Ptychobranchus subtentus - (Say, 1825)
Fluted Kidneyshell
Synonym(s): Ptychobranchus subtentum (Say, 1825)
Taxonomic Status: Accepted
Related ITIS Name(s): Ptychobranchus subtentum (Say, 1825) (TSN 80162)
Unique Identifier: ELEMENT_GLOBAL.2.118056
Element Code: IMBIV38050
Informal Taxonomy: Animals, Invertebrates - Mollusks - Freshwater Mussels
 
Kingdom Phylum Class Order Family Genus
Animalia Mollusca Bivalvia Unionoida Unionidae Ptychobranchus
Genus Size: B - Very small genus (2-5 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: Ptychobranchus subtentum
Taxonomic Comments: Lee (2008) correctly notes that in keeping with the ICZN and proper nomenclatural gender, this species should be rendered Ptychobranchus subtentus.
Conservation Status
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NatureServe Status

Global Status: G2
Global Status Last Reviewed: 14May2009
Global Status Last Changed: 09Nov2005
Rounded Global Status: G2 - Imperiled
Reasons: Currently this species is known from ten populations; range has been drastically reduced presumably due to loss of suitable habitat and although it is still declining today, most of the range reduction occurred historically. Remaining populations fragmented and only one is truly viable in the long-term.
Nation: United States
National Status: N2 (09Nov2005)

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 (SX), Kentucky (S1), Tennessee (S2), Virginia (S2)

Other Statuses

U.S. Endangered Species Act (USESA): LE: Listed endangered (26Sep2013)
U.S. Fish & Wildlife Service Lead Region: R4 - Southeast
IUCN Red List Category: NT - Near threatened
American Fisheries Society Status: Special Concern (01Jan1993)

NatureServe Global Conservation Status Factors

Range Extent: 250-1000 square km (about 100-400 square miles)
Range Extent Comments: The fluted kidneyshell is restricted to the Cumberland (in Kentucky and Tennessee) and Tennessee (in Alabama, Tennessee, and Virginia) River systems. Historically, this species occurred in the Cumberland River main stem from below Cumberland Falls in southeastern Kentucky downstream through the Tennessee portion of the river to the vicinity of the Kentucky-Tennessee State line. In the Tennessee River main stem it occurred from eastern Tennessee to western Tennessee. Records are known from approximately 16 Cumberland River tributaries (Horse Lick Creek, Middle Fork Rockcastle River, Rockcastle River, Buck Creek, Rock Creek, Kennedy Creek, Little South Fork, Big South Fork, Pitman Creek, Otter Creek, Wolf River, West Fork Obey River, Obey River, Caney Fork, South Harpeth River, and West Fork Red River). In addition, it is known from 21 Tennessee River system tributaries, including the South Fork Powell River, Powell River, Indian Creek, Little River, Clinch River, Copper Creek, Big Moccasin Creek, North Fork Holston River, Middle Fork Holston River, South Fork Holston River, Holston River, Nolichucky River, West Prong Little Pigeon River, Little Tennessee River, Hiwassee River, Flint River, Limestone Creek, Elk River, Shoal Creek, Duck River, and BuffaloRiver. Undocumented, but now lost, populations assuredly occurred in other Cumberlandian Region tributary systems (USFWS, 2001). Also from upper Cumberland and Tennessee Rivers, ranging downstream to Muscle Shoals in the Tennessee River but not reported from Alabama since impoundment of Tennessee River (Mirarchi et al., 2004). Currently, it is limited to nine streams in the Cumberland River system and seven streams in the Tennessee River system.

