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Home/Species/ Fluted Kidneyshell

Ptychobranchus subtentus

(Say, 1825)

Fluted Kidneyshell

G2Imperiled (G2?) Found in 10 roadless areas NatureServe Explorer →
G2ImperiledGlobal Rank
Near threatenedIUCN
Very high - mediumThreat Impact
Fluted kidneyshell (Ptychobranchus subtentus). Photo by U.S. Fish & Wildlife Service, Public Domain (U.S. Government Work), via ECOS.
U.S. Fish & Wildlife Service, https://www.usa.gov/government-works
Identity
Unique IDELEMENT_GLOBAL.2.118056
Element CodeIMBIV38050
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryInvertebrate Animal
IUCNNear threatened
Endemicendemic to a single nation
KingdomAnimalia
PhylumMollusca
ClassBivalvia
OrderUnionoida
FamilyUnionidae
GenusPtychobranchus
Synonyms
Ptychobranchus subtentum(Say, 1825)
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
Lee (2008) correctly notes that in keeping with the ICZN and proper nomenclatural gender, this species should be rendered Ptychobranchus subtentus.
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2024-01-04
Change Date2024-01-04
Edition Date2024-01-04
Edition AuthorsCordeiro, J. (2009); rev. T. Cornelisse (2024)
Threat ImpactVery high - medium
Range Extent20,000-200,000 square km (about 8000-80,000 square miles)
Number of Occurrences6 - 20
Rank Reasons
This species has a limited range and due to long and short-term population declines and many ongoing threats, there are a limited number of viable occurrences.
Range Extent Comments
This species occurs in the Cumberland and Tennessee River drainages of the Ohio River Basin in Kentucky, Tennessee, and Virginia, USA (USFWS 2021a).
Occurrences Comments
This species is known from 10 populations (USFWS 2021b).
Threat Impact Comments
This species is threatened by habitat loss and degradation associated with dams and other waterway barriers, channelization, mining, 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; and drought conditions that reduce habitat, elevate water temperature, and reduce dilution of pollutants and sediment runoff (USFWS 2021a, 2021b).
Ecology & Habitat

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).

Habitat

This species inhabits shoals in small to large rivers with swift currents and sand, gravel, and cobble substrates (Gordon and Layzer 1989; USFWS 2021b).

Reproduction

Adult females of this species are long-term brooders (USFWS 2021b).
Other Nations (1)
United StatesN2
ProvinceRankNative
TennesseeS2Yes
AlabamaSXYes
KentuckyS1Yes
VirginiaS2Yes
Threat Assessments
ThreatScopeSeverityTiming
7 - Natural system modificationsLarge - restrictedSerious - moderateHigh (continuing)
7.2 - Dams & water management/useLarge - restrictedSerious - moderateHigh (continuing)
9 - PollutionLarge - restrictedSerious or 31-70% pop. declineHigh (continuing)
9.1 - Domestic & urban waste waterLarge - restrictedSerious - moderateHigh (continuing)
9.2 - Industrial & military effluentsLarge - restrictedSerious - moderateHigh (continuing)
9.3 - Agricultural & forestry effluentsLarge - restrictedSerious - moderateHigh (continuing)
11 - Climate change & severe weatherLarge (31-70%)Moderate or 11-30% pop. declineHigh (continuing)
11.1 - Habitat shifting & alterationLarge (31-70%)Moderate or 11-30% pop. declineHigh (continuing)

