Utterbackia peggyae - (R. I. Johnson, 1965)
Florida Floater
Taxonomic Status: Accepted
Related ITIS Name(s): Anodonta peggyae Johnson, 1965 (TSN 79950) ;Utterbackia peggyae (R. I. Johnson, 1965) (TSN 568433)
Unique Identifier: ELEMENT_GLOBAL.2.112700
Element Code: IMBIV55020
Informal Taxonomy: Animals, Invertebrates - Mollusks - Freshwater Mussels
 
Kingdom Phylum Class Order Family Genus
Animalia Mollusca Bivalvia Unionoida Unionidae Utterbackia
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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: Utterbackia peggyae
Taxonomic Comments: Generic placement is based on the work of Hoeh (1990; 1991) and Hoeh et al. (1995). Electrophoretic evidence confirms that Utterbackia peggyae represents two species: Utterbackia peggyae and Utterbackia peninsularis (Bogan and Hoeh, 1994). Bogan and Hoeh (1995) split Utterbackia peninsularis from Utterbackia peggyae based on allozymes and stomach anatomy. This species was placed in the newly elevated genus Utterbackia by Hoeh (1990). Recently, Zanatta et al. (2007) supported the monophyly of both Pyganodon and Utterbackia using mutation coding of allozyme data, but also resolved the Eurasian Anodonta cygnea to Pyganodon, Utterbackia, and North American Anodonta; indicating futher phylogenetic analysis of the Anodontinae is required including both North American and Eurasian species.
Conservation Status
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NatureServe Status

Global Status: G3
Global Status Last Reviewed: 15Jan2014
Global Status Last Changed: 25Nov1996
Rounded Global Status: G3 - Vulnerable
Reasons: This species has a moderately small range overall but presumably maintains stable populations, has broad habitat tolerances, and is better able to withstand multiple threats to freshwater habitats than are many unionid mussels.
Nation: United States
National Status: N3 (11Jul2005)

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 (S1), Florida (S3), Georgia (S2)

Other Statuses

American Fisheries Society Status: Currently Stable (01Jan1993)

NatureServe Global Conservation Status Factors

Range Extent: 1000-20,000 square km (about 400-8000 square miles)
Range Extent Comments: Although formerly believed to occur from the Suwannee River system south to the Hillsborough River system (Johnson, 1965; 1972), these records were subsequently recognized as Utterbackia peninsularis, which is restricted to peninsular Florida (Bogan and Hoeh, 1995). U. peggyae is an Apalachicolan regional endemic species distributed from the Escambia to St. Marks rivers on the Gulf slope, including the Ochlockonee River drainage in Florida and Georgia (Williams et al., 2008). It is apparently absent from a few of the minor drainages (e.g., Ecofina Creek.). Found in Florida, southern Georgia, and southern Alabama. In his original description, Johnson (1965) reported that the species ranged from the Choctowhatchee to Hillsborough Rivers, but Heard (1979) also included the Yellow River in Florida. Butler (1989) extended the distribution to include the Escambia River system. Brim Box and Williama (2000) located 31 historicc records from 21 sites on the Apalachicola Basin of Georgia and Florida including the mainstem of the Chipola and Flint Rivers and a single record from Mosquito Creek (Apalachicola River tributary) in Gadson Co., Florida; as well as 19 of 324 recent sites surveyed. Blalock-Herod et al. (2005) listed 8 historic sites (resurveyed 3 and did not find any) and 4 new sites in the Choctawhatchee River drainage of Alabama and Florida. In southwestern Georgia, it is found in about a dozen counties in the Flint and Apalachicola rivers (historic in the Chipola River) (GA NHP, pers. comm., 2006).

Area of Occupancy: 501-12,500 4-km2 grid cells
Area of Occupancy Comments: Linear occupancy is 200-5000 km.

