SPECIES FACT SHEET
Scientific Name: Lanx klamathensis Hannibal 1912
Common Name: scale lanx
Phylum: Mollusca
Class: Gastropoda
Order: Basommatophora
Family: Lymnaeidae
Conservation Status:
Global Status: G1 (June 2000)
National Status: United States (N1) (June 2000)
State Statuses: Oregon (S1), California (S1)
(NatureServe 2015)
IUCN Red List: NE – Not evaluated
Technical Description:
The scale lanx was previously described as belonging to the family Ancylidae
due to its limpet-like shell (ancylid species have shells that resemble low flat
cones); however, subsequent authors have placed it in the family Lymnaeidae
and genus Lanx (Baker 1925; Pilsbry 1925; Turgeon et al. 1998). This species
has also previously been described as a member of the subgenus Walkerola
(Hannibal 1912; Burch 1989). Others (Taylor 1981; Frest and Johannes 1995)
do not recognize the subgenus, and also indicate that shell height to width
ratio should be considered a species- not genus-level character.
The scale lanx is an aquatic pulmonate snail in the family Lymnaeidae. It has a
complete circumferential muscle scar, easily distinguishing species in this
family from other freshwater limpets (Burch 1989). This species has a large
shell (11-16mm length, 7.5-9.5mm width, and 3-3.5mm height, Hannibal
1912; Henderson 1936). It is recognizable by its characteristic flattened, thin
shell whose width and length is many times greater than height (Hannibal
1912; Pilsbry 1925; Henderson 1936; Frest and Johannes 1995).
Life History:
The scale lanx is a freshwater snail lacking gills, ctenidia, and lung-like
structures, breathing instead through a vascularized mantle (Pilsbry 1925;
Frest and Johannes 2005). Although the specific mode of breeding and
reproduction is unstudied in this species, basommatophoran snails generally
reproduce sexually, and lymnaeids in particular are hermaphroditic. They
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generally lay long, sausage-shaped egg masses, likely in the spring. Eggs are
attached to plants and rocks (Brown 2001; Smith 2001). The life span of this
species in unknown; however, a typical life span of snails in the lymnaeid
family is between 9 and 15 months, though some lymnaeids may live as long as
2 to 4 years (Smith 2001). Frest and Johannes (2005) report that lancids,
unlike other lymnaeids, reproduce just once during a one-year life cycle. They
also report small egg capsules containing fewer than 12 eggs.
Lymnaeids are considered “microherbivores,” whose diet consists of algae and
diatoms scraped from rocks and macrophytes (Brown 2001). Many aspects of
this species’ life history are not well understood.
Range, Distribution, and Abundance:
Range: The five members of this genus, the rotund lanx (Lanx subrotunda
Tryon 1865); highcap lanx (Lanx alta Tryon 1865); scale lanx (Lanx
klamathensis Hannibal 1912); kneecap lanx (Lanx patelloides Lea 1856); and
Banbury Springs limpet (Lanx sp. 1), are restricted to western states
(NatureServe 2015).
This species has been reported in the Klamath Basin of Oregon and California;
however, there appears to be some evidence that this species is now extirpated
from California and may be limited to approximately 10 sites in Oregon
(NatureServe 2015). It has been reported at multiple locations in Upper
Klamath Lake, the Klamath River, the Link River, and numerous springs.
Distribution: One museum record from Washington (CAS:IZ:121580; no locality
information) should be considered suspect, as this is beyond the known range.
In Oregon, Hannibal (1912) and Henderson (1936) reported early records at
Upper Klamath Lake, the type locality for this species (south end), including
“Government Irrigation Dam” and “Algoma, on the east shore” (Henderson
1936); most observations of this species have been in the vicinity of Upper
Klamath Lake, in various localities. Other records include the Link River
(Hannibal 1912; ANSP 113843; Frest and Johannes 1998) and “slow tributary
streams” of the lake (Taylor 1981). Hannibal (1912) also reported this species
in the Klamath River at Keno, and more recent records (1997; 2006) also
document this species in the Klamath River in Oregon at Big Bend and near
Rock Creek.
