Pleuronaia dolabelloides - (I. Lea, 1840)
Slabside Pearlymussel
Other English Common Names: Slab-sided Naiad, Slab-sided Pearly Mussel
Taxonomic Status: Accepted
Related ITIS Name(s): Lexingtonia dolabelloides conradi (Vanatta) (TSN 80259) ;Lexingtonia dolabelloides dolabelloides (Lea, 1840) (TSN 80258) ;Lexingtonia dolabelloides (I. Lea, 1840) (TSN 80257)
Unique Identifier: ELEMENT_GLOBAL.2.106952
Element Code: IMBIV25010
Informal Taxonomy: Animals, Invertebrates - Mollusks - Freshwater Mussels
 
Kingdom Phylum Class Order Family Genus
Animalia Mollusca Bivalvia Unionoida Unionidae Pleuronaia
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: Lexingtonia dolabelloides
Taxonomic Comments: Lexingtonia was based on the anatomical characters of "Unio subplanus Conrad, 1837" (see Ortmann, 1914). Subsequently, Ortmann (1918) included dolabelloides in this genus. There are only two species formerly classified in Lexingtonia, representing a rather unique, disjunct geographic distribution (Cumberlandian region vs. coastal drainage of Virginia). Although similar to and formerly classified in Pleurobema, Lexingtonia (now Pleuronaia) is distinguished from the latter by its red, subcylindrical glochidial conglutinates and wavy beak sculpture. Pleuronaia dolabelloides has historically been treated as a member of the genus Fusconaia despite differences from other members of the genus (Ortmann, 1917; 1918). Bogan et al. (unpublished) found Lexingtonia subplana is synonymous with Fusconaia masoni and since L. subplana is the type species for the genus, Lexingtonia becomes a synonym of Fusconaia. The next available generic name for barnesiana and dolabelloides is Pleuronaia Frierson, 1927. Pleurobema gibberum was also found to belong to the Pleuronaia clade (see Williams et al., 2008). Pleuronaia dolabelloides exibits ecophenotypic variation. Shell inflation increases progressively as a function of increasing stream size. Compressed forms found in creeks and smaller rivers were designated Pleuronaia dolabelloides conradi (Vanatta, 1915); inflated dolabelloides s.s. were found in larger habitats (see Ortmann, 1918). Ortmann (1920) determined the "two forms pass gradually into each other". Although previously used in a subspecific context, such designation is not consistent with current systematic interpretations
Conservation Status
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NatureServe Status

Global Status: G2
Global Status Last Reviewed: 14May2009
Global Status Last Changed: 29Aug2000
Rounded Global Status: G2 - Imperiled
Reasons: This species has been eliminated from at least three-fifths of the total number of streams where it was historically recorded. It is experiencing recent and continuing sharp declines in occurrences; with the majority of surviving individuals apparently restricted to two to three populations. Continuing long-term viability at all extant occurrences is questionable.
Nation: United States
National Status: N2 (29Aug2000)

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), Kentucky (SX), Mississippi (S1), North Carolina (SX), 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: EN - Endangered
American Fisheries Society Status: Threatened (01Jan1993)