Area of Occupancy: 126-2,500 4-km2 grid cells
Area of Occupancy Comments:  

Number of Occurrences: 6 - 20
Number of Occurrences Comments: Currently, it is limited to nine streams in the Cumberland River system (six isolated populations) and seven streams (four isolated populations) in the Tennessee River system. Cumberland River system tributaries with extant populations include the Middle Fork Rockcastle River, Horse Lick Creek, Buck Creek, Rock Creek, Kennedy Creek, Little South Fork, Big South Fork, Wolf River, and West Fork Obey River. Presently, this species is also known in the Powell River, Indian Creek, Little River, Clinch River, Copper Creek, North Fork Holston River, and Middle Fork Holston River in the Tennessee River system (USFWS, 2001; Parmalee and Bogan, 1998). It was reported recently in the upper Clinch (Jones et al., 2001) and Copper Creek (Upper Clinch drainage) in Virginia (Fraley and Ahlstedt, 2000; Hanlon et al., 2009); and upper South Fork Holston (Stansbery and Clench, 1978). Jones and Neves (2007) summarize distribution in the upper North Fork Holston River (Smyth and Bland Cos., Virginia) as rkm 151.6 to 159.0.

Population Size: Unknown
Population Size Comments: Experienced collectors have been finding four or fewer specimens per site (USFWS, 1999).

Number of Occurrences with Good Viability/Integrity: Very few (1-3)
Viability/Integrity Comments: Barr et al. (1994) determined (based on 1981 survey data) that viable populations exist in the Clinch, Powell, and North Fork Holston Rivers. Only in the Clinch River system in Hancock Co., Tennessee (Parmalee and Bogan, 1998) is a population of the fluted kidneyshell known to be stable and viable, but in a relatively short reach of river primarily in the vicinity of the Tennessee-Virginia State line (USFWS, 1999; 2001).

Overall Threat Impact: Very high - high
Overall Threat Impact Comments: The decline of the fluted kidneyshell in the Cumberlandian Region and other mussel species in the eastern United States is primarily the result of habitat loss and degradation. These losses have been well documented for over 130 years. Chief among the causes of decline are impoundments, stream channel alterations, water pollution, and sedimentation. Instream gravel mining has also been implicated in the destruction of mussel populations. Heavy-metal rich drainage from coal mining and associated sedimentation have adversely impacted upper Cumberland River system streams with diverse historical mussel faunas. Sediment from the upper Clinch River, where the largest population of the fluted kidneyshell remains, was found to be toxic to juvenile mussels (USFWS, 1999; 2001).

Other threats include: overutilization for commercial, recreational, scientific, or educational purposes (minimal threat: not a commercially valuable species, but may be increasingly sought by collectors with its increasing rarity); disease or predation (disease largely unknown; predation is a localized threat); inadequacy of existing regulatory mechanisms (Alabama, Kentucky, Tennessee, and Virginia prohibit the taking of mussels for scientific purposes without a State collecting permit, however, enforcement of this permit requirement is difficult) (USFWS, 2001).

Short-term Trend: Decline of 30-50%
Short-term Trend Comments: The species is extirpated from Alabama. It is extirpated (eliminated) from both the Cumberland and Tennessee River main stems, the fluted kidneyshell has also been eliminated from about three-fifths of the total number of streams from which it was historically known but much of this decline did not occur in recent times, although it is declining today. In Tennessee, it is now extirpated from the main Holston and Tennessee Rivers, Little Tennessee, Duck, Buffalo, Obey, Caney Fork, and Harpeth Rivers (Parmalee and Bogan, 1998). The certainty that the fluted kidneyshell occurred in other streams within its historic range increases the percentage of lost habitat and populations, thus making its present status that much more imperilled (USFWS, 2001).

Long-term Trend: Decline of 70-90%
Long-term Trend Comments: it was fairly widespread historically and common in many Cumberlandian Region streams based on collections made in the early 1900s. Its decline in certain streams may have begun before European colonization. Extirpation from numerous streams within its historical range indicates that substantial population losses have occurred (USFWS, 1999; 2001). Presence in certain streams, particularly in the middle Tennessee River system, is known only by records from aboriginal "kitchen middens" (Parmalee and Bogan, 1998). It was historically reported from the upper Elk River, Tennessee (Isom et al., 1973). Historically in Alabama, it occurred in the Tennessee River downstream to Muscle Shoals (Mirarchi et al., 2004; Williams et al., 2008) as recorded by Ortmann (1925), but it has not been seen since.

