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Taylorconcha serpenticola

Hershler, Frest, Johannes, Bowler, and F.G. Thompson, 1994

Bliss Rapids Snail

G1Critically Imperiled Found in 1 roadless area NatureServe Explorer →

G1Critically ImperiledGlobal Rank

VulnerableIUCN

Very high - highThreat Impact

Identity

Unique IDELEMENT_GLOBAL.2.117701

Element CodeIMGASX1020

Record TypeSPECIES

ClassificationSpecies

Classification StatusStandard

Name CategoryInvertebrate Animal

IUCNVulnerable

Endemicendemic to a single state or province

KingdomAnimalia

PhylumMollusca

ClassGastropoda

OrderLittorinimorpha

FamilyAmnicolidae

GenusTaylorconcha

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

Based on genetics and morphology, populations ot Taylorconcha from the Middle Owyhee River and lower Snake River in Idaho were found to represent a new species, Taylorconcha insperata, and not a range expansion of T. serpenticola (Hershler et al., 2006).

Conservation Status

Review Date2010-03-22

Change Date1999-09-14

Edition Date2010-03-22

Edition AuthorsCordeiro, J. (2010); Morrison, M. (1996)

Threat ImpactVery high - high

Range Extent<100-250 square km (less than about 40-100 square miles)

Number of Occurrences6 - 20

Rank Reasons

One of the few remaining Lake Idaho endemics. This species is restricted to several river stretches and springs with exceptional water quality. Decreasing water quality and competition from the the introduced New Zealand hydrobiid snail currently threaten its survival. Genetic variation was found to be uniform, however, among the three isolated occurrences (formerly united but now saprated by impoundments).

Range Extent Comments

Historically ranged discontinuously over 204 river miles in the main stem Middle Snake River and associated springs in south-central Idaho (USFWS, 1992; Hershler et al., 1994), but recently found to occupy only a short reach (about 138 river km) of the river (USFWS, 2005). It was known historically from the main stem middle Snake River and associated springs between Indian Cove Bridge (Rkm 845.6) and Twin Falls (Rkm 982.5) (Hershler et al., 1994) but remnant populations remain in Idaho, inhabiting approximately an 80 km stretch of the Snake River upstream and downstream of Hagerman, Idaho in the Thousands Springs reach of the Snake River (Richards and Arrington, 2008).

Occurrences Comments

Historically ranged discontinuously over 204 river miles in the main stem Middle Snake River and associated springs in south-central Idaho (USFWS, 1992; Hershler et al., 1994), but recently found to occupy only a short reach (about 138 river km) of the river (USFWS, 2005). Hershler et al. (2005) lists 12 sites (total < about 50 km apart) within the Middle Snake River and a few tributaries. It was known historically from the main stem middle Snake River and associated springs between Indian Cove Bridge (Rkm 845.6) and Twin Falls (Rkm 982.5) (Hershler et al., 1994) but remnant populations remain in Idaho, inhabiting approximately an 80 km stretch of the Snake River upstream and downstream of Hagerman, Idaho in the Thousands Springs reach of the Snake River (Richards and Arrington, 2008).

Threat Impact Comments

Potential threats include oxygen depletion, water pollution from agricultural runoff, irrigation, and competition from the introduced snail Potamopyrgus antipodarum (USFWS, 2005). Richards and Arrington (2008) analyzed susceptibility to desiccation during hydroelectric drawdowns and suggest that desiccation could impact populations if snails become stranded on dry substrates during rapid water-level fluctuations of the Snake River, particularly during subzero winter or extreme high summer temperatures. Despite fragmentation of the population due to dam construction, Liu and Hershler (2009) assessed genetic variation in 29 samples (820 snails) from across the range and found no evidence of reduced genetic diversity attributable to segmentation of the Snake River by dams and genetic variation among portions of drainage separated by dams was not significant.

Ecology & Habitat

Description

See Hershler et al. (1994) for complete scientific description.

Diagnostic Characteristics

Hershler et al. (1994) describe the unique features as "... the elongate radula, weakly developed anterior pedal mucous gland, and absence of female bursa copulatrix...".