NatureServe Global Conservation Status Factors

Range Extent: 1000-5000 square km (about 400-2000 square miles)
Range Extent Comments: The species is restricted to the Cumberland (in Kentucky and Tennessee) and Tennessee (in Alabama, Tennessee, and Virginia) River systems. Historically, this species occurred in the lower Cumberland River main stem from about Caney Fork downstream to the vicinity of the Kentucky State line, and in the Tennessee River main stem from eastern Tennessee to western Tennessee. It generally has been considered a Tennessee River endemic (Simpson, 1914; Bogan and Parmalee, 1983). As a result of the failure of Wilson and Clark (1914) to collect it and the lack of other locality records, Lea's (1871) report of "Unio subglobosus" (junior synonym of Lexingtonia dolabelloides, fide Simpson, 1914) from the Cumberland River in Nashville has been discounted. However, recent finds of relict specimens (e.g., Parmalee et al., 1980; Schuster, 1988) confirm it as a historical component of the Cumberland River fauna (Starnes and Bogan, 1988; Gordon and Layzer, 1989). It is apparently extirpated from the entire Cumberland River system. Most historical records are from the Tennessee River system and indicate that it was a fairly common species found throughout the Cumberlandian region of the drainage. Records are known from two Cumberland River tributaries, Caney Fork and Red River. In addition, it is known from nearly 30 Tennessee River system tributaries, including the South Fork Powell River, Powell River, Puckell Creek, Clinch River, North Fork Holston River, Big Moccasin Creek, Middle Fork Holston River, South Fork Holston River, Holston River, French Broad River, West Prong Little Pigeon River, Tellico River, Little Tennessee River, Hiwassee River, Sequatchie River, Paint Rock River, Larkin Fork, Estill Fork, Hurricane Creek, Flint River, Limestone Creek, Elk River, Sugar Creek, Bear Creek, Duck River, North Fork Creek, Big Rock Creek, and Buffalo River. Undocumented, but now lost, populations assuredly occurred in other Cumberlandian Region tributary systems (USFWS, 2003). Populations remain in nine streams in the Tennessee River system: the Powell River, Clinch River, North Fork Holston River, Big Moccasin Creek, Middle Fork Holston River, Hiwasee River, Paint Rock River, Larkin Fork, Estill Fork, Hurricane Creek, Elk River, Bear Creek, and Duck River (USFWS, 2003; Mirarchi et al., 2004). It is also known from Lake Pontchartrain in Mississippi (Jones et al., 2005).

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

Number of Occurrences: 6 - 20
Number of Occurrences Comments: There are thought to be nine isolated populations of this species which is only abundant in two or three streams in the Tennessee River system (USFWS, 2003). Recently, it was found in the Bear Creek system in northwest Alabama (Colbert Co.) (McGregor and Garner, 2004) and the Paint Rock River system (Ahlstedt, 1996; Williams et al., 2008). Populations remain in nine streams in the Tennessee River system in Alabama, Tennessee, Kentucky, Mississippi, and Virginia: the Powell River, Clinch River, North Fork Holston River, Big Moccasin Creek, Middle Fork Holston River, Hiwasee River, Paint Rock River, Larkin Fork, Estill Fork, Hurricane Creek, Elk River, Bear Creek, and Duck River (USFWS 2003; Mirarchi et al., 2004; Parmalee and Bogan, 1998). Hubbs (2002) found relict shells in the Elk (RM 105.4), Tennessee. It is also known from Lake Pontchartrain in Mississippi (Jones et al., 2005), but this is in error (A. Bogan, pers. comm., 2009). Cicerello and Schuster (2003) indicate the Kentucky population (Upper Green River basin) is likely extirpated. It is known from the upper Clinch River, Virginia (Jones et al., 2001). Jones and Neves (2007) summarize distribution in the upper North Fork Holston River (Smyth and Bland Cos., Virginia) as rkm 136.2 to 175.3.

Population Size: 2500 - 10,000 individuals
Population Size Comments: Historically, this was a common component of Cumberland streams. According to the U.S. Fish and Wildlife Service (2003), population size data gathered during the past ten years indicates it is rare in approximately half of its extant populations. Also see Ahlstedt and Tuberville (1997).

