Toxolasma paulum - (I. Lea, 1840)
Iridescent Lilliput
Taxonomic Status: Accepted
Related ITIS Name(s): Toxolasma paulus (I. Lea, 1840) (TSN 80366)
Unique Identifier: ELEMENT_GLOBAL.2.113016
Element Code: IMBIV43060
Informal Taxonomy: Animals, Invertebrates - Mollusks - Freshwater Mussels
 
Kingdom Phylum Class Order Family Genus
Animalia Mollusca Bivalvia Unionoida Unionidae Toxolasma
Genus Size: C - Small genus (6-20 species)
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Concept Reference
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Concept Reference: Turgeon, D.D., J.F. Quinn, Jr., A.E. Bogan, E.V. Coan, F.G. Hochberg, W.G. Lyons, P.M. Mikkelsen, R.J. Neves, C.F.E. Roper, G. Rosenberg, B. Roth, A. Scheltema, F.G. Thompson, M. Vecchione, and J.D. Williams. 1998. Common and scientific names of aquatic invertebrates from the United States and Canada: Mollusks. 2nd Edition. American Fisheries Society Special Publication 26, Bethesda, Maryland: 526 pp.
Concept Reference Code: B98TUR01EHUS
Name Used in Concept Reference: Toxolasma paulus
Taxonomic Comments: Considered Carunculina by van der Schalie (1940), Johnson (1970), Johnson (1972), Burch (1975), and Heard (1979). The previously listed authors have assigned southeastern populations to T. parvus (Barnes, 1823), whose populations are hermaphroditic. It is thought that both sexually dimorphic populations (these will be refered to as T. paulus) and hermaphroditic populations (which should be refered to as T. parvus until further studies determine otherwise, according to Walter Hoe) occur in the Apalachicolan region. Several synonyms for Toxolasma species are known from the Apalachicolan region and peninsular Florida, particularly the Apalachicolan river system, of which T. paulus is the earliest. The form T. minor (Lea, 1838) has not been validated, but may represent peninsular Florida populations. The entire genus needs genetic studies to determine the validity of the various forms. For now, all regional populations are referred to as a single species, T. paulus.. For now, all regional populations are referred to as a single species, T. paulus. The spelling Toxolasma paulus formerly followed Turgeon et al. (1998). When the genus name Toxolasma was proposed by Rafinesque (1831), he did not designate a gender nor was it clear from the species included in the genus. A recent review of Toxolasma (Lee, 2006) determined the gender is neuter and endings of four species have changed: Toxolasma lividus to lividum; Toxolasma parvus to parvum; Toxolasma paulus to paulum; and Toxolasma texasensis to texasense. Through misinterpretations of species identities and synonomy, Toxolasma has been considered to contain two to eight species (e.g., Johnson, 1970; Burch, 1975; Turgeon et al. 1988; Turgeon et al, 1998). Examination of museum vouchers indicate that there may be as many as 15 species. These recent publications have been little more than species lists and present no explanation for the synonomies.
Conservation Status
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NatureServe Status

Global Status: G4G5Q
Global Status Last Reviewed: 21May2009
Global Status Last Changed: 21May2007
Rounded Global Status: G4 - Apparently Secure
Reasons: The range of this species is fairly large for a regional endemic, populations are apparently stable, and somewhat expanding, distribution is relatively wide, and the species exhibits a wide habitat tolerance.
Nation: United States
National Status: N4N5 (21May2007)

U.S. & Canada State/Province Status
Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
United States Alabama (S2), Florida (SNR), Georgia (S5)

Other Statuses

American Fisheries Society Status: Currently Stable (01Jan1993)

NatureServe Global Conservation Status Factors

Range Extent: 1000-5000 square km (about 400-2000 square miles)
Range Extent Comments: The global range is considered here to include the Apalachicolan region in Florida, Alabama, and Georgia, and in much of peninsular Florida (Williams et al., 2008). In these areas, it occurs in all the major drainages and some of the minor drainages as well, inhabiting almost all size streams, spring runs, some lakes, and reservoirs. One of the widest ranging species in these areas. In the Apalachicola Basin (ACF basin = formed by Apalachicola, Chattahoochee, and Flint Rivers) of Alabama, Florida, and Georgia, this species is historically known from 214 records from 91 sites and was considered widespread throughout the ACF system including the main channel and tributaries of the Apalachicola, Chipola, Chattahoochee, and Flint Rivers (Brim Box and Williams, 2000).

