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Plethobasus cooperianus

(I. Lea, 1834)

Orangefoot Pimpleback

G1Critically Imperiled Found in 2 roadless areas NatureServe Explorer →
G1Critically ImperiledGlobal Rank
Critically endangeredIUCN
Very high - highThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.120557
Element CodeIMBIV34020
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryInvertebrate Animal
IUCNCritically endangered
CITESAppendix I
Endemicendemic to a single nation
KingdomAnimalia
PhylumMollusca
ClassBivalvia
OrderUnionoida
FamilyUnionidae
GenusPlethobasus
Synonyms
Obovaria striataRafinesque, 1820Plethobasus striatus(Rafinesque, 1820)
Other Common Names
Orange-footed Pimpleback Mussel (EN) Orangefoot pimpleback (pearlymussel) (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
This species was originally described with the specific epithet cooperianus by Lea in 1834. Bogan and Parmalee (1983) considered Obovaria striata Rafinesque, 1820, to be the same species and gave priority to Rafinesque's name. Most authors and Turgeon et al. (1998) use the epithet cooperianus.
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2024-01-05
Change Date1998-03-17
Edition Date2024-01-05
Edition AuthorsCummings, K. S. (1998); rev. J. Cordeiro (2009); rev. T. Cornelisse (2024)
Threat ImpactVery high - high
Range Extent5000-20,000 square km (about 2000-8000 square miles)
Number of Occurrences1 - 5
Rank Reasons
This species has a moderate range but due to long-term population declines and many ongoing threats, there are few viable occurrences.
Range Extent Comments
This species occurs in the United States in the Tennessee River in Tennessee and Kentucky and in the Ohio River in Kentucky and Illinois (USFWS 2018).
Occurrences Comments
This species is known from three extant occurrences (USFWS 2023).
Threat Impact Comments
This species is threatened by habitat loss, degradation, and fragmentation due to dams and other waterway barriers, development, and dredging operations; 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 (USFWS 2018, 2023).
Ecology & Habitat

Description

SHELL EXTERIOR: Shell thick, solid, round or slightly elongate, and moderately inflated to compressed. Anterior end rounded, posterior end rounded to bluntly pointed. Dorsal margin straight or slightly curved, ventral margin curved. Umbos low, directed forward and only slightly elevated above the hinge line. Anterior fourth of the shell smooth, numerous pustules present on the posterior three-fourths. Periostracum rayless, light brown in small shells, becoming chestnut or dark brown color in larger individuals. Length to four inches.

SHELL INTERIOR: Pseudocardinal teeth well developed; two in the right valve, one in the right, with a smaller tooth on either side. Lateral teeth rather short, straight or slightly curved; two in the left valve, one in the right Beak cavity very deep. Nacre white, usually with pink or salmon near the beak cavity, iridescent posteriorly (Cummings and Mayer, 1992).

Habitat

This species is found in medium to large rivers with moderate gradients in sand, gravel, and cobble substrates in riffles and shoals (Gordon and Layzer 1989; Bogan and Parmalee 1983; Cummings and Mayer 1992; USFWS 1984).
Other Nations (1)
United StatesN1
ProvinceRankNative
IndianaSXYes
TennesseeS1Yes
OhioSXYes
IllinoisS1Yes
West VirginiaSXYes
AlabamaSXYes
IowaSNRYes
PennsylvaniaSHYes
KentuckyS1Yes
Threat Assessments
ThreatScopeSeverityTiming
1 - Residential & commercial developmentRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
1.1 - Housing & urban areasRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
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 (31-70%)Serious or 31-70% pop. decline—
7.2 - Dams & water management/useLarge (31-70%)Serious or 31-70% pop. decline—
9 - PollutionLarge (31-70%)Serious - moderateHigh (continuing)
9.2 - Industrial & military effluentsLarge - restrictedModerate or 11-30% pop. declineHigh (continuing)
9.3 - Agricultural & forestry effluentsLarge - restrictedModerate or 11-30% pop. declineHigh (continuing)

—

Roadless Areas (2)
Idaho (1)
AreaForestAcres
Bear CreekCaribou-Targhee National Forest118,582
Illinois (1)
AreaForestAcres
Burke BranchShawnee National Forest6,231
References (57)
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