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Fusconaia subrotunda

(I. Lea, 1831)

Longsolid

G3Vulnerable Found in 15 roadless areas NatureServe Explorer →
G3VulnerableGlobal Rank
VulnerableIUCN
HighThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.118395
Element CodeIMBIV17120
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryInvertebrate Animal
IUCNVulnerable
Endemicendemic to a single nation
KingdomAnimalia
PhylumMollusca
ClassBivalvia
OrderUnionoida
FamilyUnionidae
GenusFusconaia
Synonyms
Fusconaia maculata(Rafinesque, 1820)
Other Common Names
Long Solid Mussel (EN) Longsolid Naiad (EN)
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.
Taxonomic Comments
The members of the genus Fusconaia are among the most difficult to identify in North America. Arguments arise even among taxonomists regarding the "species" represented in the genus. Stansbery (1983) summarized many of the problems and identified a few of the shell characters used to separate Fusconaia subrotunda from the morphologically similar and often co-occurring Fusconaia flava and the "forms" Fusconaia trigona (Lea, 1831), Fusconaia undata (Barnes, 1823), and Fusconaia wagneri (Baker, 1928). A few "morphs" have been variously identified and named but no rigorous genetic, anatomic, or conchological study has ever been published on this group to help elucidate species boundaries or relationships.

Synonyms include: Unio politus Say, 1834; Unio kirtlandianus Lea, 1834; Unio leseurianus Lea, 1840; Unio pilaris Lea, 1840; Unio globatus Lea, 1871; Unio bursa-pastoris B.H. Wright, 1896; Quadrula flexuosa Simpson, 1900; Quadrula andrewsii Marsh, 1902; and Quadrula beauchampii Marsh, 1902.

Some authors (i.e. Watters, 1995) use Fusconaia maculata Rafinesque, 1820 for this species. In an unpublished study of molecular systematics, Campbell and Harris (2006) found this species placed confidently within the genus Fusconaia.
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2023-12-14
Change Date1998-03-17
Edition Date2023-12-14
Edition AuthorsCummings, K.S. (1998); Cordeiro, J. (2009); T. Cornelisse (2023)
Threat ImpactHigh
Range Extent200,000-2,500,000 square km (about 80,000-1,000,000 square miles)
Number of Occurrences21 - 80
Rank Reasons
This species has a moderately large range but due to long and short-term population declines and many ongoing threats, there are a decreasing number of viable occurrences.
Range Extent Comments
This species occurs in the Ohio, Cumberland, and Tennessee River basins in the United States, in New York, Pennsylvania, Ohio, West Virginia, Virginia, North Carolina, Kentucky, Tennessee, and Alabama (USFWS 2022).
Occurrences Comments
This species is known from 60 populations (USFWS 2022; USFWS 2023).
Threat Impact Comments
This species is threatened by habitat loss and degradation associated with dams and other waterway barriers, channelization, mining, and dredging operations; specifically, pollutants in wastewater discharges, including from sewage treatment plants and industrial operations; runoff of silt, fertilizers, pesticides, and other pollutants from land disturbance activities, such as development and agriculture implemented without adequate measures to control runoff, invasive species, and drought conditions that reduce habitat, elevate water temperature, and reduce dilution of pollutants and sediment runoff (USFWS 2022).
Ecology & Habitat

Description

Shell relatively large, solid, elongate, oval or elliptical, and moderately inflated. Anterior end rounded, posterior end rounded or bluntly pointed. Dorsal margin and ventral margins straight to slightly curved. Umbos low and directed forward. Shell smooth, light brown, becoming dark brown to black in adults. Green rays present on juveniles and the umbos of older shells.

Pseudocardinal teeth large and well developed; two in the left valve, one in the right (occasionally with a small tooth on either side). Lateral teeth large and straight; two in the left valve, one in the right. Beak cavity very deep. Nacre white, iridescent posteriorly (Cumings and Mayer, 1992).

Habitat

This species is found in streams to medium rivers with sand or gravel substrates and low flows; the species likely has a tolerance for pool habitats (Cicerello and Schuster 2003; USFWS 2022).
Other Nations (1)
United StatesN3
ProvinceRankNative
IllinoisSXYes
TennesseeS3Yes
AlabamaS1Yes
New YorkS1Yes
GeorgiaSXYes
PennsylvaniaS2Yes
VirginiaS3Yes
IndianaSXYes
OhioS1Yes
North CarolinaS1Yes
West VirginiaS3Yes
KentuckyS3Yes
Threat Assessments
ThreatScopeSeverityTiming
3 - Energy production & miningRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
3.2 - Mining & quarryingRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
7 - Natural system modificationsLarge - restrictedModerate or 11-30% pop. declineHigh (continuing)
7.2 - Dams & water management/useLarge - restrictedModerate or 11-30% pop. declineHigh (continuing)
8 - Invasive & other problematic species, genes & diseasesRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
8.1 - Invasive non-native/alien species/diseasesRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
8.1.2 - Named speciesRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
9 - PollutionLarge (31-70%)Serious - moderateHigh (continuing)
9.1 - Domestic & urban waste waterRestricted (11-30%)Serious - moderateHigh (continuing)
9.1.2 - Run-offRestricted (11-30%)Serious - moderateHigh (continuing)
9.2 - Industrial & military effluentsLarge - restrictedSerious - moderateHigh (continuing)
9.3 - Agricultural & forestry effluentsRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
11 - Climate change & severe weatherRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
11.1 - Habitat shifting & alterationRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)

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Roadless Areas (15)
Idaho (1)
AreaForestAcres
Bear CreekCaribou-Targhee National Forest118,582
Illinois (1)
AreaForestAcres
Burke BranchShawnee National Forest6,231
Indiana (1)
AreaForestAcres
Mogan RidgeHoosier National Forest8,435
North Carolina (5)
AreaForestAcres
Bald MountainPisgah National Forest11,085
Boteler PeakNantahala National Forest4,205
Graveyard Ridge (addition)Pisgah National Forest1,958
South Mills RiverPisgah National Forest8,588
Tusquitee BaldNantahala National Forest13,670
Pennsylvania (3)
AreaForestAcres
Allegheny FrontAllegheny National Forest7,430
Hearts ContentAllegheny National Forest221
Verbeck IslandAllegheny National Forest14
Tennessee (4)
AreaForestAcres
Bald MountainCherokee National Forest11,743
Little Frog Addition NECherokee National Forest321
Little Frog Addition NWCherokee National Forest628
Upper Bald RiverCherokee National Forest9,202
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