Roadless Areas
Home/Species/ Coosa Moccasinshell

Medionidus parvulus

(I. Lea, 1860)

Coosa Moccasinshell

G1Critically Imperiled (G1?) Found in 5 roadless areas NatureServe Explorer →
G1Critically ImperiledGlobal Rank
EndangeredIUCN
Very high - highThreat Impact
Coosa moccasinshell (Medionidus parvulus). 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.2.113013
Element CodeIMBIV28040
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryInvertebrate Animal
IUCNEndangered
Endemicendemic to a single nation
KingdomAnimalia
PhylumMollusca
ClassBivalvia
OrderUnionoida
FamilyUnionidae
GenusMedionidus
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
In older literature (e.g. Johnson 1977) M. parvulus was synonymized with M. acutissimus.
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2023-12-29
Change Date2023-12-29
Edition Date2023-12-29
Edition AuthorsCordeiro, J. (2011); rev. Cornelisse, T. (2023)
Threat ImpactVery high - high
Range Extent1000-20,000 square km (about 400-8000 square miles)
Number of Occurrences1 - 20
Rank Reasons
This species has a limited range and due to long and short-term population declines and many ongoing threats, it has few viable occurrences.
Range Extent Comments
This species occurs in the United States in the Conasauga River and Holly Creek in Tennessee and Georgia and has been reintroduced into Alabama (USFWS 2019; GBIF 2023).
Occurrences Comments
This species is known from five occurrences, three in the Conasauga River and two in Holly Creek, as well as one from a reintroduction effort in Alabama (USFWS 2019; GBIF 2023).
Threat Impact Comments
This species is threatened by sedimentation, nutrient, and chemical pollution from land conversion activities, including agriculture, oil and gas operations, and coal mining, dams and water diversions that change hydrological conditions, host fish distribution, and prevent habitat connectivity and recolonization, and habitat alteration due to climate change, including increased water temperatures and drought (USFWS 2008, 2019).
Ecology & Habitat

Description

This is a small species with a thin, fragilke, and elongate shell that is elliptical to rhomboidal in outline. The posterior ridge is inflated and smoothly rounded, terminating in a broadly rounded point. The posterior slope is finely corrugated. Periostracum is yellow-brown to dark brown and has fine green rays. Nacre is blue, occasionally with salmon-colored spots (FWS, 2003).

Diagnostic Characteristics

Medionidus parvulus can be distinguished from the similar Medionidus acutissimus by its size, broadly rounded posterior ridge and apex, and nacre color (U. S. Fish and Wildlife Service, 1993)

Habitat

The species is found in sand and gravel in highly oxygenated, clear streams and small rivers with moderate to strong flows (USFWS 2000, 2019).

Reproduction

Gravid females likely migrate to the surface of the stream bottom during spring glochidial release periods and remain buried completely the rest of the year (USFWS 2003, 2019).
Other Nations (1)
United StatesN1
ProvinceRankNative
AlabamaSXYes
GeorgiaS1Yes
TennesseeS1Yes
Threat Assessments
ThreatScopeSeverityTiming
3 - Energy production & miningRestricted (11-30%)Serious - moderateHigh (continuing)
3.2 - Mining & quarryingRestricted (11-30%)Serious - moderateHigh (continuing)
7 - Natural system modificationsLarge (31-70%)Serious or 31-70% pop. declineHigh (continuing)
7.2 - Dams & water management/useLarge (31-70%)Serious or 31-70% pop. declineHigh (continuing)
9 - PollutionLarge - restrictedSerious - moderateHigh (continuing)
9.3 - Agricultural & forestry effluentsLarge - restrictedSerious - moderateHigh (continuing)
9.3.2 - Soil erosion, sedimentationLarge - restrictedSerious - moderateHigh (continuing)
11 - Climate change & severe weatherLarge - restrictedModerate or 11-30% pop. declineHigh (continuing)
11.1 - Habitat shifting & alterationLarge - restrictedModerate or 11-30% pop. declineHigh (continuing)