Area of Occupancy: 501-12,500 4-km2 grid cells
Area of Occupancy Comments:  

Number of Occurrences: 81 to >300
Number of Occurrences Comments: There are 30 or more peninsular Florida occurrences, and nearly 80 Apalachicolan region occurrences: 15 Alabama, 25 Georgia, 37 Florida. It is very generally distributed in most of the rivers representing these regions (although overlooked in the Escambia river system by Clench and Turner [1956], it is presently known from several occurrences there as well). Most Alabama and Georgia, and many Florida, occurrences are historic. However, new occurrences are not hard to come by. It is one of the most widespread unionids in the two regions considered here, and has the potential for more occurrences considering that it occurs in small streams, large rivers, lakes, and impoundments. In Alabama, it is poorly known and restricted to the Apalachicola basin (Mirarchi, 2004). Specifically, Williams et al. (2008) noted extant Alabama occurrences in Big and Cowarts Creeks, headwater streams of the Chipola River in Houston Co.; and one site in the Chattahoochee River proper and in Halawakee Creek, Lee Co., and Uchee Creek, Russell Co. Most records for the Choctawhatchee, Yellow, and Escambia River drainages are now believed to be Toxolasma sp. (Williams et al., 2008). In the ACF basin, it was recently collected from 59 of 323 sites in Alabama, Florida, and Georgia and is found mainly in tributary streams but also in the main channel of the Chattahoochee River (Brim-Box and Williams, 2000). Golladay et al. (2004) found this species at 13 of 21 sites (1999) and 12 of 21 sites (2001) in tributary streams of the lower Flint River Basin on the Gulf Coastal Plain in southwest Georgia. Specimens of this species were recently found in a survey of ten sites in the Chickasawhatchee Wildlife Management Area and six sites in the Elmodel Wildlife Management Area in Chickasawhatchee Creek and Ichawaynochaway Creek in southwest Georgia (Battle et al., 2003).

Population Size: 2500 - 10,000 individuals
Population Size Comments: At the best known site, approximately 60 specimens per hour of effort could be obtained during a very low water period in June 1988. The species appears to be common to not uncommon at most sites. In 1999 and 2001, this species was found in 13 sites (231 specimens) and 12 sites (427 specimens), respectively, in surveys of 21 sites (each year) in about a dozen tributary streams of the lower Flint River Basin, in southwestern Georgia (Golladay et al., 2004). In the ACF basin, it was recently collected from 59 of 324 sites (360 live, 137 shells) in Alabama, Florida, and Georgia and is found mainly in tributary streams but also in the main channel of the Chattahoochee River (Brim-Box and Williams, 2000).

Number of Occurrences with Good Viability/Integrity: Unknown

Overall Threat Impact Comments: Populations are threatened locally by siltation from poorly conducted agricultural and silvicultural activities, chicken farm litter nutrients (southern Alabama); gravel/sand/phosphate mining, gas/oil exploration (Escambia system); industrial, municipal, residential pollution; watershed development, urban sprawl in middle St. Johns River/greater Tampa Bay/greater Atlanta areas; competition from Asian clam is possible. Following a drought from 1999-2001, this species experienced decline in abundance in the Flint River drainage as evidenced by surveys in 2001 and 2002 (Chastain et al., 2005).