Habitat

Found in springs and unpolluted, unimpounded riverine habitats on stable rocky substrates. In rivers is found in areas associated with spring influences or rapids edge environments and tends to flank shorelines (USFWS, 1992; Hershler et al., 1994). The snails do not burrow, and avoid habitats with fine sediments. The Bliss Rapids snails are moderately photophobic, residing on the lateral sides and undersides of rocks during daylight and they migrate to the uppermost surfaces of rocks at night (USFWS 2009, Stockton et al. 2012).

Ecology

Appears to have an atypically broad habitat tolerance compared to other hydrobid snails and a broad geographic range as well (Frest and Johannes, 1992). Frest and Johannes (1992) note that relatively few closely related hydrobid snails are found in any river habitats.

Reproduction

Mainstem Snake River colonies reproduce in October - February and February - March in spring colonies. Egg laying occurs within two months of reproduction and eggs appear to hatch within one month. Adults exhibit a strong seasonal die off after reproduction (USFWS, 1992).

Other Nations (1)

United StatesN1

Province	Rank	Native
Idaho	S2	Yes

Threat Assessments

Threat	Scope	Severity	Timing
7 - Natural system modifications	Large - restricted	Moderate - slight	Moderate - low
7.2 - Dams & water management/use	Large - restricted	Moderate - slight	Moderate - low
8 - Invasive & other problematic species, genes & diseases	Large - restricted	Serious - slight	High - moderate
8.1 - Invasive non-native/alien species/diseases	Large - restricted	Serious - slight	High - moderate
9 - Pollution	Large - restricted	Moderate - slight	High - moderate
9.3 - Agricultural & forestry effluents	Large - restricted	Moderate - slight	High - moderate

Roadless Areas (1)

South Dakota (1)

Area	Forest	Acres
Indian Creek	Buffalo Gap National Grassland	24,666

References (13)

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
Frest, T. J. and E. J. Johannes. 1992. Distribution and Ecology of the Endemic and Relict Mollusc Fauna of Idaho TNC's Thousand Springs Preserve. Final Report Prepared for The Nature Conservancy of Idaho.
Hershler, R. and H.-P. Liu. 2017. Annotated checklist of freshwater truncatelloidean gastropods of the western United States, with an illustrated key to the genera. Technical Note 449. U.S. Department of the Interior, Bureau of Land Management, National Operations Center, Denver, CO. 142 pp.
Hershler, R., H.-P. Liu, T.J. Frest, E.J. Johannes, and W.H. Clark. 2006. Genetic structure of the western North American aquatic gastropod genus Taylorconcha and description of a second species. Journal of Molluscan Studies, 72: 167-177.
Hershler, R., T. J. Frest, E. J. Johannes, P. A. Bowler, and F. G. Thompson. 1994. Two new genera of Hydrobiid snails (Prosobranchia: Rissooidea) from the northwestern United States. The Veliger 37(3):221-43.
Liu, H.-P. and R. Hershler. 2009. Genetic diversity and population structure of the threatened Bliss Rapids snail (Taylorconcha serpenticola). Freshwater Biology 54:1285-1299.
Lysne, S. 2009. A Guide to Southern Idaho's Freshwater Mollusks. U.S. Fish and Wildlife Service. 43 pp.
Richards, D.C. and T.D. Arrington. 2008. Threatened Bliss Rapids snail's suscptibility to desiccation: potential impacts from hydroelectric facilities. American Malacological Bulletin, 24(1/2): 91-96.
Stockton, K.A., Moffitt, C.M., Blew, D.L. and Farmer, C.N. 2012. Acute toxicity of Sodium Fluorescein to Ashy Pebblesnails Fluminicola fuscus. Northwest Science 86(3):190-197.
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.
U.S. Fish and Wildlife Service (USFWS). 1992. Endangered and Threatened Wildlife and Plants; Determination of Endangered Status or Threatened Status for Five Aquatic Snails in South Central Idaho. Final Rule. Federal Register. 57(240):59244-56.
U.S. Fish and Wildlife Service (USFWS). 1995. Snake River Aquatic Species Recovery Plan. Snake River Basin Office, Ecological Services, Boise, Idaho. 92 pp.
U.S. Fish and Wildlife Service (USFWS). 2009. Endangered and threatened wildlife and plants; 12-month finding on a petition to remove the Bliss Rapids snail (Taylorconcha serpenticola) from the list of endangered and threatened wildlife. Federal Register 74 (178):47536–47545.