Number of Occurrences: 6 - 80
Number of Occurrences Comments: Before being divided into Utterbackia peggyae and U. peninsularis, it was known from approximately 28 localities, all but 2 or 3 of which are in Florida (see Johnson, 1972); 50% are in the Chipola and Ochlockonee rivers, but Butler (1989) included some historical records from the Escambia River drainage in Santa Rosa Co., Florida. Because this is a recently recognized species, historical records in the literature may be confused with U. imbecillis. Brim Box and Williams (2000) documented this species at 19 of 324 sites surveyed in the Apalachicola basin of Georgia and Florida, including the main channel and one tributary of the Apalachicola River, and in the main channel, tributaries, and one impoundment (Lake Blackshear) of the Flint River system (including southwestern Georgia) but not in the Chipola drainage where it was known historically. Blalock-Herod et al. (2005) listed 8 historic sites (resurveyed 3 of 8 in Florida and Alabama and did not find any) and 4 new sites in the Choctawhatchee River drainage (2 on the mainstem and one in Pine Log Creek in Florida; plus one off the Pea River in Alabama). Although Williams et al. (2008) claim it is found only in the Choctawhatchee River drainage and headwaters of the Chipola River in Alabama with Yellow and Escambia River drainage occurrences just over the border in Florida only, Pilarczyk et al. (2006) report recent collections of this species in Flat Creek (Choctawhatchee drainage), Yellow River (Yellow River drainage), and the West Fork Choctawhatchee River, southeastern Alabama. In Georgia, it is found in the Flint and Apalachicola Rivers of southwestern Georgia (historic in the Chipola River) in about a dozen counties (GA NHP, pers. comm., 2006).

Population Size: 10,000 - 1,000,000 individuals
Population Size Comments: This species is not uncommon in appropriate habitat throughout its range. Brim Box and Williams (2000) documented this species at 19 of 324 sites (total 32 live specimens and 69 shells) surveyed in the Apalachicola Basin including the main channel and one tributary of the Apalachicola River, and in the main channel, tributaries, and one impoundment (Lake Blackshear) of the Flint River system but not in the Chipola drainage where it was known historically. In 1999, this species was found to comprise 0.03% (relative abundance) of the 14,873 mussels collected in surveys of 46 sites in 12 tributary streams of the lower Flint River Basin, Georgia (Gagnon et al., 2006). In a 2004 survey of 24 sites in the Choctawhatchee, Yellow, and Conecuh-Escambia River drainages in southern Alabama, Pilarczyk et al. (2006) found this species at three sites in low numbers.

Number of Occurrences with Good Viability/Integrity: Unknown

Overall Threat Impact: High - medium
Overall Threat Impact Comments: Suitability to lacustrine habitats precludes a major threat from dams. Presumably responds negatively to habitat degradation and other basic threats (e.g., runoff, municipal and industrial pollution etc.).

Short-term Trend: Relatively Stable (<=10% change)
Short-term Trend Comments: It is difficult to determine due to past confusion with Utterbackia imbecillis and U. peninsularis, from which it was recently taxonomically split. Considering the habitat and present status, this species is probably doing as well as historically and possibly better considering the preponderance of man-made habitat (e.g., reservoirs).

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

Intrinsic Vulnerability: Moderately vulnerable to not intrinsically vulnerable.
Intrinsic Vulnerability Comments: Freshwater mussels are inherently vulnerable to threats from siltation, pollution, eutrophication, channelization, impoundment, collection, drought and water withdrawal, competiton from invasive non-native mussels, and changes to larval host fish populations. However, this species appears to be relatively tolerant of non-severe changes.

Environmental Specificity: Moderate to broad.
Environmental Specificity Comments: This species inhabits sandy or muddy substrates of reservoirs, ponds, lakes and slow-moving streams (Heard, 1979) and is tolerant of impoundment (Johnson, 1965; Brim Box and Williams, 2000).

Other NatureServe Conservation Status Information

Inventory Needs: Survey suitable habitat in northern part of range (AL and GA portions of Escambia, Yellow, Choctawhatchee, Apalachicola, and Ochlockonee river drainages).