Short-term Trend: Relatively Stable (<=10% change)
Short-term Trend Comments: This species is apparently stable in overall population size. It may be expanding its range to some degree; it is now abundant at the best known site, but was not reported there by Clench and Turner (1956). This may be correlated to the fact that water quality (point source?) in the system has improved (it was once one of the most polluted rivers in the U.S.), or possibly to an increase in the siltiness of substrates in the stream's preferred marginal areas. In the ACF basin, it was recently collected from 59 of 323 sites in Alabama, Florida, and Georgia and is found mainly in tributary streams but also in the main channel of the Chattahoochee River (Brim-Box and Williams, 2000).

Long-term Trend: Decline of <30% to increase of 25%

Intrinsic Vulnerability: Not intrinsically vulnerable

Environmental Specificity: Broad. Generalist or community with all key requirements common.
Environmental Specificity Comments: As Carunculina parva (Barnes, 1823), "lives in shallow water near the edges of streams and ponds, generally in mud, sometimes in sand" (Johnson, 1972). Te species lives "In mud and sand of small streams with slight current and [in] lakes" (Heard, 1979). Generally, it is found in medium-sized streams to medium-sized rivers. In the ACF basin, Brim Box and Williams (2000) found 40% of individuals at sites with primarily sand and rock substrates, 31% at sites with sand and clay substrates, and 23% at sites with primarily sand substrates. It is relatively tolerant of moderate siltation and habitat modifications; typical liabilities of filter-feeders (e.g., to excessive pollutants, eutrophication, etc.).

Other NatureServe Conservation Status Information

Inventory Needs: Determine status of extant populations, resurvey historic EOs, search for new occurrences by conducting intensive surveys in any unsampled water bodies in the Apalachicolan region and peninsular FL.

Protection Needs: Establish buffers and streamside management zones for all agricultural, silvicultural, mining, and developmental activities; maintain good water and benthic habitat quality. Given a relatively low protection needs priority due to its abundance and wide range.

Distribution
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Global Range: (1000-5000 square km (about 400-2000 square miles)) The global range is considered here to include the Apalachicolan region in Florida, Alabama, and Georgia, and in much of peninsular Florida (Williams et al., 2008). In these areas, it occurs in all the major drainages and some of the minor drainages as well, inhabiting almost all size streams, spring runs, some lakes, and reservoirs. One of the widest ranging species in these areas. In the Apalachicola Basin (ACF basin = formed by Apalachicola, Chattahoochee, and Flint Rivers) of Alabama, Florida, and Georgia, this species is historically known from 214 records from 91 sites and was considered widespread throughout the ACF system including the main channel and tributaries of the Apalachicola, Chipola, Chattahoochee, and Flint Rivers (Brim Box and Williams, 2000).

U.S. States and Canadian Provinces

Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
Color legend for Distribution Map
Endemism: endemic to a single nation

U.S. & Canada State/Province Distribution
United States AL, FL, GA

Range Map
No map available.

U.S. Distribution by Watershed (based on multiple information sources) Help
Ecology & Life History
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Basic Description: A small, dark, suboval, relatively thick shelled freshwater mussel.
General Description: See Clench and Turner (1956).
Diagnostic Characteristics: Small size, oval outline, generally sexually dimorphic, relatively thick-shelled and heavy pseudocardinal-toothed, very dark periostracum, females with caruncles-thumb-like modifications of the mantles.
Reproduction Comments: This species is probably bradytictic (long-term brooder). Florida gravidity records have been documented for 2 March 1988 and 26 June 1988. Some populations are sexually dimorphic while others are hermaphroditic (W.R. Hoeh, personal communication), indicating that there are possibly at least two species in the deep southeast. The caruncles may be rotated in order to attract potential host fish. The glochidial host is not known.
Habitat Type: Freshwater
Non-Migrant: N
Locally Migrant: N
Long Distance Migrant: N
Mobility and Migration Comments: An active species for a mussel. It exhibits vertical migrations following water level fluctuations, leaving sometimes long trails in the substrate. Dispersal occurs while the glochidia are encysted on their host (probably a fish).
Riverine Habitat(s): BIG RIVER, CREEK, Low gradient, MEDIUM RIVER, Moderate gradient, Pool
Lacustrine Habitat(s): Shallow water
Special Habitat Factors: Benthic
Habitat Comments: As Carunculina parva (Barnes, 1823), "lives in shallow water near the edges of streams and ponds, generally in mud, sometimes in sand" (Johnson, 1972). Te species lives "In mud and sand of small streams with slight current and [in] lakes" (Heard, 1979). Generally, it is found in medium-sized streams to medium-sized rivers. In the ACF basin, Brim Box and Williams (2000) found 40% of individuals at sites with primarily sand and rock substrates, 31% at sites with sand and clay substrates, and 23% at sites with primarily sand substrates.
Adult Food Habits: Detritivore
Immature Food Habits: Parasitic
Food Comments: Presumably fine particulate organic matter, primarily detritus, and/or zooplankton, and/or phytoplankton (Fuller, 1974). Larvae (glochidia) of freshwater mussels generally are parasitic on fish and there may be a specificity among some species.
Length: 4.1 centimeters
Economic Attributes Not yet assessed
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Management Summary
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Biological Research Needs: Genetic studies to validate the various area forms; determine life history, reproductive biology, fecundity, viability of extant populations, sensitivity to excessive silt and nutrients, and to pollutants; determine host fish, its requirements, and population status; most of these needs should have a relatively low priority due to its abundance and wide range.
Population/Occurrence Delineation
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Group Name: Freshwater Mussels

