shaped differently
Jass and Glenn (2004) found the species to be sexually dimorphic with males generally larger than females but females having posterior end inflation and more evenly rounded posterior margin (Jass and Glenn, 2004).
Although found in various substrates and in various habitats from lakes, and headwaters to medium sized rivers, the fat mucket is usually found in quiet water on sandy-mud bottoms. Occasionally it is found in riffles, but usually in waters below riffles, or slowly running water with fine gravel, sand and mud.
Habitat Regions: freshwater
Aquatic Biomes: rivers and streams
Habitat and Ecology
Habitat Type: Freshwater
Comments: This species is found on a variety of substrates but usually prefers quiet or slow-moving water with a mud bottom, typically avoiding riffles (Parmalee and Bogan, 1998).
Non-Migrant: No. All populations of this species make significant seasonal migrations.
Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).
Locally Migrant: No. No populations of this species make annual migrations of over 200 km.
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.
Plant Foods: algae; phytoplankton
Other Foods: detritus ; microbes
Foraging Behavior: filter-feeding
Primary Diet: planktivore ; detritivore
Fish hosts are determined by looking at both lab transformations 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.
The main hosts of Lampsilis siliquoidea are in the family Centrarchidae. Natural infections and glochidial metamorphosis have been observed on bluegill, black crappie, largemouth bass, walleye, white crappie and the yellow perch. Glochidial metamorphosis has also been observed on the longear sunfish, bluntnose minnow, sand shiner, sauger and smallmouth bass.
Ecosystem Impact: parasite
Species Used as Host:
- bluegill, Lepomis macrochirus
- black crappie, Pomoxis nigromaculatus
- largemouth bass, Micropterus salmoides
- walleye, Sander vitreus
- white crappie, Pomoxis annularis
- yellow perch, Perca flavescens
- longear sunfish, Lepomis megalotis
- bluntnose minnow, Pimephales notatus
- sand shiner, Notropis stramineus
- sauger, Sander canadensis
- smallmouth bass, Micropterus dolomieu
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.
- muskrat, Ondatra zibethicus
- mink, Neovison vison
- raccoon Procyon lotor
- otter, Lontra canadensis
- turtles, Testudines
- hellbenders, Cryptobranchus
- freshwater drum, Aplodinotus grunniens
- sheepshead, Archosargus probatocephalus
- lake sturgeon, Acipenser fulvescens
- shortnosed sturgeon, Acipenser brevirostrum
- spotted suckers, Minytrema melanops
- common red-horse, Moxostoma
- catfish, Siluriformes
- pumpkinseed, Lepomis gibbosus
Number of Occurrences
Note: For many non-migratory species, occurrences are roughly equivalent to populations.
Estimated Number of Occurrences: > 300
Comments: It is in every drainage (extirpated from Minnesota River) in most Minnesota Cos. (Sietman, 2003); incl. Red, Lake Superior, Lake of the Woods (Graf, 1997; Cvancara, 1970). In Illinois, it is in small/medium streams throughout (Cummings and Mayer, 1997; Schanzle and Cummings, 1991; Schanzle et al. 2004; Tiemann et al., 2005). Indiana: Blue (Sietman et al., 1995), Tippecanoe (Cummings and Berlocher, 1990), E Fork White (Harmon, 1992), Muscatatuck (Harmon, 1989), St. Joseph, Maumee and Eel (Pryor, 2005). In Ohio, it is throughout (Watters, 1992; 1995; Lyons et al., 2007; Grabarciewicz, 2008; Hoggarth et al., 2007; Watters et al., 2009). In West Virginia, it is in the Upper Ohio/Kanawha (Zeto et al., 1987) and Mud Rivers (Guyandotte drainage) (Schmidt and Zeto, 1986). In South Dakota it is in the Minnesota, upper/mid Big Sioux, James, Vermillion Rivers, and Lake Kampeska (Skadsen and Perkins, 2000; Backlund, 2000; Perkins and Backlund, 2003). In Montana, it is in most tribs. of the Missouri, Marais, Milk, Yellowstone, Little Missouri Rivers; less common in Tongue and Bighorn Rivers (Yellowstone basin), Battle and Beaver Creeks (Milk basin) (Gangloff