Oxyloma haydeni kanabensis - Pilsbry, 1948
Kanab Ambersnail
Synonym(s): Oxyloma kanabense Pilsbry, 1948
Taxonomic Status: Not accepted
Related ITIS Name(s): Oxyloma haydeni kanabensis (TSN 198382) ;Oxyloma kanabense Pilsbry, 1948 (TSN 76925)
Unique Identifier: ELEMENT_GLOBAL.2.116392
Element Code: IMGAS67151
Informal Taxonomy: Animals, Invertebrates - Mollusks - Terrestrial Snails
Kingdom Phylum Class Order Family Genus
Animalia Mollusca Gastropoda Stylommatophora Succineidae Oxyloma
Genus Size: C - Small genus (6-20 species)
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Concept Reference
Concept Reference: Pilsbry, H.A. 1948. Land Mollusca of North America (north of Mexico). Monograph of the Academy of Natural Sciences of Philadelphia, 2(2): 521-1113.
Concept Reference Code: A48PIL01EHUS
Name Used in Concept Reference: Oxyloma haydeni kanabensis
Taxonomic Comments: Note there is a great deal of confusion as to whether populations of this snail represent a subspecies of Oxyloma haydeni (= Oxyloma haydeni kanabensis), or a separate species, Oxyloma kanabense. This taxon may be a subspecies of Oxyloma haydeni but the American Fisheries Society Checklists (Turgeon et al., 1988; 1998) and several authors have suggested that this subspecies deserves species status (Clarke, 1991; Miller, 1997; Spamer and Bogan, 1993; and Oliver and Bosworth, 1999). Genetic analysis of Oxyloma haydeni kanabensis and Oxyloma haydeni haydeni reveals that two populations of these species from Three Lakes (Utah) and Indian Gardens (AZ), respectively, are more closely related to each other than two separate protected populations of Oxyloma haydeni kanabensis from Arizona (Miller et al., 2000). As such, the anatomical characters used to separate these two species are misleading. Revision of North American Oxyloma may be required to address the endangered status of ambersnails in the southwestern United States.
Conservation Status

NatureServe Status

Global Status: G3T1Q
Global Status Last Reviewed: 05Oct2005
Global Status Last Changed: 06Oct1997
Rounded Global Status: T1 - Critically Imperiled
Reasons: Only three known populations exist. The largest population is threatened by development, and is vulnerable due to limited habitat extent.
Nation: United States
National Status: N1 (24Oct2000)

U.S. & Canada State/Province Status
Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
United States Arizona (S1)

Other Statuses

U.S. Endangered Species Act (USESA): LE: Listed endangered (17Apr1992)
U.S. Fish & Wildlife Service Lead Region: R6 - Rocky Mountain
IUCN Red List Category: CR - Critically endangered

NatureServe Global Conservation Status Factors

Range Extent: <100 square km (less than about 40 square miles)
Range Extent Comments: It occurs in southwestern Utah (Kane Co.) (Pilsbry, 1948) and northwestern Arizona (Grand Canyon National Park) at only two sites remaining.

Number of Occurrences: 1 - 5
Number of Occurrences Comments: Originally described from specimens collected in 1909 at "The Greens," Kanab Creek drainage, 6 miles above Kanab (Kane Co., Utah). Known today from two populations, one (a second was extirpated) on private land near Kanab, Utah around several spring fed ponds named Three Lakes (10 km north/northwest of Kanab in Kane Co., Utah; second extirpated population in Kanab Creek Canyon 10 km north of Kanab, Kane Co., Utah; both 2.1 km apart near the Arizona border) (USFWS, 1995), and one at Vaseys Paradise 51 km downstream from Leas Ferry along the Colorado River, in Grand Canyon National Park, Coconino Co., Arizona (this population 92 km southeast of the Utah populations), in an herbaceous wetland on plants (Stevens et al., 1997). The additional, small population was discovered in 1991 in the Grand Canyon, Arizona (USFWS, 1995).

Population Size: 100,000 - 1,000,000 individuals
Population Size Comments: The largest population (Vaseys Paradise) was estimated to contain 100,000 individuals in June 1990. All three known populations very localized and limited in extent. The Vaseys Paradise population was estimated to increase through the 1995 growing season from 18,500 snails in March to 104,000 snails in September in the upper zone. After completion of Glen Canyon Dam, lower zone population changed from 600 to 17,400 snails (March to September) due to growth of plants after the dam was constructed; however habitat loss was anticipated during high flow releases in subsequent years following completion of the dam (Stevens et al., 1997).