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Roadless Areas (10)
Idaho (1)
AreaForestAcres
Bear CreekCaribou-Targhee National Forest118,582
Tennessee (3)
AreaForestAcres
Beaver Dam CreekCherokee National Forest5,070
Little Frog Addition NECherokee National Forest321
Little Frog Addition NWCherokee National Forest628
Virginia (6)
AreaForestAcres
Bear CreekJefferson National Forest18,274
Beartown Addition AJefferson National Forest1,370
Beartown Addition BJefferson National Forest2,985
Beaver Dam CreekJefferson National Forest1,135
Garden MountainJefferson National Forest3,960
Hunting Camp Little Wolf CreekJefferson National Forest8,953
References (37)
  1. 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.
  2. 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.
  3. 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.
  4. Freshwater Mollusk Conservation Society (FMCS). 2023. The 2023 checklist of freshwater bivalves (Mollusca: Bivalvia: Unionida) of the United States and Canada. Considered and approved by the Bivalve Names Subcommittee October 2023. Online: https://molluskconservation.org/MServices_Names-Bivalves.html
  5. Global Biodiversity Information Facility (GBIF). 2024. Global Biodiversity Information Facility (GBIF) data portal. Online. Available: https://www.gbif.org/ (accessed 2024).
  6. 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.
  7. Graf, D.L. and K.S. Cummings. 2021. A 'big data' approach to global freshwater mussel diversity (Bivalvia: Unionoida), with an updated checklist of genera and species. Journal of Molluscan Studies 87(1):1-36.
  8. 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.
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  10. 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.
  11. Jones, J.W. and R.J. Neves. 2007. Freshwater mussel status: Upper North Fork Holston River, Virginia. Northeastern Naturalist, 14(3): 471-480.
  12. 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.
  13. 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.
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  15. 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.
  16. 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.
  17. MolluscaBase eds. 2024. MolluscaBase. Accessed at https://www.molluscabase.org
  18. 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.
  19. Ortmann, A.E. 1925. The naiad fauna of the Tennessee River system below Walden Gorge. The American Midland Naturalist, 9(7): 321-371.
  20. Parmalee, P.W. and A.E. Bogan. 1998. The Freshwater Mussels of Tennessee. University of Tennessee Press: Knoxville, Tennessee. 328 pp.
  21. 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.
  22. 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.
  23. Strayer, D. L. 1999. Use of flow refuges by unionid mussels in rivers. Journal of the North American Benthological Society 18(4):468-476.
  24. Strayer, D. L., and J. Ralley. 1993. Microhabitat use by an assemblage of stream-dwelling unionaceans (Bivalvia) including two rare species of <i>Alasmidonta</i>. Journal of the North American Benthological Society 12(3):247-258.
  25. 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.
  26. U.S. Fish and Wildlife Service (USFWS). 1999. Candidate and listing priority assignment forms.
  27. U.S. Fish and Wildlife Service (USFWS). 2001. Candidate and listing priority assignment form- <i>Ptychobranchus subtentum</i>. U.S. Fish and Wildlife Service, Ashville, North Carolina. 15 pp.
  28. U.S. Fish and Wildlife Service (USFWS). 2013. 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.
  29. U.S. Fish and Wildlife Service (USFWS). 2021. Fluted Kidneyshell (<i>Ptychobranchus subtentum</i>) 5-year review: summary and evaluation. U.S. Fish and Wildlife Service Atlanta Regional Office, Tennessee Ecological Services Field Office, Cookeville, Tennessee. 16 pp.
  30. U.S. Fish and Wildlife Service (USFWS). 2021. Species Status Assessment Report for the Fluted Kidneyshell (<i>Ptychobranchus subtentum</i> (=<i>subtentus</i>)), Version 1.0. February 2021. Atlanta, GA.
  31. U.S. Fish and Wildlife Service (USFWS). 2022. Recovery plan for the Fluted Kidneyshell (<i>Ptychobranchus subtentus</i>). Atlanta, Georgia. 9 pp.
  32. Van der Schalie, H. 1938. The naiad fauna of the Huron River in southeastern Michigan. Miscellaneous Publication of the Museum of Zoology, University of Michigan 40:7-78.
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  35. 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.
  36. 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.
  37. Williams, J. D., M. L. Warren, Jr., K. S. Cummings, J. L. Harris, and R. J. Neves. 1993. Conservation status of freshwater mussels of the United States and Canada. Fisheries 18(9):6-22.