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 Elk and Duck Rivers. Population size data gathered during the past 10 years indicates that the slabside pearlymussel is rare (experienced collectors may find 4 or fewer specimens per site of occurrence) in about half of its extant populations. Although the species is more common in other populations, it is relatively abundant in only two or three streams. Populations of the slabside pearlymussel are declining rangewide, with the possible exception of the largest populations, which may represent the only viable populations remaining (USFWS, 2003). Genetic analysis indicates the Paint Rock River population has lost most of its genetic diversity as it maintains only a single haplotype, however Ahlstedt (1998) reported it to be the most commonly encountered mussel species in a 1991 survey of the Paint Rock River system. The North Fork Holston River population similarly has low genetic diversity. The Duck River population is genetically diverse with numerous haplotypes (Grobler et al., 2006). Jones and Neves (2007) summarize distribution in the upper North Fork Holston River (Smyth and Bland Cos., Virginia) as rkm 136.2 to 175.3 where it is the third most abundant species.

Overall Threat Impact: Very high - high
Overall Threat Impact Comments: The decline of the slabside pearlymussel in the Cumberlandian Region and other mussel species in the eastern United States is primarily the result of habitat loss and degradation. Chief among the causes of decline are impoundments, stream channel alterations, water pollution, and sedimentation. The majority of the Tennessee and Cumberland River main stems and many of their largest tributaries are now impounded. The species is further impacted by channel alterations, inundation by reservoirs, siltation by agriculture and clear-cutting, chemical and organic pollution, and commercial clamming. Gravel mining activities are a threat in the Powell and Elk Rivers as well as coal mining activities in the upper Tennessee River system (USFWS, 2003). A quantitative study by Ahlstedt and Tuberville (1997) found long-term decline in mussel composition in the Powell River was attributed to general stream degradation due to coal mining activities. Completion of Columbia Dam on Duck River would destroy a significant percentage of the surviving populations. Minor threats include: overutilization for commercial, recreational, scientific, or educational purposes; disease or predation; 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, 2003).

From USFWS (2010):
Chief among the causes of decline are impoundments, stream channel alterations, water pollution, and sedimentation. Population losses due to impoundments have probably contributed more to the decline of the slabside pearlymussel and other Cumberlandian Region mussels than any other single factor. Gravel mining activities threaten the slabside pearlymussel populations in the Powell and Elk Rivers in the Tennessee River system. Acid mine runoff, thus, may be having local impacts on recruitment of the slabside pearlymussel. Coal mining activities are increasing in the upper Tennessee River system in southwest Virginia. Numerous gray-water and black-water spill events have been documented in the Powell and Clinch River drainages over the past several years. Siltation and general sedimentation runoff has been implicated in the decline of stream mussel populations. Sources of silt and sediment include poorly designed and executed timber harvesting operations and associated activities; complete clearing of riparian vegetation for agricultural, silvicultural, or other purposes; and those construction, mining, and other practices that allow exposed earth to enter streams. Although scientific collecting is not thought to represent a significant threat, localized populations could become impacted and possibly extirpated by overcollecting, particularly if this activity is unregulated. Predation on the slabside pearlymussel by muskrats represents a localized threat, as determined by Neves and Odum (1989) in the upper North Fork Holston River in Virginia.

Short-term Trend: Decline of 50-70%
Short-term Trend Comments: Populations are declining (Jenkinson, 1988; Jenkinson and Ahlstedt, 1988), sharply for only the last ten years (except possibly in Paint Rock River). It has been eliminated from at least three-fifths of the total number of streams where it was historically recorded (USFWS, 1999). Extirpations have occurred on the mainstem of the Holston River, the French Broad River, south fork Powell River, Buffalo River, the Red River, Caney Fork River (Grobler et al., 2006). This species no longer occurs in North Carolina where it was known historically from the French Broad, Little Tennessee,and Hiwassee River basin (Bogan, 2002) in Macon and Swain Cos. (LeGrand et al., 2006).

Long-term Trend: Decline of 70-90%
Long-term Trend Comments: During historical times, the slabside pearlymussel was fairly widespread and common in many Cumberlandian Region streams based on collections made in the early 1900s. However, its decline in certain streams may have begun before European colonization. The presence of the slabside pearlymussel in several streams, particularly those in the middle Tennessee River system, is known only by records from aboriginal kitchen middens. The slabside pearlymussel was considered rare by mussel experts as early as 1970. The extirpation of this species from numerous streams within its historical range indicates that substantial population losses have occurred (USFWS, 2003). It was historically in the Paint Rock (Jackson Co.) River in northern Alabama (Isom and Yokley, 1973) and the upper Elk River, Tennessee (Isom et al., 1973).

