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Home/Species/ Great Basin Ramshorn

Helisoma newberryi

(I. Lea, 1858)

Great Basin Ramshorn

G1Critically Imperiled Found in 3 roadless areas NatureServe Explorer →
G1Critically ImperiledGlobal Rank
Not evaluatedIUCN
HighThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.106615
Element CodeIMGASM6020
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryInvertebrate Animal
IUCNNot evaluated
Endemicendemic to a single nation
KingdomAnimalia
PhylumMollusca
ClassGastropoda
OrderBasommatophora
FamilyPlanorbidae
GenusHelisoma
Synonyms
Helisoma jacksonenseHenderson, 1932
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
Genetic examination of molecular phylogeny of global Planorboidea at the COI and 18S molecular markers indicates all North American taxa within the subfamily Planorbinae form a well-supported clade, as yet unnamed but termed C-Clade; although the genus Helisoma was not included in the assessment (Albrecht et al. 2007). There are many forms, morphs, varieties, that all intergrade (see Burch 1989, Pilsbry 1934). Burch (1989) cites three subspecies, Helisoma newberryi newberryi from Idaho, Utah, Nevada, Oregon, and California; Helisoma newberryi jacksonensis from Jackson Lake, Wyoming (from Henderson 1932), and Helisoma newberryi occidentale from Eagle Lake, Lassen Co., California (from Hanna and Henderson 1934).
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2020-12-08
Change Date2001-06-01
Edition Date2020-12-08
Edition AuthorsMiskow, E. NDNH
Threat ImpactHigh
Range Extent1000-5000 square km (about 400-2000 square miles)
Number of Occurrences1 - 5
Rank Reasons
This species has a broad range, but has become extirpated in most sites across the range due primarily to water management activities.
Range Extent Comments
This species occurs in Idaho, Wyoming, Utah, Nevada, Oregon, and California, USA, where it is generally confined to lake and large spring complexes on the periphery of the Great Basin. Burch (1989) cites three subspecies, Helisoma newberryi newberryi from Idaho, Utah, Nevada, Oregon, and California; Helisoma newberryi jacksonensis from Jackson Lake, Wyoming (from Henderson, 1932), and Helisoma newberryi occidentale from Eagle Lake, Lassen Co., California (from Hanna and Henderson, 1934). There are few remaining populations; most are in the Upper Klamath Lake and Pit River drainages, northeastern California and south central Oregon (see Frest and Johannes 1995; 1998). Taylor and Smith (1982) cite Pliocene assemblages from Honey Lake, in Lassen Co., California. Koehler (1995) lists late Pleistocene assemblages from the Dolomite site, Owens Lake, Inyo Co., California. Frest and Johannes (1995b) further list occurrences for subspecies jacksonensis as several sites in and in the immediate vicinity of Jackson Lake, Co., Wyoming, including areas in Grand Teton National Park but note no live specimens have been collected in recent years and relocation efforts were unsuccessful.
Occurrences Comments
The species has been recorded from numerous localities, but as of 2020, the best estimate is that only five or fewer occurrences still support living subpopulations (Taylor 1981, 1985; Taylor and Smith 1981; Frest and Johannes 1993, 1994, 1995a, 1995b, 1995c, 1998).
Threat Impact Comments
Springs in Upper Klamath Lake proper are badly affected by past dredging to facilitate log transport and by current severe nutrient enhancement and sedimentation. The species does not occur in areas with dense beds of macrophytes such as Myriophyhm and Elodea, nor in areas subject to eutrophication or periodic hypoxic episodes. Many springs in the Great Basin and Oregon Interior Basin are so heavily grazed as to completely extirpate or greatly reduce this species. Others are connected to irrigation canal systems; resulting sedimentation and eutrophication either eliminates or greatly reduces this species. Channeling for such systems, and for log transport long ago, has also much reduced habitat in the Upper Klamath Lake area, even when water quality remains excellent. Areas used for log transport or storage still have not regained populations of this species (Frest and Johannes, 1995b). Jackson Lake (site for H. newberryi jacksonensis) is a regulated water body; the dam at its original outflow has been modified several times (most recently in 1993) generally to increase the impoundment area.
Ecology & Habitat

Description

The Great Basin Rams-horn has a rather stout shell, diameter approximately 13 mm; whorls do not increase rapidly in width, but body whorl larger with simple aperture offset downwards at steep angle. Periphery on shoulder is sharply angular, keeled; spire not concave, but slightly convex, open umbillicus (Baker 1945).

Habitat

This is a cold water taxon most often found living just beneath the surface on oxygenated substrates habitat includes larger lakes and slow rivers, including larger spring sources and spring-fed creeks burrowing in soft mud just beneath the surface (Taylor, 1981). Helisoma newberryi are obligate or facultative detritivores, often occurring on or in oxygenated mud substrates (Frest and Johannes, 1992).