—

Roadless Areas (5)
Alabama (2)
AreaForestAcres
Cheaha ATalladega National Forest236
Oakey MountainTalladega National Forest6,129
Georgia (3)
AreaForestAcres
Foster BranchChattahoochee National Forest171
Ken MountainChattahoochee National Forest527
Pink KnobChattahoochee National Forest12,127
References (37)
  1. Biological Resources Division, USGS. 1997. Database of museum records of aquatic species. Compiled by J. Williams (USGS-BRD, Gainesville, FL).
  2. Bogan, Art (Curator of Aquatic Invertebrates, North Carolina State Museum of Natural Sciences). 1997. Review and annotation of mussel watershed distribution maps for TN. Review requested by Ruth Mathews, TNC. September 1997.
  3. 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
  4. Global Biodiversity Information Facility (GBIF). 2023. Global Biodiversity Information Facility (GBIF) data portal. Online. Available: https://www.gbif.org/ (accessed 2023).
  5. 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.
  6. Haag, W. R. 2019. Reassessing enigmatic mussel declines in the United States. Freshwater Mollusk Biology and Conservation 22(2):43-60.
  7. Howard, A. D. 1915. Some exceptional cases of breeding among the Unionidae. The Nautilus 29:4-11.
  8. Johnson, P.D., C. St. Aubin, and S.A. Ahlstedt. 2005. Freshwater mussel survey results for the Cherokee and Chattahoochee districts of the United States Forest Service in Tennessee and Georgia. Report to the U.S. Fish and Wildlife Service, Daphne, Alabama. 32 pp.
  9. Johnson, R.I. 1977. Monograph of the genus <i>Medionidus </i>(Bivalvia: Unionidae) mostly from the Apalachicolan region, southeastern United States. Occasional Papers on Mollusks, 4(56): 161-187.
  10. Lefevre, G. and W. T. Curtis. 1912. Studies on the reproduction and artificial propagation of fresh-water mussels. Bulletin of the Bureau of Fisheries 30:102-201.
  11. Major, Smoot (Tennessee Division of Natural Heritage). 1997. Review and annotation of fish and mussel watershed distribution maps. Review requested by Ruth Mathews, TNC on 19 August 1997.
  12. McGregor, S.W., P.E. O'Neil, and J.M. Pierson. 2000. Status of the freshwater mussel (Bivalvia: Unionidae) fauna of the Cahaba River system, Alabama. Walkerana, 11(26): 215-237.
  13. 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.
  14. MolluscaBase eds. 2024. MolluscaBase. Accessed at https://www.molluscabase.org
  15. 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.
  16. Ortmann, A.E. 1924. The naiad fauna of Duck River in Tennessee. The American Midland Naturalist, 9: 18-62.
  17. Parmalee, P.W. and A.E. Bogan. 1998. The Freshwater Mussels of Tennessee. University of Tennessee Press: Knoxville, Tennessee. 328 pp.
  18. Simpson, C.T. 1914. A Descriptive Catalogue of the Naiades or Pearly Fresh-water Mussels. Bryant Walker: Detroit, Michigan. 1540 pp.
  19. 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.
  20. Strayer, D. L. 1999. Use of flow refuges by unionid mussels in rivers. Journal of the North American Benthological Society 18(4):468-476.
  21. 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.
  22. 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.
  23. United States Fish and Wildlife Service (USFWS). 2019. Coosa moccasinshell Recovery Plan Amendment. Atlanta, Georgia. 11 pp.
  24. U.S. Fish and Wildlife Service (USFWS). 1989e. Endangered and threatened wildlife and plants; designation of the cracking pearly-mussel as an Endangered species. Federal Register, 54(187): 39850-39853.
  25. U.S. Fish and Wildlife Service (USFWS). 1997. Draft Recovery Plan for the Mobile River basin aquatic ecosystem. U.S. Fish and Wildlife Service, Southeast Region, Atlanta, Georgia.
  26. U.S. Fish and Wildlife Service (USFWS). 2000. Recovery plan for the Mobile River basin aquatic ecosystem. U.S. Fish and Wildlife Service, Southeast Region, Atlanta, Georgia. 128 pp.
  27. U.S. Fish and Wildlife Service (USFWS). 2003. Endangered and Threatened Widlife and plants; proposed designation of critical habitat for three threatened mussels and eight endangered mussels in the Mobile River basin; proposed rule. Federal Register, 68(58): 14752-14832.
  28. U.S. Fish and Wildlife Service (USFWS). 2004. Endangered and Threatened Widlife and plants; designation of critical habitat for three threatened mussels and eight endangered mussels in the Mobile River basin; final rule. Federal Register, 69(126): 40083-40171.
  29. U.S. Fish and Wildlife Service (USFWS). 2019a. Finelined Pocketbook (<i>Hamiota</i> (=<i>Lampsilis</i>) <i>altilis</i>), Orangenacre Mucket (<i>Hamiota</i> (=<i>Lampsilis</i>) <i>perovalis</i>), Alabama Moccasinshell (<i>Medionidus acutissimus</i>), Coosa Moccasinshell (<i>Medionidus parvulus</i>), Southern Clubshell (<i>Pleurobema decisum</i>), Dark Pigtoe (<i>Pleurobema furvum</i>), Southern Pigtoe (<i>Pleurobema georgianum</i>), Ovate Clubshell (<i>Pleurobema perovatum</i>, Triangulua Clubshell (<i>Pleurobema greenii</i>), 5-year review: summary and evaluation. U.S. Fish and Wildlife Service, South Atlantic-Gulf Region (Region 2), Alabama Ecological Services Field Office, Daphne, Alabama. 69 pp.
  30. U.S. Fish and Wildlife Service (USFWS). 2023. Initiation of 5-Year Status Reviews for 67 Southeastern Species. Notice of initiation of reviews; <br/>request for information. Federal Register 88(91): 30324-30328.
  31. 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.
  32. Vaughn, C.C. 2018. Ecosystem services provided by freshwater mussels. Hydrobiologia, 810: 15-27.
  33. Watters, G. T. 1992. Unionids, fishes, and the species-area curve. Journal of Biogeography 19:481-490.
  34. 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.
  35. 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.
  36. Williams, J.D. and M.H. Hughes. 1998. Freshwater mussels of selected reaches of the main channel rivers in the Coosa drainage of Georgia. U.S. Geological report to U.S. Army Corps of Engineers, Mobile District, Alabama. 21 pp.
  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.