Intrinsic Vulnerability: Highly to moderately vulnerable.
Intrinsic Vulnerability Comments: The remaining populations of the slabside pearlymussel 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. Such a spill that occurred in the upper Clinch River in 1998 killed thousands of mussel specimens of several species, including three federally listed species. Furthermore, this level of isolation makes natural repopulation of any extirpated population impossible without human intervention. With the completion of numerous main stem Tennessee River dams during primarily the first half of this century, the main stem population was soon extirpated, and the remaining populations isolated. Whereas small isolated tributary populations of imperiled short-lived species (e.g., most fishes) would have theoretically died out within a decade or so after impoundment, the long-lived slabside pearlymussel would potentially take decades to expire postimpoundment (USFWS, 2003; 2010; Grobler et al., 2006).

Environmental Specificity: Moderate. Generalist or community with some key requirements scarce.
Environmental Specificity Comments: This species occurs in moderate to high gradient riffles systems in creeks to large rivers. It is generally found at depths <1 m, moderate to swift current velocities, and substrates from coarse sand to heterogenous assemblages of larger sized particles. The slabside pearlymussel is primarily a large creek to moderately-sized river species, inhabiting sand, fine gravel, and cobble substrates in relatively shallow riffles and shoals with moderate current (Parmalee and Bogan, 1998). This species requires flowing, well-oxygenated waters to thrive.

Other NatureServe Conservation Status Information

Inventory Needs: Determine the extent of existing populations, continue surveys for additional EOs, and assess potential reintroduction sites.

Protection Needs: All populations should receive protection through aquisition, easement, registry, and working with local, state, and federal government agencies on issues relating to development, water quality, river designations, etc. Management plans for conservation of environmental quality within watersheds essential. Prevention of Columbia Dam completion on Duck River critical. Land which would be inundated by flood pool is already under federal control through TVA (easements, etc.). Impetus for dam completion from a very small number of developers and land speculators. TVA apparently does not favor completion. Stretch of river (potential flood pool) under TVA control would be converted to a wildlife/mussel refuge. Several already federally-endangered mussels occur in this area. The Duck River population, with the highest genetic diversity, should be managed as a separate managment unit within the metapopulation.

Distribution
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Global Range: (1000-5000 square km (about 400-2000 square miles)) The species is restricted to the Cumberland (in Kentucky and Tennessee) and Tennessee (in Alabama, Tennessee, and Virginia) River systems. Historically, this species occurred in the lower Cumberland River main stem from about Caney Fork downstream to the vicinity of the Kentucky State line, and in the Tennessee River main stem from eastern Tennessee to western Tennessee. It generally has been considered a Tennessee River endemic (Simpson, 1914; Bogan and Parmalee, 1983). As a result of the failure of Wilson and Clark (1914) to collect it and the lack of other locality records, Lea's (1871) report of "Unio subglobosus" (junior synonym of Lexingtonia dolabelloides, fide Simpson, 1914) from the Cumberland River in Nashville has been discounted. However, recent finds of relict specimens (e.g., Parmalee et al., 1980; Schuster, 1988) confirm it as a historical component of the Cumberland River fauna (Starnes and Bogan, 1988; Gordon and Layzer, 1989). It is apparently extirpated from the entire Cumberland River system. Most historical records are from the Tennessee River system and indicate that it was a fairly common species found throughout the Cumberlandian region of the drainage. Records are known from two Cumberland River tributaries, Caney Fork and Red River. In addition, it is known from nearly 30 Tennessee River system tributaries, including the South Fork Powell River, Powell River, Puckell Creek, Clinch River, North Fork Holston River, Big Moccasin Creek, Middle Fork Holston River, South Fork Holston River, Holston River, French Broad River, West Prong Little Pigeon River, Tellico River, Little Tennessee River, Hiwassee River, Sequatchie River, Paint Rock River, Larkin Fork, Estill Fork, Hurricane Creek, Flint River, Limestone Creek, Elk River, Sugar Creek, Bear Creek, Duck River, North Fork Creek, Big Rock Creek, and Buffalo River. Undocumented, but now lost, populations assuredly occurred in other Cumberlandian Region tributary systems (USFWS, 2003). Populations remain in nine streams in the Tennessee River system: the Powell River, Clinch River, North Fork Holston River, Big Moccasin Creek, Middle Fork Holston River, Hiwasee River, Paint Rock River, Larkin Fork, Estill Fork, Hurricane Creek, Elk River, Bear Creek, and Duck River (USFWS, 2003; Mirarchi et al., 2004). It is also known from Lake Pontchartrain in Mississippi (Jones et al., 2005).