Protection Needs: Maintain high water and benthic habitat (substrate) qualities, as well as adequate flow regimes, throughout all occupied river systems. This may be partially accomplished via establishment of buffers and streamside management zones for all agricultural, silvicultural, mining, and developmental activities; protection of floodplain forests and adjoining upland habitat is paramount. Best management practices to follow include employing forestry practices that cause minimal soil erosion; preventing access of livestock to natural surface waters and drains; situating roads at least 0.25 mi. (0.4 km) from heads of all tributaries, even more on steep slopes; using silt fencing and vegetation to control runoff and siltation at all stream crossings, especially during construction and maintenance; using and maintaining sewer systems rather than septic tanks and stream-dumping for management of wastewater; and avoiding use of agricultural pesticides on porous soils near streams. Prevent damming, dredging, and pollution throughout drainages, but especially near recorded sites. Remove existing dams, but with great care to limit downstream sedimentation. Limit withdrawal of surface and subterranean waters as necessary to maintain normal stream flows, especially during drought. Prevent or limit establishment of invasive species (including zebra mussel, Dreissena polymorpha) to the extent possible. Where appropriate, protect populations through acquisitions and easements over streamside lands by working with government agencies and conservation organizations.

Distribution
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Global Range: (1000-20,000 square km (about 400-8000 square miles)) Although formerly believed to occur from the Suwannee River system south to the Hillsborough River system (Johnson, 1965; 1972), these records were subsequently recognized as Utterbackia peninsularis, which is restricted to peninsular Florida (Bogan and Hoeh, 1995). U. peggyae is an Apalachicolan regional endemic species distributed from the Escambia to St. Marks rivers on the Gulf slope, including the Ochlockonee River drainage in Florida and Georgia (Williams et al., 2008). It is apparently absent from a few of the minor drainages (e.g., Ecofina Creek.). Found in Florida, southern Georgia, and southern Alabama. In his original description, Johnson (1965) reported that the species ranged from the Choctowhatchee to Hillsborough Rivers, but Heard (1979) also included the Yellow River in Florida. Butler (1989) extended the distribution to include the Escambia River system. Brim Box and Williama (2000) located 31 historicc records from 21 sites on the Apalachicola Basin of Georgia and Florida including the mainstem of the Chipola and Flint Rivers and a single record from Mosquito Creek (Apalachicola River tributary) in Gadson Co., Florida; as well as 19 of 324 recent sites surveyed. Blalock-Herod et al. (2005) listed 8 historic sites (resurveyed 3 and did not find any) and 4 new sites in the Choctawhatchee River drainage of Alabama and Florida. In southwestern Georgia, it is found in about a dozen counties in the Flint and Apalachicola rivers (historic in the Chipola River) (GA NHP, pers. comm., 2006).