Intrinsic Vulnerability: Highly vulnerable
Intrinsic Vulnerability Comments: The remaining populations of the fluted kidneyshell are generally small and geographically isolated. The patchy distribution pattern of populations in short river reaches makes them much more susceptible to extirpation from single catastrophic events, such as toxic chemical spills. It is likely that some populations of the fluted kidneyshell are below the effective population size required to maintain long-term genetic and population viability (USFWS, 2003).

Environmental Specificity: Narrow. Specialist or community with key requirements common.
Environmental Specificity Comments: This species inhabits small to medium rivers in areas with swift current or riffles, although a few populations were recorded from larger rivers in shoal areas. It is often found embedded in sand, gravel, and cobble substrates (Gordon and Layzer, 1989). It requires flowing, well-oxygenated waters and is largely intolerant of impoundment.

Other NatureServe Conservation Status Information

Inventory Needs: Revisit sites to determine population density.

Protection Needs: Conservation of existing populations.

Distribution
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Global Range: (250-1000 square km (about 100-400 square miles)) The fluted kidneyshell is restricted to the Cumberland (in Kentucky and Tennessee) and Tennessee (in Alabama, Tennessee, and Virginia) River systems. Historically, this species occurred in the Cumberland River main stem from below Cumberland Falls in southeastern Kentucky downstream through the Tennessee portion of the river to the vicinity of the Kentucky-Tennessee State line. In the Tennessee River main stem it occurred from eastern Tennessee to western Tennessee. Records are known from approximately 16 Cumberland River tributaries (Horse Lick Creek, Middle Fork Rockcastle River, Rockcastle River, Buck Creek, Rock Creek, Kennedy Creek, Little South Fork, Big South Fork, Pitman Creek, Otter Creek, Wolf River, West Fork Obey River, Obey River, Caney Fork, South Harpeth River, and West Fork Red River). In addition, it is known from 21 Tennessee River system tributaries, including the South Fork Powell River, Powell River, Indian Creek, Little River, Clinch River, Copper Creek, Big Moccasin Creek, North Fork Holston River, Middle Fork Holston River, South Fork Holston River, Holston River, Nolichucky River, West Prong Little Pigeon River, Little Tennessee River, Hiwassee River, Flint River, Limestone Creek, Elk River, Shoal Creek, Duck River, and BuffaloRiver. Undocumented, but now lost, populations assuredly occurred in other Cumberlandian Region tributary systems (USFWS, 2001). Also from upper Cumberland and Tennessee Rivers, ranging downstream to Muscle Shoals in the Tennessee River but not reported from Alabama since impoundment of Tennessee River (Mirarchi et al., 2004). Currently, it is limited to nine streams in the Cumberland River system and seven streams in the Tennessee River system.

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 ALextirpated, KY, TN, VA

Range Map
No map available.