Overall Threat Impact: Very high - high
Overall Threat Impact Comments: Threatened by water diversion, livestock grazing, and land development in Utah; by pedestrian traffic in its habitat in Arizona. Smaller populations may be susceptible to extirpation through stochastic forces. A population has been lost due to wetlands destruction, and to a lesser extent, livestock trampling. In 1994, a significant portion of this population was buried by silt deposited by runoff from a series of strong thunderstorms. The habitat of the smaller Utah population (Kanab Creek Canyon) has been dewatered within the past thirty years and is likely extirpated (USFWS, 1995; Stevens et al., 1997). Realized and potential threats stem primarily from loss and/or adverse modification of its wetland habitat. Some individuals and associated habitat may be lost due to high flows and flood releases from Glen Canyon Dam. The Arizona population is vulnerable to uncontrolled floods and controlled high flows of the Colorado River between Glen Canyon Dam and Vasey's Paradise. In addition, the species habitat receives recreational visitation from river runners because of the fresh drinking water available at the site. However, most river runners do not disturb occupied snail habitat. Flash flooding from the Vasey's Paradise spring-head or runoff from the canyon walls in the Grand Canyon in Arizona and in the Three Lakes Canyon drainage in Utah has caused and continues to have the potential to cause the loss of significant portions of the species known populations and has altered the species habitat through siltation and scouring. The demographic stability of the various populations is not known. The smaller Utah population, located in Kanab Creek Canyon, may not be at population levels large enough to ensure the population's long-term survival, may be extirpated. Livestock grazing may be a threat to the survival of the species. The effect of natural factors, such as disease, parasitism, predation, and grazing of its habitat by native species, on the viability of the species population is not known (USFWS, 1995).

Short-term Trend: Decline of 30-50%
Short-term Trend Comments: Recent field work has documented rapid decline of the smaller of the two Utah populations. Two populations existed in the Kanab, Utah, area but one has been extirpated due to habitat destruction (wetlands destruction and to a lesser extent, livestock trampling) while the other is on private property in Utah that is undergoing commercial development (Stevens et al., 1997; USFWS, 1995). The Arizona population is small but may be more stable than either of the known Utah populations and occurs in an herbaceous wetland in Grand Canyon National Park (Stevens et al., 1997); but is potentially declining due to water release practices at Glen Canyon Dam.

Intrinsic Vulnerability: Highly vulnerable
Intrinsic Vulnerability Comments: Individuals are relatively immobile, permanently and absolutely associated with their wetland habitat about desert springs and seeps.

Other NatureServe Conservation Status Information

Protection Needs: It was federally listed as Endangered in 1992 and the Fish and Wildlife Service is now initiating recovery efforts. Landowner of largest population is uncooperative.

Global Range: (<100 square km (less than about 40 square miles)) It occurs in southwestern Utah (Kane Co.) (Pilsbry, 1948) and northwestern Arizona (Grand Canyon National Park) at only two sites remaining.

U.S. States and Canadian Provinces

Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
Color legend for Distribution Map
Endemism: endemic to a single nation

U.S. & Canada State/Province Distribution
United States AZ

Range Map
No map available.

U.S. Distribution by County Help
State County Name (FIPS Code)
AZ Coconino (04005)
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
15 Lower Colorado-Marble Canyon (15010001)+, Grand Canyon (15010002)+
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History
Basic Description: Terrestrial snail
General Description: Fragile shelled ambersnail with large aperture-to-shell length ratio, ovate with decreasing whorls coming to a point. Spire is more slender and drawn out than OXYLOMA HAYDENI HAYDENI and has a shorter aperture (Sorensen and Kubly, 1997; Sorensen and Nelson, 2002). Recent genetic analyses have contradicted some of these findings, leaving taxonomic characters based on morphology in an uncertain state (Miller et al., 2000; Sorensen and Nelson, 2002).
Diagnostic Characteristics: see GENDESC
Habitat Type: Terrestrial
Non-Migrant: N
Locally Migrant: N
Long Distance Migrant: N
Habitat Comments: It occurs in prings and seeps at base of sandstone or limestone cliffs. In Utah, it is on private land near Kanab, Utah around several spring fed ponds named Three Lakes. In Arizona, it is associated with perennially wet surface soil or shallow standing water. It occurs primarily on native Mimulus cardinalis (crimson monkey flower) and non-native Nasturtium officinale (water-cress), and occasionally Carex aquatilis and Polygonum amphibium, growing on moist to saturated substrata wetted by the Vaseys Paradise spring overflow (Stevens et al., 1997).
Economic Attributes Not yet assessed
Management Summary Not yet assessed
Population/Occurrence Delineation
Group Name: Terrestrial Snails