This species has been observed at a number of spring sites, including Barkley
Spring (USNM 892426; USNM 1152131; Frest and Johannes 1998); Harriman
Spring (CAS:IZ:79012; Frest and Johannes 1998); Odessa Spring, Malone
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Spring, and Tecumseh Spring (Frest and Johannes 1998; OR/WA BLM 2015).
A record at Ouxly Spring (OSU OSAC: KLF06-025b) was reported by N. Duncan
as Lanx sp. This record has been included as a possible record for Lanx
klamathensis, given the habitat and location.
BLM/Forest Service Land: This species is documented on the Lakeview District
BLM in the Klamath Falls Resource Area and is suspected on the Upper
Klamath River ACEC. This species is also documented on the Fremont-Winema
National Forest. This species is suspected on the Rogue-Siskiyou National
Forest and on the Medford District BLM based on a published account by Frest
and Johannes (1998).
Abundance: Henderson (1936) noted the species “in abundance” on the east
shore of Upper Klamath Lake. Frest and Johannes (1998) report the species as
rare at one site and common at another.
Habitat Associations:
Habitat includes spring-fed lakes, as well as larger tributary streams that may
be slow-moving and spring-fed, and large limnocrene springs or spring
complexes (Taylor 1981; Frest and Johannes 2000; NatureServe 2015). It is
found on cobble and boulders in areas with flowing, oxygenated water of high
quality (Frest and Johannes 1993).
Populations in lakes are limited to the vicinity of perennial spring input. The
species, like all lancids, is an obligate perilithon grazer and lithophile, and
occurs on cobbles and boulders, generally in areas with current and always at
sites with oxygenated, high-quality clear water. The species is not found in
areas with sediment or silt deposits, or in areas subject to low oxygen levels
(Frest and Johannes 1995).
Threats:
Extensive human modification to rather specialized habitat is an ongoing
threat to the scale lanx. Impacts include conversion of habitat for irrigation,
water impoundments, spring diversions and developments, and water
abstraction. For example, populations once found in Agency Lake appear to be
extirpated, following drying in the area in the early 1990s (Frest and Johannes
1995; NatureServe 2015). Nonindigenous species are also linked to gastropod
imperilment (Johnson et al. 2013), and several nonindigenous mollusks are
present in the Klamath Basin (USGS 2015).
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Poor water quality, such as that associated with hypereutrophic Upper
Klamath Lake, and habitat disturbance like grazing also limit occurrence of
this species, which is particularly sensitive to low concentrations of or high
fluctuations in dissolved oxygen. Many large springs and spring-fed pools are
grazed; those peripheral to Klamath Lake have been modified. Even in the best
remaining spring pools and spring-fed creeks, the scale lanx seems to be
confined to limited areas with the best water quality (Frest and Johannes 1995;
NatureServe 2015). This species was recommended by Frest and Johannes
(1993; 1995) for federal listing as “endangered.”
Conservation Considerations:
Inventory: Significant range extensions or the identification of large numbers of
additional sites are considered very unlikely by Frest and Johannes (1995). As
most records of this species date from the 1990s, surveys at known sites will
provide valuable information about the current status, range, and population
characteristics of this species. Comparing records of nonindigenous aquatic
species to known L. klamathensis sites will also provide valuable information
for conservation and management.
Management: In areas managed for multiple purposes, avoid or minimize
conversion of habitat, whether directly or indirectly through impacts to water
quality (temperature, dissolved oxygen, turbidity) or water quantity (water level
fluctuation, draining, diversion). Activities that result in siltation,
sedimentation, or reduced flow may also impact this species’ habitat. Nonpoint
source pollution, including urban or agricultural runoff and pesticides, may
also reduce water quality. Limit these impacts where possible and monitor
their effects. If insecticide or herbicide use is planned for areas where this
species occurs, assess alternatives to their use.