U.S. Distribution by County Help
State County Name (FIPS Code)
AL Lauderdale (01077)*, Limestone (01083)*, Madison (01089)*
KY Christian (21047)*, Jackson (21109), Laurel (21125)*, McCreary (21147), Pulaski (21199), Rockcastle (21203), Russell (21207)*, Todd (21219)*, Wayne (21231), Whitley (21235)*
TN Bedford (47003), Claiborne (47025), Fentress (47049)*, Franklin (47051)*, Grainger (47057), Greene (47059), Hancock (47067), Marshall (47117), Overton (47133)*, Pickett (47137)*
VA Lee (51105), Russell (51167), Scott (51169), Smyth (51173), Tazewell (51185), Washington (51191)
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
05 Upper Cumberland (05130101)+, Rockcastle (05130102)+, Upper Cumberland-Lake Cumberland (05130103)+, South Fork Cumberland (05130104)+, Obey (05130105)+, Caney (05130108)*, Harpeth (05130204)*, Lower Cumberland (05130205)*, Red (05130206)+*
06 North Fork Holston (06010101)+, South Fork Holston (06010102)+, Holston (06010104), Pigeon (06010106), Lower French Broad (06010107), Nolichucky (06010108)+, Lower Little Tennessee (06010204)*, Upper Clinch (06010205)+, Powell (06010206)+, Middle Tennessee-Chickamauga (06020001)*, Guntersville Lake (06030001)*, Wheeler Lake (06030002)+*, Upper Elk (06030003)+, Lower Elk (06030004)+*, Pickwick Lake (06030005)+*, Upper Duck (06040002)+, Lower Duck (06040003)*, Buffalo (06040004)*
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History
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Basic Description: a freshwater mussel
General Description: Relatively large mussel. Shape of the shell is roughly oval elongate, and solid, relatively heavy valves are moderately inflated. A series of flutings (corrugations) characterize the posterior slope. Shell texture is smooth and somewhat shiny in young specimens, becoming more dull with age. Shell color is greenish yellow, becoming brownish with age, with several broken, wide green rays. Internally, the pseudocardinal teeth are stumpy and triangular in shape. Lateral teeth are heavy. Color of the nacre is bluish white to dull white with a wash of salmon in the beak cavity (Parmalee and Bogan, 1998).
Reproduction Comments: This species is unusual in that outer portion of a brooding female's outer gills folded in a curtain-like fashion (characteristic of the genus). It is thought to have a late summer or early fall fertilization period with glochidia incubating overwinter. Glochidia are released the following spring or early summer as conglutinates. Conglutinates are shaped like insect larvae, and have an adhesive end that sticks to silt-free stones on the stream bottom. Host fishes include: Etheostoma obeyense (barcheek dareter), Etheostoma rufilineatum (redline darter), Etheostoma flabellare (fantail darter), Etheostoma caeruleum (redline darter), Cottus carolinae (banded sculpin) (Luo and Layzer, 1993).
Habitat Type: Freshwater
Non-Migrant: N
Locally Migrant: N
Long Distance Migrant: N
Riverine Habitat(s): CREEK, High gradient, Riffle, SPRING/SPRING BROOK
Special Habitat Factors: Benthic
Habitat Comments: This species inhabits small to medium rivers in areas with swift current or riffles, although a few populations were recorded from larger rivers in shoal areas. It is often found embedded in sand, gravel, and cobble substrates (Gordon and Layzer, 1989). It requires flowing, well-oxygenated waters.
Adult Food Habits: Detritivore
Immature Food Habits: Parasitic
Adult Phenology: Diurnal
Length: 13 centimeters
Economic Attributes Not yet assessed
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Management Summary
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Stewardship Overview: This species was listed as a federal candidate species in the U.S. in 2004 (USFWS, 2001).
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: 14May2009
NatureServe Conservation Status Factors Author: Cordeiro, J.
Element Ecology & Life History Edition Date: 01Mar2007
Element Ecology & Life History Author(s): Cordeiro, J.

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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  • Fraley, S.J. and S.A. Ahlstedt. 2000. The recent decline of the native mussels (Unionidae) of Copper Creek, Russell and Scott Counties, Virginia. Pages 189-195 in R.A. Tankersley, D.I. Warmolts, G.T. Watters, B.J. Armitage, P.D. Johnson, and R.S. Butler (eds.). Freshwater Mollusk Symposia Proceedings. Ohio Biological Survey, Columbus, Ohio. 274 pp.

  • Gordon, M.E. and J.B. Layzer. 1989. Mussels (Bivalvia: Unionoidea) of the Cumberland River review of life histories and ecological relationships. U.S. Fish and Wildlife Service Biological Report, 89(15): 1-99.

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

  • Isom, B.G., P. Yokley, Jr., and C.H. Gooch. 1973. Mussels of Elk River Basin in Alabama and Tennessee- 1965-1967. American Midland Naturalist 89(2):437-442.

  • Jones, J.W. and R.J. Neves. 2007. Freshwater mussel status: Upper North Fork Holston River, Virginia. Northeastern Naturalist, 14(3): 471-480.

  • Jones, J.W., R.J. Neves, M.A. Patterson, C.R. Good, and A. DiVittorio. 2001. A status survey of freshwater mussel populations in the upper Clinch River, Tazewell County, Virginia. Banisteria, 17: 20-30.

  • Lee, H. G. 2008. Book Review: Freshwater mussels of Alabama and the Mobile Basin in Georgia, Mississippi and Tennessee, by J. D. William, A. E. Bogan, and J.T. Garner. The Nautilus 122(4): 261-263.