and Gustafson, 2000; Stagliano, 2010). It is in Arkansas in the Poteau (Vaughn and Spooner, 2004), Cache (Christian et al., 2005), and mouth of White (Gordon, 1982). It is widespread and abundant in Wisconsin (Mathiak, 1979). In Mississippi, it is in the Mississippi River S, Big Black, and Yazoo drainages (Jones et al., 2005). It is rare in Louisiana, from Bayou Bartholomew, Tensas River (questionably) and nearby in W Mississippi (Vidrine, 1993). In Tennessee, it is only in Reelfoot Lake (nearly extirpated) and 1 Wolf trib. (Kesler and Manning, 1996) of the Mississippi (Parmalee and Bogan, 1998). It is statewide in Kentucky (Cicerello and Schuster, 2003); rarely in the Middle Green (Cochran and Layzer, 1993; Gordon, 1991), also S Fork Kentucky (Evans, 2008). It is widespread in Oklahoma in the Kiamichi, Blue, Clear Boggy and Little (Vaughn and Taylor, 1999; Vaughn, 2000) and Bird, Fourteenmile, Pryor and Big Cabin Creeks; Flint Creek; Haw Creek (LeFlore Co.); Glover Rivers and Pennington and Gates Creeks, Spring (Branson, 1966); Neosho, Mountain Fork (Spooner and Vaughn, 2007) and Blue Rivers and Honey and Sparrow Creek (Murray Co.); Poteau River; and Bird, Hominy and Salt Creeks (Branson, 1984). Kansas: Neosho, Marais des Cygnes, and Spring (Branson, 1966) basins, and (declined in Verdigris basin) still upper Fall and Caney Rivers but extirpated from Wakarusa (Tiemann, 2006), Republican, Solomon, Saline, Smoky Hill, Ninnescah, Walnut, and Cottonwood Rivers (Couch, 1997). Recently only dead shells in the Marais des Cygnes, Elk, and Fall Rivers, Kansas (Combes and Edds, 2005). In the Little Blue basin it is in the Kansas and Nebraska portions (Hoke, 2004). In the Big Blue system (SE Nebraska, NE Kansas) it was common as weathered valves and alive in W Fork Big Blue and a hole in the Big Blue mainstem, Nebraska (no recruitment) (Hoke, 2005). It is also known from the Clinton River drainage in Michigan (Trdan and Hoeh, 1993) and upper peninsula (Goodrich and Van der Schalie, 1939). It occurs in the Kalamazoo River (Mulcrone and Mehlne, 2001) and Lakes Michigan, Huron, and St. Clair drainages (Badra and Goforth, 2003), Michigan (Strayer, 1980; Trdan and Hoeh, 1993). Beetle (1989) lists Wyoming occurrences in Converse, Fremont, Natrona, and Platte Cos.; while Cvancara (2005) lists the Bighorn (Big Horn, Freemont Cos.), Tongue (Sheridan Co.), North Platte drainages (Natrona, Converse, Platte Cos.). In Canada it is widespread and abundant in Manitoba (Assiniboine- Watson, 2000; Pip, 2006), Ontario (Metcalfe-Smith et al., 2003), Quebec, Saskatchewan, and less abundant, but widespread in Northwest Territories, and Alberta (most SE of the Cordillera); and undetermined in Nunavut (Metcalfe-Smith and Cudmore-Vokey, 2004); recently Petitot River in British Columbia (BC CDC, pers. comm., 2010).
Comments: Smith and Crabtree (2010) found this species at 9 of 32 sites (1 with recruitment) along the entire length of Pennsylvania's French Creek.
Life History and Behavior
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. While the fat mucket has a fish lure to attract its host fish, if or how it recognizes a specific host is unknown.
Glochidia respond to touch, light and some chemical cues. In general, when touched or a fluid is introduced, they will respond by clamping shut.
Communication Channels: chemical
Perception Channels: visual ; tactile ; vibrations ; chemical
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.
Development - Life Cycle: metamorphosis
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.
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.
Lampsilis siliquoidea is a long-term brooder, and was gravid from early August to late July in the Huron River, Michigan. It probably breeds in July and early August in Michigan.
Breeding interval: The fat mucket breeds once in the warmer months of the year.
Breeding season: In Michigan, the breeding season is probably June to July.
Average gestation period: 10 months.