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, KYextirpated, MS, NCextirpated, TN, VA

Range Map
No map available.


U.S. Distribution by County Help
State County Name (FIPS Code)
AL Colbert (01033), Jackson (01071), Lauderdale (01077)*, Limestone (01083)*, Madison (01089), Marshall (01095)
KY Logan (21141)*
MS Tishomingo (28141)
TN Anderson (47001), Bedford (47003), Claiborne (47025), Coffee (47031), DeKalb (47041), Franklin (47051), Greene (47059)*, Hancock (47067), Hardin (47071)*, Hickman (47081), Humphreys (47085), Lawrence (47099), Lincoln (47103), Marshall (47117), Maury (47119), Moore (47127), Perry (47135)*, Polk (47139), Putnam (47141)*, Robertson (47147)*, Sequatchie (47153)*, Smith (47159)*
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 Green (05110001)*, Caney (05130108)+, Lower Cumberland-Old Hickory Lake (05130201)*, Red (05130206)+*
06 North Fork Holston (06010101)+, South Fork Holston (06010102)+, Watauga (06010103)*, Holston (06010104)*, Upper French Broad (06010105)*, Lower French Broad (06010107)*, Nolichucky (06010108)+, Watts Bar Lake (06010201)*, Lower Little Tennessee (06010204)*, Upper Clinch (06010205)+, Powell (06010206)+, Lower Clinch (06010207)+, Middle Tennessee-Chickamauga (06020001)*, Hiwassee (06020002)+, Sequatchie (06020004)+*, Guntersville Lake (06030001)+*, Wheeler Lake (06030002)+, Upper Elk (06030003)+, Lower Elk (06030004)*, Pickwick Lake (06030005)+, Bear (06030006)+, Lower Tennessee-Beech (06040001)+*, Upper Duck (06040002)+, Lower Duck (06040003)+, Buffalo (06040004)+
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
U.S. Distribution by Watershed (based on multiple information sources) Help
Ecology & Life History
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Basic Description: A freshwater mussel
General Description: Shell solid to heavy, subtriangular, compressed to inflated; anterior margin subtruncated, flatly rounded; ventral margin convex; posterior margin obliquely convex, joining ventral margin in a ventrally directed point (often blunt) at the terminus of the posterior ridge, posterio-dorsal junction often barely perceivable; beaks elevated, inclined forward, positioned in the anterior 10% of shell length, sculpted with fine irregularly wavy ridges; shell widest subcentrally, forming a broadly rounded radial ridge from the beak to the ventral margin, slope to posterior ridge flat; posterior ridge lower but distinct, subangular, convex; periostracum yellowish to brown with variously scattered narrow to wide dark green rays, rays appear broken or as blotches due to distinctly elevated termini of annual growth increments. Pseudocardinal teeth moderately large, elevated, rough, double in left valve, single in right with small denticles anterior and posterior to contiguous sulci; interdentum moderately wide, short; lateral teeth long, curved, double in left valve, single in right but may develop a smaller incomplete lamella along ventral margin of hinge plate; anterior muscle scars distinct, small, moderately deep; pallial line impressed, lighter posteriorly; posterior muscle scars distinct, impressed; beak cavity moderately developed; nacre white, may be tinged with yellow, some iridescence posteriorly.
Diagnostic Characteristics: The convexity of the posterio-dorsal outline and posterior ridge give LEXINGTONIA DOLABELLOIDES a humped appearance. Also, the otherwise subtriangular shape, forwardly inclined beaks, flattened lateral surface between the two ridges, and the wavy beak sculpture distingiush this species. Occasional small specimens superfically may resemble PLEUROBEMA OVIFORME (Conrad, 1834). Height: 49mm