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 County Help
State County Name (FIPS Code)
AL Dale (01045)*, Geneva (01061)
FL Escambia (12033), Gadsden (12039), Holmes (12059), Jackson (12063), Leon (12073), Okaloosa (12091), Santa Rosa (12113), Wakulla (12129), Washington (12133)
GA Baker (13007), Calhoun (13037), Clayton (13063), Crisp (13081), Decatur (13087), Dooly (13093)*, Fayette (13113), Grady (13131), Marion (13197)*, Meriwether (13199)*, Miller (13201), Pike (13231)*, Seminole (13253)*, Spalding (13255)*, Sumter (13261), Thomas (13275), Worth (13321)
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
03 Apalachee Bay-St. Marks (03120001)+, Upper Ochlockonee (03120002)+, Lower Ochlockonee (03120003)+, Middle Chattahoochee-Lake Harding (03130002), Upper Flint (03130005)+, Middle Flint (03130006)+, Kinchafoonee-Muckalee (03130007)+, Lower Flint (03130008)+, Ichawaynochaway (03130009)+, Spring (03130010)+, Apalachicola (03130011), Chipola (03130012)+, Yellow (03140103)+, Pensacola Bay (03140105), Upper Choctawhatchee (03140201), Pea (03140202)+, Lower Choctawhatchee (03140203)+, Escambia (03140305)+
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History
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Basic Description: A medium sized, thin-shelled, toothless freshwater mussel.
General Description: See Johnson (1965).
Diagnostic Characteristics: Larger and more inflated than congener, generally greener (darker green).
Reproduction Comments: Animals are dioecious with fairly slow growth to sexual maturity: possibly bradytictic (long-term brooder). The glochidial host is not known.
Ecology Comments: Fairly tolerant of some habitat degradation and impoundments.
Habitat Type: Freshwater
Non-Migrant: N
Locally Migrant: N
Long Distance Migrant: N
Mobility and Migration Comments: Adults are essentially sessile. About the only voluntary movement they make is to burrow deeper into the substrate (potential for this is good considering affinity for softer substrates). Some passive movement downstream may occur during high flows. Dispersal occurs while the glochidia are encysted on their host (probably a fish).
Riverine Habitat(s): BIG RIVER, Low gradient, MEDIUM RIVER, Pool
Lacustrine Habitat(s): Shallow water
Special Habitat Factors: Benthic
Habitat Comments: This species inhabits sandy or muddy substrates of reservoirs, ponds, lakes and slow-moving streams (Heard, 1979) and is tolerant of impoundment (Johnson, 1965; Brim Box and Williams, 2000).
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: 7.1 centimeters
Economic Attributes Not yet assessed
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Management Summary
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Biological Research Needs: Host fish determination and life history studies.
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: 15Jan2014
NatureServe Conservation Status Factors Author: Jackson, D. R. (2014); Cordeiro, J. (2009); Butler, R.S.; revised by M. Morrison (1998)
Element Ecology & Life History Edition Date: 07Mar2007
Element Ecology & Life History Author(s): Cordeiro, J. (2007); BUTLER, R.S. (1991)

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

References
Help
  • Blalock-Herod, H. N., J. J. Herod, J. D. Williams, B. N. Wilson, and S. W. McGregor. 2005. A historical and current perspective of the freshwater mussel fauna (Bivalvia: Unionidae) from the Choctawhatchee River drainage in Alabama and Florida. Bulletin of the Alabama Museum of Natural History 24:1-26.

  • Bogan, A. E., and W. R. Hoeh. 1995. Utterbackia peninsularis, a newly recognized freshwater mussel (Bivalvia: Unionidae: Anodontinae) from peninsular Florida, U.S.A. Walkerana 7 (17/18): 275-287.

  • Bogan, A.E. and W.R. Hoeh. 1995. Utterbackia peninsularis, a newly recognized freshwater mussel (Bivalvia: Unionidae: Anodontinae) from Peninsular Florida, U.S.A. Walkerana, 7(17/18): 275-287.

  • Butler, R.S. 1989. Distributional records for freshwater mussels (Bivalvia: Unionidae) in Florida and south Alabama, with zoogeographic and taxonomic notes. Walkerana, 3(10): 239-261.

  • 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.

  • Gagnon, P., W. Michener, M. Freeman, and J. Brim Box. 2006. Unionid habitat and assemblage composition in coastal plain tributaries of Flint River (Georgia). Southeastern Naturalist, 5(1): 31-52.

  • 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.

  • Hoeh, W. R., K. S. Frazer, E. Naranjo-Garcia, and R. J. Trdan. 1995. A phylogenetic perspective on the evolution of simultaneous hermaphroditism in a freshwater mussel clade (Bibalvia: Unionidae: UTTERBACKIA). Malacological Review 28:25-42.

  • Hoeh, W.R. 1990. Phylogenetic relationships among eastern North American Anodonta (Bivalvia: Unionidae). Malacological Review, 23: 63-82.

  • Hoeh, W.R. 1991. The evolution and consequences of simultaneous hermaphroditism in the freshwater mussel genus Utterbackia (Bivalvia: Unionidae). Ph.D. Dissertation, Biology, University of Michigan, Ann Arbor, Michigan. 97 pp.