Version 2:
Prepared by: Emilie Blevins
Xerces Society for Invertebrate Conservation
Date: March 2015
Edited by: Sarina Jepsen
Xerces Society for Invertebrate Conservation
Date: March 2015
Version 1:
Prepared by: Theresa Stone
Umpqua National Forest
September 2009
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Edited by: Rob Huff
FS/BLM Conservation Planning Coordinator
January 2010
ATTACHMENT 1:
ATTACHMENT 2:
ATTACHMENT 3:
ATTACHMENT 4:
ATTACHMENT 5:
for this species
ATTACHMENT 1:
References
List of pertinent or knowledgeable contacts
Map of species’ occurrence
Photographs of this species
Aquatic Gastropod Survey Protocol, including specifics
References
Baker, H. B. 1925. Anatomy of Lanx, a limpet-like Lymnaeid mollusk.
Proceedings of the California Academy of Sciences, 4th Series 14(8): 143-169.
Brown, K. M. 2001. Mollusca: Gastropoda, in Thorp, J.H., and Covich, A.P.,
eds., Ecology and classification of North American freshwater invertebrates, 2nd
edition: San Diego, Academic Press, p. 297-329.
Burch, J. B. 1989. North American Freshwater Snails. Malacological
Publications, Hamburg, MI. 365 pp.
Dillon, R. T. 2006. The Xerces Society Pacific Northwest Taxonomic Workshop.
Missoula, Montana May 11-12, 2006 - Gastropoda.
Frest, T. J. and E. J. Johannes. 1993. Mollusk Species of Special Concern
Within the Range of the Northern Spotted Owl. Final Report to Forest
Ecosystem Management Working Group, USDA Forest Service. Deixis
Consultants, Seattle, Washington. 98 pp.
Frest, T. J. and E. J. Johannes. 1995. Fresh Water Mollusks of the Upper
Klamath Lake Drainage, Oregon. 1994 yearly report to Oregon Natural
Heritage Program. Deixis Consultants, Seattle, Washington.
Frest, T. J. and E. J. Johannes. 1998. Freshwater Mollusks of the Upper
Klamath Drainage, Oregon. Yearly Report 1998. Deixis Consultants, Seattle,
Washington. Oregon Natural Heritage Program, Portland, Oregon.
Frest, T.J. and E. J. Johannes. 2000. Baseline Mollusk Survey of Southwest
Oregon (Rogue and Umpqua Basins). Deixis Consultants, Seattle, Washington.
Oregon Natural Heritage Program, Portland, Oregon.
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Frest, T.J. and E. J. Johannes. 2005. Grazing effects on springsnails, CascadeSiskiyou National Monument, Oregon, 2004 Report. Deixis Consultants,
Seattle, Washington. 188 pp.
Hannibal, H. 1912. A synopsis of the recent and Tertiary fresh-water Mollusca
of the Californian Province, based upon an ontogenetic classification.
Proceedings of the Malacological Society of London 10: 112-211.
Henderson, J. 1936. The Non-marine Mollusca of Oregon and Washington. The
University of Colorado Studies 17(2): 47-190.
Johnson, P. D., A. E. Bogan, K. M. Brown, N. M. Burkhead, J. R. Cordeiro, J.
T. Garner, P. D. Hartfield, D. A. W. Lepitzki, G. L. Mackie, E. Pip, T. A. Tarpley,
J. S. Tiemann, N. V. Whelan and E. E. Strong. 2013. Conservation Status of
Freshwater Gastropods of Canada and the United States. Fisheries 38: 247282.
Natureserve. 2015. NatureServe Explorer: An online encyclopedia of life [web
application]. Version 7.0. NatureServe, Arlington, VA. U.S.A. Available
http://explorer.natureserve.org. (Accessed: February 2015).
OR/WA BLM. [February 2015]. wpr_geobob_fauna_obs_point.
Pilsbry, H. A. 1925. The family Lancidae distinguished from the Ancylidae. The
Nautilus 38(3): 73-75.
Smith, D. G. 2001. Pennak's Freshwater Invertebrates of the United States:
Porifera to Crustacea, 4th ed. New York: John Wiley & Sons. 638 pp.
Taylor, D. W. 1981. Freshwater Mollusks of California: A Distributional
Checklist. California Fish and Game 67(3): 140-163.
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 ed. American Fisheries Society Special Publication
26, Bethesda, Maryland. 526 pp.
USGS. Nonindigenous Aquatic Species Database. Accessed 3/5/2015.