Reproduction Comments: This species is a short-term, summer brooder (gravid females reported from May until August) with ectobranchous marsupia. Natural infections of glochidia have been found on popeye shiner (Notropis ariommus), Tennessee shiner (Notropis leuciodus), silver shiner (Notropis photogenis), rosyface shiner (Notropis rubellus), saffron shiner (Notropis rubricroceus), telescope shiner (Notropis telescopus) (Neves, 1991; Kitchell, 1985); as well as small mouth bass (Micropterus dolomieu) (Barnhart et al., 1995).
Ecology Comments: No ecological studies have specifically considered this species. Representative densities were estimated in several rivers by Jenkinson (1988) and Jenkinson and Ahlstedt (1988).
Habitat Type: Freshwater
Non-Migrant: N
Locally Migrant: N
Long Distance Migrant: N
Mobility and Migration Comments: This species is probably rather sessile with only limited movement through the substrate. Passive downstream movement may occur when mussels are displaced from the substrate during flooods. Major dispersal occurs while glochids are encysted on their hosts.
Riverine Habitat(s): BIG RIVER, CREEK, High gradient, MEDIUM RIVER, Moderate gradient, Riffle
Special Habitat Factors: Benthic
Habitat Comments: This species occurs in moderate to high gradient riffles systems in creeks to large rivers. It is generally found at depths <1 m, moderate to swift current velocities, and substrates from coarse sand to heterogenous assemblages of larger sized particles. The slabside pearlymussel is primarily a large creek to moderately-sized river species, inhabiting sand, fine gravel, and cobble substrates in relatively shallow riffles and shoals with moderate current (Parmalee and Bogan, 1998). This species requires flowing, well-oxygenated waters to thrive.
Adult Food Habits: Detritivore
Immature Food Habits: Parasitic
Food Comments: Larvae (glochidia) of freshwater mussels generally are parasitic on fish and display varying degrees of host specificity. No specific trophic studies have been conducted on this species. General literature claims that mussels are filter-feeders that remove phytoplankton from the water column. These assumptions are based on casual observations on mussels in situ and a few examinations of rectal contents. Baker (1928) speculated that detritus was the primary nenergy source. This has been substantiated by James (1987) and correlates well with observed microhabitat utilization. This suggests that musssels may occupy a variety of guilds such as postulated for the Sphaeriidae (see Lopez and Holopaien 1987; Gordon and Layzer 1989).
Phenology Comments: Little is known concerning the phenology of mussels other than when eggs/glochidia are held in the branchial marsupia. Being poikilothermic, activity levels would expectedly be reduced greatly during cold temperature months.
Length: 6.4 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, 2003).
Biological Research Needs: Determine habitat preferences and environmental tolerances, tolerance to various pollutants and siltation, and reproductive biology/glochidial hosts.
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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NatureServe Conservation Status Factors Edition Date: 14May2009
NatureServe Conservation Status Factors Author: Cordeiro, J. (2009); Gordon, M.E.; M. Morrison (2000)
Element Ecology & Life History Edition Date: 06Feb2007
Element Ecology & Life History Author(s): Cordeiro, J. (2007); GORDON, M. E. (1991)

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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  • Ahlstedt, S.A. 1995-1996 [1998]. Status survey for fedreally listed endangered freshwater mussel species in the Paint Rock River system, northeastern Alabama. U.S.A. Walkerana 8(19): 63-80.