  • Hoeh, W.R., K.S. Frazer, E. Naranjo-Garcia, and R.J. Trdan. 1995. A phylogenetic perspective on the evolution of simultaneous hermaphorditism in a freshwater mussel clade (Bivalvia: Unionidae: Utterbackia). Malacological Review, 28: 25-42.

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

  • Johnson, R.I. 1965. A hithero overlooked Anodonta (Mollusca: Unionidae) from the Gulf drainage of Florida. Breviora, 213: 1-7.

  • Johnson, R.I. 1972a. The Unionidae (Mollusca: Bivalvia) of peninsular Florida. Bulletin of the Florida State Museum of Biological Science 16(4): 181-249.

  • 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.

  • 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.

  • 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., R. S. Butler, G. L. Warren, and N. A. Johnson.  2014.  Freshwater Mussels of Florida.  University of Alabama Press, Tuscaloosa.  498 pp.

  • Williams, J. D., R. S. Butler, G. L. Warren, and N. A. Johnson.  2014a.  Freshwater Mussels of Florida.  University of Alabama Press, Tuscaloosa, Alabama. 498 pp.

  • 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.

  • Zanatta, D.T., A. Ngo, and J. Lindell. 2007a. Reassessment of the phylogenetic relationships among Anodonta, Pyganodon, and Utterbackia (Bivalvia: Unionoida) using mutation coding of allozyme data. Proceedings of the Academy of Natural Sciences of Philadelphia 156: 211-216.

References for Watershed Distribution Map
  • Biological Resources Division, USGS. 1997. Database of museum records of aquatic species. Compiled by J. Williams (USGS-BRD, Gainesville, FL).

  • Blalock-Herod, H.N., J.J. Herod, J.D. Williams, B.N. Wilson, and S.W. McGregor. 2005. A historical and current perspective of the freshwater mussel fauna (Bivalvia: Unionidae) from the Choctawhatchee River drainage in Alabama and Florida. Bulletin of the Alabama Museum of Natural History, 24: 1-26.

  • 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.

  • 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.

  • 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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Citation for Bird Range Maps of North America:
Ridgely, R.S., T.F. Allnutt, T. Brooks, D.K. McNicol, D.W. Mehlman, B.E. Young, and J.R. Zook. 2003. Digital Distribution Maps of the Birds of the Western Hemisphere, version 1.0. NatureServe, Arlington, Virginia, USA.

Acknowledgement Statement for Bird Range Maps of North America:
"Data provided by NatureServe in collaboration with Robert Ridgely, James Zook, The Nature Conservancy - Migratory Bird Program, Conservation International - CABS, World Wildlife Fund - US, and Environment Canada - WILDSPACE."

Citation for Mammal Range Maps of North America:
Patterson, B.D., G. Ceballos, W. Sechrest, M.F. Tognelli, T. Brooks, L. Luna, P. Ortega, I. Salazar, and B.E. Young. 2003. Digital Distribution Maps of the Mammals of the Western Hemisphere, version 1.0. NatureServe, Arlington, Virginia, USA.

Acknowledgement Statement for Mammal Range Maps of North America:
"Data provided by NatureServe in collaboration with Bruce Patterson, Wes Sechrest, Marcelo Tognelli, Gerardo Ceballos, The Nature Conservancy-Migratory Bird Program, Conservation International-CABS, World Wildlife Fund-US, and Environment Canada-WILDSPACE."

Citation for Amphibian Range Maps of the Western Hemisphere:
IUCN, Conservation International, and NatureServe. 2004. Global Amphibian Assessment. IUCN, Conservation International, and NatureServe, Washington, DC and Arlington, Virginia, USA.

Acknowledgement Statement for Amphibian Range Maps of the Western Hemisphere:
"Data developed as part of the Global Amphibian Assessment and provided by IUCN-World Conservation Union, Conservation International and NatureServe."

NOTE: Full metadata for the Bird Range Maps of North America is available at:
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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