Ecology

The ecology is unusual for a planorbid. This is a cold water taxon most often found living just beneath the surface on oxygenated substrates; it is a detritivore. Many planorbid species are fairly tolerant of warm water or dissolved oxygen fluctuations or hypoxic conditions. This species appears to be very sensitive (strongly atypically so for a planorbid), and is only found in areas with saturated dissolved oxygen. Though it occurs on mud substrates, it does not tolerate extensive macrophyte beds. It was once very abundant in the Great Basin pluvial lakes.
Other Nations (1)
United StatesN1
ProvinceRankNative
OregonS1Yes
WyomingS1Yes
NevadaSXYes
CaliforniaS1Yes
IdahoSXYes
UtahSXYes
Threat Assessments
ThreatScopeSeverityTiming
2 - Agriculture & aquaculturePervasive (71-100%)Extreme or 71-100% pop. declineHigh (continuing)
7 - Natural system modificationsPervasive (71-100%)Extreme or 71-100% pop. declineHigh (continuing)

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Roadless Areas (3)
Utah (3)
AreaForestAcres
GibsonWasatch-Cache National Forest5,350
Right Hand Fork LoganWasatch-Cache National Forest15,023
Swan Creek MountainWasatch-Cache National Forest9,390
References (21)
  1. Albrecht, C., K. Kuhn, and B. Streit. 2007. A molecular phylogeny of Planorboidea (Gastropoda, Pulmonata): insights from enhanced taxon sampling. Zoologica Scripta, 36: 27-39.
  2. Burch, J.B. 1989. North American Freshwater Snails. Malacological Publications: Hamburg, Michigan. 365 pp.
  3. Chamberlin, R.V. and D.T. Jones. 1929. A descriptive catalog of the Mollusca of Utah. Bulletin of the University of Utah, [Biological Series 1(1)] 19(4): 1-203.
  4. Freshwater Mollusk Conservation Society (FMCS). 2021. The 2021 checklist of freshwater gastropods (Mollusca: Gastropods) of the United States and Canada. Considered and approved by the Gastropods Names Subcommittee December 2020. Online: https://molluskconservation.org/MServices_Names-Gastropods.html
  5. Frest, T.J., and E.J. Johannes. 1993. Mollusc Species of Special Concern within the Range of the Northern Spotted Owl. Deixis Consultants, Final Report. Unpublished report prepared for the Forest Ecosystem Management Working Group, U.S.D.A. Forest Service; Pacific Northwest Region; Portland, OR. 98 pp.
  6. Frest, T.J. and E.J. Johannes. 1994. Freshwater molluscs of the Upper Sacramento system, California, with particular reference to the Cantara Spill. 1993 yearly report to California Department of Fish & Game. Deixis Consultants: Seattle, Washington, ii + 58 pp. + app.
  7. Frest, T.J. and E.J. Johannes. 1995a. Freshwater Mollusks of the Upper Klamath Drainage, Oregon. Final report to the Oregon Natural Heritage Program, 821 SE 14th, Portland, Oregon 97214. Contract #ORFO 092094. 68 pp. plus appendices.
  8. Frest, T.J. and E.J. Johannes. 1995b. Freshwater Mollusks of the Upper Sacramento System, California, with Particular Reference to the Cantara Spill. 1995 final report to California Department of Fish and Game. Deixis Consultants, Seattle, Washington. 88 pp. + appendices.
  9. Frest, T.J. and E.J. Johannes. 1995c. Interior Columbia Basin mollusk species of special concern. Final Report (contract #43-0E00-4-9112) prepared for Interior Columbia Basin Ecosystem Management Project. Deixis Consultants, Seattle, Washington. 274 pp. + tabs., figs.
  10. Frest, T.J. and E.J. Johannes. 1998. Freshwater Mollusks of the Upper Klamath Drainage, Oregon. 1998 yearly report to Oregon Natural Heritage Program and Klamath Project, USDI Bureau of Reclamation. Deixis Consultants, Seattle, Washington. 200 pp. + appendices.
  11. Hanna, G.D. and J. Henderson. 1934. A review of the genus <i>Carinifex </i>Binney. Reports of the American Malacological Union 1934(3): 6.
  12. Henderson, J. 1932. <i>Carinifex jacksonensis</i>, new species, from Wyoming. The Nautilus 45:133-134.
  13. Koehler, P.A. 1995. Late Pleistocene mollusks from the Dolomite site, Owens Lake Playa, California. The Valiger 38(4):312-318.
  14. Oliver, G.V. and W.R. Bosworth, III. 1999. Rare, imperiled, and recently extinct or extirpated mollusks of Utah. Report ot the Utah Division of Wildlife Resources, Publication Number 99-29, Salt Lake City, Utah. 231 pp.
  15. Pilsbry, H.A. 1934. Review of the Planorbidae of Florida, with notes on other members of the family. Proceedings of the Academy of Natural Sciences of Philadelphia, 86: 29-66.
  16. Taylor, D.W. 1981b. Freshwater mollusks of California: a distributional checklist. California Fish and Game 67(3):140-163.
  17. Taylor, D.W. 1985. Evolution of freshwater drainages and molluscs in western North America. Pages 265-321 in C.J. Smiley (ed.) Late Cenozoic History of the Pacific Northwest. Pacific Division AAAS and California Academy of Science: San Francisco, California. 417 pp.
  18. Taylor, D.W. and G.R. Smith. 1981 [1982]. Pliocene molluscs and fishes from northeastern California and northwestern Nevada. Contributions from the Museum of Paleontology, The University of Michigan 25(18):339-413.
  19. Tronstad, L.M. and M. D. Andersen. 2018. Aquatic snails of the Snake and Green River Basins of Wyoming. Report prepared by the Wyoming Natural Diversity Database for the Wyoming Fish and Wildlife Department. 44 pp.
  20. 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.
  21. U.S. Fish and Wildlife Service (USFWS). 2025. 90-Day Findings for Nine Species. Notification of petition findings and initiation of status reviews. Federal Register 90(162): 41359.