  • Ahlstedt, S.A. and J.M. Tuberville. 1997. Quantitative reassessment of the freshwater mussel fauna in the Clinch and Powell rivers, Tennessee and Virginia. Pages 72-97 in K.S. Cummings, A.C. Buchanan, C.A. Mayer, and T.J. Naimo, eds. Conservation and management of freshwater mussels II: initiatives for the future. Proceedings of a UMRCC symposium, 16-18 October 1995, St. Louis, Missouri. Upper Mississippi River Conservation Committee, Rock Island, Illinois.

  • Baker, F.C. 1928b. The freshwater Mollusca of Wisconsin: Part II. Pelecypoda. Bulletin of the Wisconsin Geological and Natural History Survey, University of Wisconsin, 70(2): 1-495.

  • Barnhart, M.C., A.D. Roberts, and A.P. Farnsworth. 1995. Fish hosts of four unionids from Missouri and Kansas. Triannual Unionid Report, 7: 22.

  • Bogan, A.E. and P.W. Parmalee. 1983. Tennessee's rare wildlife. Vol. 2: The mollusks. Tennessee Wildlife Resources Agency and the Tennessee Conservation Department: Nashville, Tennessee. 123 pp.

  • Frierson, L.S. 1927. A Classified and Annotated Checklist of the North American Naiades. Baylor University Press: Waco, Texas. 111 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. and P. Yokley, Jr. 1973. The mussels of the Flint and Paint Rock River Systems of the southwest slope of the Cumberland Plateau in North Alabama-1965 and 1967. The American Midland Naturalist 89(2):442-446.

  • 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.

  • James, M.R. 1987. Ecology of the freshwater mussel Hyridella menziesi in a small oliogotrophic lake. Archives of Hydrobiology 108:337-348.

  • Jenkinson, J.J. 1988. Resurvey of freshwater mussel stocks in Duck River, TN. Report to the Tennessee Valley Authority, Knoxville, Tennessee. 20 pp.

  • Jenkinson, J.J. and S.A. Ahlstedt. 1988b. Quantitative reassessment of the freshwater mussel fauna in the Powell River, TN and VA. Tennessee Valley Authority, Knoxville, Tennessee. 28 pp.

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

  • Jones, R.L., W.T. Slack, and P.D. Hartfield. 2005. The freshwater mussels (Mollusca: Bivalvia: Unionidae) of Mississippi. Southeastern Naturalist, 4(1): 77-92.

  • Kitchel, H.E. 1985. Life history of the endangered shiny pigtoe pearly mussel, Fusconaia edgariana in the North Fork Holston River, VA. M.S. Thesis, Virginia Polytechnic Institute and State University: Blacksburg, Virginia. 124 pp.

  • LeGrand, H.E., Jr., S.P. Hall, S.E. McRae, and J.T. Finnegan. 2006. Natural Heritage Program List of the Rare Animal Species of North Carolina. North Carolina Natural Heritage Program, Raleigh, North Carolina. 104 pp.

  • Lea, I. 1871. Description of twenty new Uniones of the United States. Proceedings of the Academy of Natural Sciences of Philadelphia, 23: 189-193.

  • 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.

  • Lopez, G.R. and I.J. Holopainen. 1987. Interstitial suspension-feeding by Pisidium spp. (Pisidiiae: Bivalvia): a new guild in lentic benthos? American Malacological Bulletin, 5: 21-29.

  • McGregor, S.W. and J.T. Garner. 2004. Changes in the freshwater mussel (Bivalvia: Unionidae) fauna of the Bear Creek system of northwest Alabama and northeast Mississippi. American Malacological Bulletin, 18(1/2): 61-70.