Use Class: Not applicable
Minimum Criteria for an Occurrence: Occurrences are based on some evidence of historical or current presence of single or multiple specimens, including live specimens or recently dead shells (i.e., soft tissue still attached and/or nacre still glossy and iridescent without signs of external weathering or staining), at a given location with potentially recurring existence. Weathered shells constitute a historic occurrence. Evidence is derived from reliable published observation or collection data; unpublished, though documented (i.e. government or agency reports, web sites, etc.) observation or collection data; or museum specimen information.
Mapping Guidance: Based on the separation distances outlined herein, for freshwater mussels in STANDING WATER (or backwater areas of flowing water such as oxbows and sloughs), all standing water bodies with either (1) greater than 2 km linear distance of unsuitable habitat between (i.e. lotic connections), or (2) more than 10 km of apparently unoccupied though suitable habitat (including lentic shoreline, linear distance across water bodies, and lentic water bodies with proper lotic connections), are considered separate element occurrences. Only the largest standing water bodies (with 20 km linear shoreline or greater) may have greater than one element occurrence within each. Multiple collection or observation locations in one lake, for example, would only constitute multiple occurrences in the largest lakes, and only then if there was some likelihood that unsurveyed areas between collections did not contain the element.

For freshwater mussels in FLOWING WATER conditions, occurrences are separated by a distance of more than 2 stream km of unsuitable habitat, or a distance of more than 10 stream km of apparently unoccupied though suitable habitat. Standing water between occurrences is considered suitable habitat when calculating separation distance for flowing water mussel species unless dispersal barriers (see Separation Barriers) are in place.

Several mussel species in North America occur in both standing and flowing water (see Specs Notes). Calculation of separation distance and determination of separation barriers for these taxa should take into account the environment in which the element was collected. Juvenile mussels do not follow this pattern and juveniles are typically missed by most standard sampling methods (Hastie and Cosgrove, 2002; Neves and Widlak, 1987), therefore juvenile movement is not considered when calculating separation distance.