  • Lee, H. G. 2008. Book Review: Freshwater mussels of Alabama and the Mobile Basin in Georgia, Mississippi and Tennessee, by J. D. William, A. E. Bogan, and J.T. Garner. The Nautilus 122(4):261-263.

  • 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.

  • Loomis, R., T. Beaulieu, V. Glenn, C. Mansfield, J. Cajka, and S. Casey. 2013b. Economic analysis of critical habitat designation for the fluted kidneyshell and slabside pearlymussel. Final report. Report prepared for the U.S. Fish and Wildlife Service. RTI International, Research Triangle Park, North Carolina. 112 pages.

  • Luo, M. and J.B. Layzer. 1993. Host fish of three freshwater mussels. (Abstract). Page 182 in K.S. Cummings, A.C. Buchanan, and L.M. Koch. (eds.). Conservation and Management of Freshwater Mussels. Proceedings of a UMRCC Symposium, 12-14 October 1992, St. Louis, Missouri. Upper Mississippi River Conservation Committee, Rock Island, Illinois. 189 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.

  • Ortmann, A.E. 1925. The naiad fauna of the Tennessee River system below Walden Gorge. The American Midland Naturalist, 9(7): 321-371.

  • Parmalee, P.W. and A.E. Bogan. 1998. The freshwater mussels of Tennessee. University of Tennessee Press, Knoxville, Tennesee. 328 pp.

  • Stansbery, D. H. and W. J. Clench. 1977 [1978]. The Pleuroceridae and Unionidae of the Upper South Fork Holston River in Virginia. Bulletin of the American Malacological Union 1977:75-79.

  • 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.

  • U.S. Fish and Wildlife Service (USFWS). 1999. Candidate and listing priority assignment forms.

  • U.S. Fish and Wildlife Service. 2012e. Endangered and threatened wildlife and plants; endangered species status for the fluted kidneyshell and slabside pearlymussel and designation of critical habitat; proposed rule. Federal Register 77(193):60804-60882.

  • U.S. Fish and Wildlife Service. 2013g. Endangered and threatened wildlife and plants; endangered species status for the fluted kidneyshell and slabside pearlymussel. Final rule. Federal Register 78(187):59269-59287.

  • U.S. Fish and Wildlife Service. 2013h. Endangered and threatened wildlife and plants; designation of critical habitat for the fluted kidneyshell and slabside pearlymussel. Final rule. Federal Register 78(187):59556-59620.

  • 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, 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., 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., 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.

References for Watershed Distribution Map
  • Barr, W.C., S.A. Ahlstedt, G.D. Hickman, and D.M. Hill. 1993-1994. Cumberlandian mollusk conservation program. Activity 8: Analysis of macrofauna factors. Walkerana 7(17/18):159-224.

  • Cicerello, R.R. and G.A. Schuster. 2003. A guide to the freshwater mussels of Kentucky. Kentucky State Nature Preserves Commission Scientific and Technical Series 7:1-62.

  • Hanlon, S.D., M.A. Petty, and R.J. Neves. 2009. Status of native freshwater mussels in Copper Creek, Virginia. Southeastern Naturalist 8(1):1-18.

  • Mirarchi, R.E., J.T. Garner, M.F. Mettee, and P.E. O'Neil. 2004b. Alabama wildlife. Volume 2. Imperiled aquatic mollusks and fishes. University of Alabama Press, Tuscaloosa, Alabama. xii + 255 pp.

  • Parmalee, P.W. and A.E. Bogan. 1998. The Freshwater Mussels of Tennessee. University of Tennessee Press: Knoxville, Tennessee. 328 pp.

  • U.S. Fish and Wildlife Service (USFWS). 2001. Candidate and listing priority assignment form- Ptychobranchus subtentum. U.S. Fish and Wildlife Service, Ashville, North Carolina. 15 pp.

  • 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 data on website including State Distribution, Watershed, and Reptile Range maps:
NatureServe. 2018. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available http://explorer.natureserve.org. (Accessed:

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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