Available at: http://nas.er.usgs.gov/default.aspx
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ATTACHMENT 2: List of pertinent or knowledgeable contacts
Ed Johannes, Deixis Consultants
Tom Burke, retired
Barry Roth, independent consultant
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ATTACHMENT 3: Map of species’ occurrence in Oregon
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ATTACHMENT 4: Photographs of this species
Photo of Lanx klamathensis c Femorale; Mollusks of Brazil and around the
world. Image licensed under Creative Commons
(http://creativecommons.org/licenses/by-nc/3.0/), which permits one to
“Share — copy and redistribute the material in any medium or format” for noncommercial purposes. Image and licensing information available online:
http://eol.org/data_objects/29466578.
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ATTACHMENT 5: Aquatic Gastropod Survey Protocol, including specifics
for this species:
Taxonomic group:
Aquatic Gastropoda
How:
Please refer to the following documents for detailed mollusk survey
methodology:
1. General collection and monitoring methods for aquatic mollusks (pages 6471):
Frest, T.J. and E.J. Johannes. 1995. Interior Columbia Basin mollusk
species of special concern. Final report: Interior Columbia Basin
Ecosystem Management Project, Walla Walla, WA. Contract #43-0E00-49112. 274 pp. plus appendices.
2. Standard survey methodology that can be used by field personnel to
determine presence/absence of aquatic mollusk species in a given waterbody,
and to document species locations and habitats in a consistent format:
Duncan, N. 2008. Survey Protocol for Aquatic Mollusk Species:
Preliminary Inventory and Presence/Absence Sampling. Version 3.1.
Portland, OR. Interagency Special Status/Sensitive Species Program.
U.S. Department of Interior, Bureau of Land Management,
Oregon/Washington and U.S. Department of Agriculture, Forest Service,
Region 6. 52 pp. [Available at:
http://www.fs.fed.us/r6/sfpnw/issssp/species-index/faunainvertebrates.shtml].
Species-specific survey details, including:
1. Identification features
2. Historic and current distribution
3. Federal Units where species is suspected or documented
4. Areas where surveys are recommended
5. Habitat where surveys should take place
6. Commonly associated mollusk species
7. General survey method and instructions (e.g. time of year)
Lanx klamathensis
The scale lanx has been reported in the Klamath Basin of Oregon and
California and is typically found on cobble or boulder substrate in
groundwater-fed perennial springs, streams, and lakes. Surveys are
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recommended in typical habitat of good quality, with a priority on areas where
land or aquatic management actions may impact this species. Surveys should
focus on revisiting known sites to evaluate current population status, as many
sites have not been surveyed since the 1990s. In particular, estimates of
abundance at sites would improve understanding of these populations.
This species is documented on the Lakeview District BLM in the Klamath Falls
Resource Area and is suspected on the Upper Klamath River ACEC and the
Medford District BLM. This species is also documented on the FremontWinema National Forest. This species is suspected on the Rogue-Siskiyou
National Forest based on Frest and Johannes (1998).
This species can be identified by a large, flattened, thin shell (11-16mm length,
7.5-9.5mm width, and 3-3.5mm height, Hannibal 1912; Henderson 1936).
Shell width and length are both many times greater than height (Hannibal
1912; Pilsbry 1925; Henderson 1936; Frest and Johannes 1995). Lanx alta
(highcap lanx) also occurs in the Klamath Basin and can be distinguished from
L. klamathensis by its greater shell height (2/3 of 15mm shell length average,
approximately 10 mm; Frest and Johannes 2005; Dillon 2006).
Surveys have been conducted for this species in June, August, and October.
Because the species is restricted to perennially wet or flowing habitat, surveys
should be conducted at known perennial sites or in drier months (summer
through fall). Impacts to water quality and quantity will also be more noticeable
in drier months. Surveys conducted in river habitat should avoid periods of
high water or flow, when conditions may be technically difficult or unsafe. Dip
net and hand collection are two common collection methods for this species.
This species commonly is found with a variety of other rare forms, including
Pyrgulopsis archimedis, Pyrgulopsis n. sp. 1, Lyogyrus spp., Fluminicola spp.,
and Vorticifex klamathensis klamathensis (Frest and Johannes 1995). Lanx alta
has also been reported nearby (OSU OSAC: LAK01-014).
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