Separation Barriers: Separation barriers within standing water bodies are based solely on separation distance (see Separation Distance-suitable, below). Separation barriers between standing water bodies and within flowing water systems include lack of lotic connections, natural barriers such as upland habitat, absence of appropriate species specific fish hosts, water depth greater than 10 meters (Cvancara, 1972; Moyle and Bacon, 1969) or anthropogenic barriers to water flow such as dams or other impoundments and high waterfalls.
Separation Distance for Unsuitable Habitat: 2 km
Separation Distance for Suitable Habitat: 10 km
Alternate Separation Procedure: None
Separation Justification: Adult freshwater mussels are largely sedentary spending their entire lives very near to the place where they first successfully settled (Coker et al., 1921; Watters, 1992). Strayer (1999) demonstrated in field trials that mussels in streams occur chiefly in flow refuges, or relatively stable areas that displayed little movement of particles during flood events. Flow refuges conceivably allow relatively immobile mussels to remain in the same general location throughout their entire lives. Movement occurs with the impetus of some stimulus (nearby water disturbance, physical removal from the water such as during collection, exposure conditions during low water, seasonal temperature change or associated diurnal cycles) and during spawning. Movement is confined to either vertical movement burrowing deeper into sediments though rarely completely beneath the surface, or horizontal movement in a distinct path often away from the area of stimulus. Vertical movement is generally seasonal with rapid descent into the sediment in autumn and gradual reappearance at the surface during spring (Amyot and Downing, 1991; 1997). Horizontal movement is generally on the order of a few meters at most and is associated with day length and during times of spawning (Amyot and Downing, 1997). Such locomotion plays little, if any, part in the distribution of freshwater mussels as these limited movements are not dispersal mechanisms. Dispersal patterns are largely speculative but have been attributed to stream size and surface geology (Strayer, 1983; Strayer and Ralley, 1993; van der Schalie, 1938), utilization of flow refuges during flood stages (Strayer, 1999), and patterns of host fish distribution during spawning periods (Haag and Warren, 1998; Watters, 1992). Lee and DeAngelis (1997) modeled the dispersal of freshwater into unoccupied habitats as a traveling wave front with a velocity ranging from 0.87 to 2.47 km/year (depending on mussel life span) with increase in glochidial attachment rate to fish having no effect on wave velocity.

Nearly all mussels require a host or hosts during the parasitic larval portion of their life cycle. Hosts are usually fish, but a few exceptional species utilize amphibians as hosts (Van Snik Gray et al., 2002; Howard, 1915) or may metamorphose without a host (Allen, 1924; Barfield et al., 1998; Lefevre and Curtis, 1911; 1912). Haag and Warren (1998) found that densities of host generalist mussels (using a variety of hosts from many different families) and displaying host specialists (using a small number of hosts usually in the same family but mussel females have behavioral modifications to attract hosts to the gravid female) were independent of the densities of their hosts. Densities of non-displaying host specialist mussels (using a small number of hosts usually in the same family but without host-attracting behavior) were correlated positively with densities of their hosts. Upstream dispersal of host fish for non-displaying host specialist mussels could, theoretically, transport mussel larvae (glochidia) over long distances through unsuitable habitat, but it is unlikely that this occurs very often. D. Strayer (personal communication) suggested a distance of at least 10 km, but a greater distance between occurrences may be necessary to constitute genetic separation of populations. As such, separation distance is based on a set, though arbitrary, distance between two known points of occurrence.

Date: 18Oct2004
Author: Cordeiro, J.
Notes: Contact Jay Cordeiro (jay_cordeiro@natureserve.org) for a complete list of freshwater mussel taxa sorted by flow regime.
Population/Occurrence Viability
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U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed
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Authors/Contributors
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NatureServe Conservation Status Factors Edition Date: 21May2007
NatureServe Conservation Status Factors Author: Cordeiro, J. (2007); BUTLER, R.S. (1992)
Element Ecology & Life History Edition Date: 21May2007
Element Ecology & Life History Author(s): Cordeiro, J. (2007); BUTLER, R.S. (1992)

Zoological data developed by NatureServe and its network of natural heritage programs (see Local Programs) and other contributors and cooperators (see Sources).

References
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  • Battle, J., S.W. Golladay, and A.R. Bambarger. 2003. Mussel conservation in the Chickasawhatchee and Elmodel Wildlife Management Areas: methods for a relocation study. Pages 860-863 in K.J. Hatcher (ed.) Proceedings of the Georgia Water Resources Conference, Institute of Ecology, The University of Georgia, Athens, Georgia.

  • Burch, J.B. 1975c. Freshwater Unionacean Clams (Mollusca: Pelecypoda) of North America: Biota of Freshwater Ecosystems, Identification Manual No 11. Environmental Protection Agency, Washington, D.C. 176 pp.

