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Home/Species/ Grand Wash Springsnail

Pyrgulopsis bacchus

Heshler, 1988

Grand Wash Springsnail

G2Imperiled Found in 2 roadless areas NatureServe Explorer →
G2ImperiledGlobal Rank
VulnerableIUCN
MediumThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.110714
Element CodeIMGASJ0150
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryInvertebrate Animal
IUCNVulnerable
Endemicendemic to a single nation
KingdomAnimalia
PhylumMollusca
ClassGastropoda
OrderLittorinimorpha
FamilyHydrobiidae
GenusPyrgulopsis
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.
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2022-09-30
Change Date2022-09-30
Edition Date2022-06-11
Edition AuthorsMiskow, E. NDNH (2022)
Threat ImpactMedium
Range Extent250-1000 square km (about 100-400 square miles)
Number of Occurrences1 - 5
Rank Reasons
This species occurs in a limited area where it is restricted to a few springs. The Arizona populations are isolated, however one of the Nevada populations may be extirpated as the spring goes dry during drought conditions and no individuals were observed the during the most recent survey effort.
Range Extent Comments
The Grand Wash springsnail is known from only 6 isolated springs in the Desert Southwest, USA. Four locations in northwestern Arizona in the Grand Canyon Parashant National Monument, Mohave County and two springs in the southeastern foothills of the Springs Mountains in Clark County, Nevada. As of 2022, the population at one of the Nevada sites may be extirpated.
Occurrences Comments
This species is known from only 6 isolated springs, of which 5 are known to have extant populations as of September 2022.
Threat Impact Comments
Prolonged drought, which causes a reduction in groundwater/spring flow, is perhaps the biggest threat to the Grand Wash springsnail. Most of the occupied sites (Grapevine, Whiskey, and Tassi) are fenced to prevent trampling from livestock and feral burros. Springs on private lands have been severely altered to the detriment of springsnails. Spring and riparian vegetation at each of these sites is very dense (i.e., overgrown), which limits the amount of open water habitat that could affect periphyton growth that the springsnails need.
Ecology & Habitat

Description

A small snail in the hydrobiid family with a shell hight between 2.3 and 3.1 mm.

Diagnostic Characteristics

Large (springsnail) 2.3-3.1 mm shell height, 4-4.25 whorls. Male and female's are the same size, the head/foot is usually dark pigmented throughout, except for tentacles and a broad patch on sides of head-foot which may be either lightly dusted or unpigmented.

Habitat

Inhabits small springs and stream outflows where it is typically found on stone, travertine, watercress, and plant debris (Hershler 1989).

Reproduction

The life cycle of most springsnails in the Pyrgulopsis genus is 9 to 15 months. Springsnails can become sexually mature within 4 months.
Other Nations (1)
United StatesN2
ProvinceRankNative
NevadaS1Yes
ArizonaS1Yes
Threat Assessments
ThreatScopeSeverityTiming
2 - Agriculture & aquaculturePervasive (71-100%)Moderate or 11-30% pop. declineHigh (continuing)
2.3 - Livestock farming & ranchingPervasive (71-100%)Moderate or 11-30% pop. declineHigh (continuing)
7 - Natural system modificationsUnknownUnknownUnknown
7.2 - Dams & water management/useUnknownUnknownUnknown
11 - Climate change & severe weatherPervasive (71-100%)Moderate or 11-30% pop. declineHigh (continuing)
11.2 - DroughtsPervasive (71-100%)Moderate or 11-30% pop. declineHigh (continuing)

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Roadless Areas (2)
Nevada (2)
AreaForestAcres
Lovell Summit SouthHumboldt-Toiyabe National Forest28,455
PotosiHumboldt-Toiyabe National Forest5,145
References (6)
  1. 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
  2. Hershler, R. and J.J. Landye. 1988. Arizona Hydrobiidae (Prosobranchia: Rissoacea). Smithsonian Contributions to Zoology, 459: 1-58.
  3. Pilgrim, K., B. Tipton, A. Ballantine, and M. Schwartz. 2020. DNA Assessment of Springsnails Collected by the US Geological Survey and Submitted by the US Fish and Wildlife Service from Northern Nevada; Inter-Agency Agreement IAA# F19PG00136
  4. 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.
  5. U.S. Fish and Wildlife Service (USFWS). 2009. Partial 90-Day Finding on a Petition to List 475 Species in the Southwestern United States as Threatened or Endangered With Critical Habitat. Proposed Rule. Federal Register 74(240): 66866-66905.
  6. U.S. Fish and Wildlife Service (USFWS). 2023. National Listing Workplan. Online. Available: https://www.fws.gov/project/national-listing-workplan