Key Reproductive Features: seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (Internal ); 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)
Recorded host fishes include several sunfish and perch species (Watters, 1996). Draxler et al. (2006) confirmed glochidial transformation on several fish species including Lepomis macrochirus (bluegill), Perca flavescens (yellow perch), and Micropterus salmoides (largemouth bass).
Molecular Biology and Genetics
Barcode data: Lampsilis siliquoidea
Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.
See the BOLD taxonomy browser for more complete information about this specimen and other sequences.
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Download FASTA File
Statistics of barcoding coverage: Lampsilis siliquoidea
Public Records: 3
Specimens with Barcodes: 9
Species With Barcodes: 1
Lampsilis siliquoidea is currently not listed for conservation status. However, it is commonly found in lakes, where zebra mussels have been thriving.
US Federal List: no special status
CITES: no special status
IUCN Red List Assessment
Red List Category
Red List Criteria
National NatureServe Conservation Status
Rounded National Status Rank: N5 - Secure
Rounded National Status Rank: N5 - Secure
NatureServe Conservation Status
Rounded Global Status Rank: G5 - Secure
Reasons: This species is extremely wide ranging and is stable and secure throughout its range.
Intrinsic Vulnerability: Not intrinsically vulnerable
Environmental Specificity: Broad. Generalist or community with all key requirements common.
Global Short Term Trend: Relatively stable (=10% change)
Global Long Term Trend: Increase of 10-25% to decline of 30%
Global Protection: Unknown whether any occurrences are appropriately protected and managed
Comments: This species occurs in Muddy Creek (French Creek drainage) in the Erie NWR in Crawford Co., Pennsylvania (Mohler et al., 2006). Specimens from the Black River (St. Clair drainage), Michigan, were relocated to the Detroit River in 1992 (Trdan and Hoeh, 1993).
Relevance to Humans and Ecosystems
There are no significant negative impacts of mussels on humans.
Mussels are ecological indicators. Their presence in a water body usually indicates good water quality.
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L. siliquoidea is recognized by its brown shell with dark rays, and is usually about 70 to 100 mm in size. The shape of the shell is oblong to elliptical, compressed or inflated, with uniform thickness. Fatmucket Clams are filter feeders. They feed on algae, phytoplankton, protozoans and organic particles. In the parasitic glochidial stage they feed on blood from hosts species, which include bass, perch, walleye, and sturgeon.
Distribution and habitat
It is widespread in North America, found in the drainages of both the Mississippi River from New York to Minnesota, the Great Lakes, and Hudson Bay. It lives in lakes, rivers, streams and quiet waters, usually on sandy-mud bottoms.
- Turgeon, D. D., A. E. Bogan, E. V. Coan, W. K. Emerson, W. G. Lyons, W. Pratt, et al. (1988) Common and scientific names of aquatic invertebrates from the United States and Canada: mollusks, American Fisheries Society Special Publication 16
- Turgeon, D. D., J. F. Quinn, Jr., A. E. Bogan, E. V. Coan, F. G. Hochberg, W. G. Lyons, et al. (1998) Common and scientific names of aquatic invertebrates from the United States and Canada: Mollusks, 2nd ed., American Fisheries Society Special Publication 26
Names and Taxonomy
Comments: The combination Lampsilis radiata luteola has been used incorrectly in place of Lampsilis siliquoidea and resulted in some confusion. For example, Lampsilis radiata luteola cited in Oesch (1984; 1995) is actually Lampsilis siliquoidea but the two names are not considered synonyms nor is siliquoidea considered a form or subspecies of radiata. Unio (= Lampsilis) luteola, previously confined to the Susquehanna and Mohawk Rivers (Johnson, 1969), falls within the overall range of and is considered a junior synonym of Lampsilis radiata and not as a senior synonym of Lampsilis siliquoidea (see Turgeon et al., 1998). Note Watters et al. (2009) conclude that Unio siliquoidea Barnes, 1823, is a junior synonym of Unio luteola Lamarck, 1819, that intergraded with Lampsilis radiata radiata in northern New York in the Finger Lakes, Erie Canal, Mohawk, and upper Susquehanna Rivers; and therefore synonymize Lampsilis siliquoidea with Lampsilis radiata as a subspecies- Lampsilis radiata luteola.
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