  • Chastain, C.A., S.W. Golladay, and T.K. Muenz. 2005. Distribution of unionid mussels in tributaries of the lower Flint River, southwestern Georgia: an examination of current and historical trends. Presented at the Proceedings of the 2005 Georgia Water Resources Conference, 25-27 April 2005, University of Georgia.

  • Clench, W.J. and R.D. Turner. 1956. Freshwater mollusks of Alabama, Georgia, and Florida from the Escambia to the Suwanee River. Bulletin of the Florida State Museum Biological Sciences, 1(3): 97-239.

  • Clench, William J., and Ruth D. Turner. 1956. Freshwater mollusks of Alabama, Georgia, and Florida from the Escambia to the Suwanee River. Bulletin of the Florida State Museum Biological Sciences. I(3):180-181.

  • Fuller, S.L.H. 1974. Chapter 8: Clams and mussels (Mollusca: Bivalvia). Pages 215-273 in: C.W. Hart, Jr. and S.L.H. Fuller (eds.) Pollution Ecology of Freshwater Invertebrates. Academic Press: New York. 389 pp.

  • Golladay, S.W., P. Gagnon, M. Kearns, J.M. Battle, and D.W. Hicks. 2004. Response of freshwater mussel assemblages (Bivalvia: Unionidae) to a record drought in the Gulf Coastal Plain of southwestern Georgia. Journal of the North American Benthological Society, 23(3): 494-506.

  • Heard, W.H. 1979. Identification manual of the fresh water clams of Florida. State of Florida, Department of Environmental Regulation, Technical Series, 4(2): 1-82.

  • Howard, A.D. 1915. Some exceptional cases of breeding among the Unionidae. The Nautilus 29:4-11.

  • JOHNSON, R.I. 1970. THE SYSTEMATICS AND ZOOGEOGRAPHY OF THE UNIONIDAE OF THE SOUTHERN ATLANTIC SLOPE REGION. BULL. MUS. COMP. ZOOL., HARVARD UNIV., CAMBRIDGE, MA. 140(6):263-450.

  • Johnson, R.I. 1970a. The systematics and zoogeography of the Unionidae (Mollusca: Bivalvia) of the southern Atlantic slope region. Bulletin of the Museum of Comparative Zoology, Harvard University 140(6): 263-449.

  • Johnson, R.I. 1972b. Bibliography in: The Unionidae (Mollusca: Bivalve) of Peninsular Florida. Bulletin of the Florida State Museum Biological Sciences 16 (4):244-247.

  • Lee, H.G. 2006. Musings on a local specimen of Toxolasma paulum (I. Lea, 1840), the iridescent lilliput. The Shell-O-Gram 47(5):3-6.

  • Lefevre, G. and W.T. Curtis. 1912. Studies on the reproduction and artificial propogation of fresh-water mussels. Bulletin of the Bureau of Fisheries 30:102-201.

  • Mirarchi, R.E., et al. 2004a. Alabama Wildlife. Volume One: A Checklist of Vertebrates and Selected Invertebrates: Aquatic Mollusks, Fishes, Amphibians, Reptiles, Birds, and Mammals. University of Alabama Press: Tuscaloosa, Alabama. 209 pp.

  • Moyle, P. and J. Bacon. 1969. Distribution and abundance of molluscs in a fresh water environment. Journal of the Minnesota Academy of Science 35(2/3):82-85.

  • Pilarczyk, M.M., P.M. Stewart, D.N. Shelton, H.N. Blalock-Herod, and J.D. Williams. 2006. Current and Recent historical freshwater mussel assemblages in the Gulf Coastal Plains. Southeastern Naturalist, 5(2): 205-226.

  • Rafinesque, C.S. 1831. Continuation of a monograph of bivalve shells of the River Otto and other rivers of the western states. Brussels. 8pp.

  • Strayer, D. 1983. The effects of surface geology and stream size on freshwater mussel (Bivalvia, Unionidae) distribution in southeastern Michigan, U.S.A. Freshwater Biology 13:253-264.