  • 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.

  • 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.

  • Neves, R.J. 1991. Mollusks. Pages 251-320 in K. Terwilliger (ed.). Virginia's Endangered Species. Proceedings of a Symposium, Department of Game and Inland Fisheries. McDonald and Woodward Publishing Company, Blacksburg, Virginia. 672 pp.

  • Ortmann, A.E. 1914. Studies in naiades (in partim). The Nautilus, 28: 28-34.

  • Ortmann, A.E. 1917. A new type of the nayad-genus Fusconaia group of F. barnesiana, Lea. The Nautilus, 31: 58-64.

  • Ortmann, A.E. 1918a. The nayades (freshwater mussels) of the Upper Tennessee Drainage. Proceedings of the American Philosophical Society 57: 577-580.

  • Ortmann, A.E. 1918c. The nayades (freshwater mussels) of the Upper Tennessee drainage. With notes on synonymy and distribution. Proceedings of the American Philosophical Society 57: 521-626.

  • Ortmann, A.E. 1920. Correlation of shape and station in freshwater mussels. Proceedings of the American Philosophical Society, 59: 269-312.

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

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

  • Parmalee, P.W., W.E. Kippel, and A.E. Bogan. 1980. Notes on the prehistoric and present status of the naiad fauna of the middle Cumberland River, Smith County, Tennessee. The Nautilus, 94(3): 93-105.

  • Schuster, G.A. 1988. Distribution of unionids (Mollusca: Unionidae) in Kentucky. Kentucky Department of Fish and Wildlife Resources, Frankfort, Kentucky, publication 2-437-R. 1099 pp.

  • Simpson, C.T. 1914. A Descriptive Catalogue of the Naiades or Pearly Fresh-water Mussels. Bryant Walker: Detroit, Michigan. 1540 pp.

  • Starnes, L.B. and A.E. Bogan. 1988. The mussels (Mollusca: Bivalvia: Unionidae) of Tennessee. American Malacological Bulletin, 6: 19-37.

  • 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). 2003. Candidate assessment and listing priority assignment form- Lexingtonia dolabelloides. U.S. Fish and Wildlife Service, Ashville, North Carolina. 13 pp.

  • U.S. Fish and Wildlife Service (USFWS). 2010. Species assessment and listing priority assignment form: Lexingtonia dolabelloides. U.S. Fish and Wildlife Service, Endangered Species Program, Cookeville, Tennessee. 19 pp.

  • 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., 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.

  • Wilson, C.B., and H.W. Clark. 1914. The mussels of the Cumberland River and its tributaries. U.S. Bureau of Fisheries Document No. 781: 63 pp.

References for Watershed Distribution Map
  • Ahlstedt, S.A. 1995-1996. Status survey for federally listed endangered freshwater mussel species in the Paint Rock River system, northeastern Alabama, U.S.A. Walkerana 8(19):63-80.

  • 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.

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

  • Bogan, A.E. 2002. Workbook and key to the freshwater bivalves of North Carolina. North Carolina Museum of Natural Sciences: Raleigh, North Carolina. 101 pp.

  • 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.

  • Grobler, P.J., J.W. Jones, N.A. Johnson, B. Beaty, J. Struthers, R.J. Neves, and E.M. Hallerman. 2006. Patterns of genetic differentiation and conservation of the slabside pearlymussel, Lexingtonia dolabelloides (Lea, 1840) in the Tennessee River drainage. Journal of Molluscan Studies, 72: 65-75.

  • Hubbs, D. 2002. Monitoring and management of endangered mussels. 2001-02 Annual Report Project 7365, Tennessee Wildlife Resources Agency, Nashville, Tennessee. 3 pp.

  • 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.

  • McGregor, S.W., et. al. 1996. Survey of the primary tributaries of the Alabama and lower Tombigbee Rivers for listed and candidate species of mussels, snails, and crayfish: 1994-96.

  • 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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