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 1 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 2 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). 3 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 4 Edited by: Rob Huff FS/BLM Conservation Planning Coordinator January 2010 ATTACHMENT 1: References ATTACHMENT 2: List of pertinent or knowledgeable contacts ATTACHMENT 3: Map of species’ occurrence ATTACHMENT 4: Photographs of this species ATTACHMENT 5: Aquatic Gastropod Survey Protocol, including specifics for this species ATTACHMENT 1: 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