  • Strayer, D.L. 1999a. Use of flow refuges by unionid mussels in rivers. Journal of the North American Benthological Society 18(4):468-476.

  • Strayer, D.L. and J. Ralley. 1993. Microhabitat use by an assemblage of stream-dwelling unionaceans (Bivalvia) including two rare species of Alasmidonta. Journal of the North American Benthological Society 12(3):247-258.

  • Turgeon, D.D., J.F. Quinn, Jr., A.E. Bogan, E.V. Coan, F.G. Hochberg, W.G. Lyons, P.M. Mikkelsen, R.J. Neves, C.F.E. Roper, G. Rosenberg, B. Roth, A. Scheltema, F.G. Thompson, M. Vecchione, and J.D. Williams. 1998. Common and scientific names of aquatic invertebrates from the United States and Canada: Mollusks. 2nd Edition. American Fisheries Society Special Publication 26, Bethesda, Maryland: 526 pp.

  • Van der Schalie, H. 1938a. The naiad fauna of the Huron River in southeastern Michigan. Miscellaneous Publication of the Museum of Zoology, University of Michigan 40:7-78.

  • Watters, G.T. 1992a. Unionids, fishes, and the species-area curve. Journal of Biogeography 19:481-490.

  • Williams, J. D., A. E. Bogan, R. S. Butler, K. S. Cummings, J. T. Garner, J. L. Harris, N. A. Johnson, and G. T. Watters. 2017. A revised list of the freshwater mussels (Mollusca: Bivalvia: Unionida) of the United States and Canada. Freshwater Mollusk Biology and Conservation 20:33-58.

  • Williams, J. D., A. E. Bogan, and J. T Garner. 2008. Freshwater mussels of Alabama & the Mobile Basin in Georgia, Mississippi, & Tennessee. University of Alabama Press, Tuscaloosa, Alabama. 908 pages.

  • Williams, J.D. and R.S. Butler. 1994. Class Bivalvia, Order Unionoida, freshwater bivalves. Pages 53-128, 740-742 in M. Deyrup and R. Frantz (eds.) Rare and Endangered Biota of Florida. Volume 4. Invertebrates. University Press of Florida, Gainesville, Florida. 798 pp.

  • Williams, J.D. and R.S. Butler. Freshwater mussels. Vol. 6, Invertebrates. R Frantz, ed. Rare and endangered biota of Florida. FL Committee on Rare and Endangered Plants and Animals, Univ. Presses of FL. In press.

  • Williams, J.D., M.L. Warren, Jr., K.S. Cummings, J.L. Harris, and R.J. Neves. 1993b. Conservation status of freshwater mussels of the United States and Canada. Fisheries 18(9): 6-22.

  • Williams, James D., Arthur Bogan, Robert Butler, Kevin Cummings, Jeffrey Garner, John Harris, Nathan Johnson and G.Thomas Watters. 2017. A  Revised List of the Freshwater Mussels (Mollusca: Bivalvia: Unionida) of the United States and Canada. Freshwater Mollusk Biology and Conservation 20:33-58

  • van der Schalie, H. 1940. The naiad fauna of the Chipola River in northwestern Florida. Lloydia 3(3):191-208.

References for Watershed Distribution Map
  • Brim Box, J. and J.D. Williams. 2000. Unionid mollusks of the Apalachicola Basin in Alabama, Florida, and Georgia. Alabama Museum of Natural History Bulletin, 21: 1-143.

  • Williams, J.D., A.E. Bogan, and J.T. Garner. 2008. Freshwater Mussels of Alabama & the Mobile Basin in Georgia, Mississippi & Tennessee. University of Alabama Press: Tuscaloosa, Alabama. 908 pp.

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http://www.natureserve.org/library/birdDistributionmapsmetadatav1.pdf.

Full metadata for the Mammal Range Maps of North America is available at:
http://www.natureserve.org/library/mammalsDistributionmetadatav1.pdf.

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