Use Class: Not applicable
Minimum Criteria for an Occurrence: Occurrences are based on some evidence of historical or current presence of single or multiple specimens, including live specimens or recently dead shells (i.e., soft tissue still attached without signs of external weathering or staining), at a given location with potentially recurring existence. Weathered shells constitute a historic occurrence. Evidence is derived from reliable published observation or collection data; unpublished, though documented (i.e. government or agency reports, web sites, etc.) observation or collection data; or museum specimen information.
Separation Barriers: Barriers include barriers to dispersal such as the presence of permanent water bodies greater than 30 m in width, permanently frozen areas (e.g. mountaintop glaciers) which generally lack land snails (Frest and Johannes, 1995), or dry, xeric areas with less than six inches precipitation annually, as moisture is required for respiration and often hatching of eggs. For the various slugs and slug-like species (families Arionidae, Philomycidae, Limacidae, Milacidae, Testacellidae, Veronicellidae), absence of suitable moisture, except for the most ubiquitous of species such as Deroceras reticulatum (Müller, 1774), can serve as a barrier to movement (Frest and Johannes, 1995). Members of these groups tend to have greater difficulty crossing areas of little moisture than other pulmonates. For tree snails (family Bulimulidae [= Orthalicidae]), lack of appropriate arboreal habitat (e.g. distance of greater than 500 m) also serves as a separation barrier.
Separation Distance for Unsuitable Habitat: 1 km
Separation Distance for Suitable Habitat: 1 km
Alternate Separation Procedure: None
Separation Justification: Burch and Pearce (1990) suggest refuges may be the most important factor limiting terrestrial snail abundance, although the greatest richness of species among carbonate cliff habitats (one of the most diverse in North America) is associated with calcareous, as opposed to acidic, substrates (Nekola, 1999; Nekola and Smith, 1999). The panmictic unit (a local population in which matings are random) is small relative to those of other animal groups because terrestrial snails tend to be more sedentary. Baker (1958) claimed, "long-distance dispersal of terrestrial gastropods is undoubtedly passive" although short distance dispersal is active involving slow, short distance migration under favorable conditions. Long-distance passive migration is not considered when assigning separation distances, as otherwise separation distances for many animals and plants would be made impracticably large. Passive migration of snails on terrestrial mammals, birds, or insects may occur over longer distances may occur across barriers. Passive migration also may occur by wind or by rafting on floating objects (Vagvolgyi, 1975). A third form of passive migration may occur through human activity such as transport as food, with consumed goods, or for biological control of other organisms.

Terrestrial gastropods do not move much usually only to find food or reproduce. Olfaction is the primary sensory behavior utilized to find and move toward a food item (on the scale of cm to m) although Atkinson (2003) found that Anguispira alternata was capable of switching foraging behavior when snails encountered a physical barrier to movement. Fisher et al (1980) reported maximum movement rate of Rumina decollata (Linnaeus, 1758), an introduced pest species in California spreading relatively rapidly (for a snail), to be 20 m in three months (= 6.67 m/month) in an irrigated orchard. Tupen and Roth (2001) reported the movement rate for the same species in an un-irrigated native scrub on San Nicolas Island to be 0.4 km in 12 years (= 33.33 m/month). South (1965) found in dispersal studies of the slug, Deroceras reticulatum, that slugs traveled a mean distance of 1.13 m in seven days indicating this species disperses little throughout its life. Giokas and Mylonas (2004) found mean dispersal and minimal movement distances were very small (16.2 and 5.4 m, respectively) for Albinaria coerulea, with few individuals dispersing longer distances. Even the most extreme dispersal distances, such as 500 m for the giant African land snail Achatina fulica (Tomiyama and Nakane, 1993), do not approach the scale of km. Viable land snail populations generally occupy small areas. Frest and Johannes (1995) report the largest Oreohelix colony they observed was one mile (1.67 km) long and 0.25 miles (0.41 km) wide while the smallest was six feet (183 cm) long and two feet (61 cm) wide.

As a whole, pulmonates (previously Subclass Pulmonata) are better dispersers than prosobranchs (previously Subclass Prosobranchia) possibly due to their hermaphroditic reproduction increasing the chance of new colonization (Pilsbry, 1948). When compared with prosobranch families, pulmonates generally reproduce at smaller sizes and sooner, produce greater numbers of eggs/young, have larger clutch sizes, greater growth rates, and shorter life cycles (Brown, 1991). Further, prosobranchs' requirement of constant moisture for oxygen exchange limits their ability to colonize drier habitats. Suitable habitat for pulmonate groups tends to be more varied and less restrictive than for prosobranch groups. All of these factors contribute to pulmonates greater dispersal capability over prosobranchs, as evidenced by the wider and more varied distribution of pulmonates over prosobranchs. Despite this, separation distance for both groups is set at the minimum one km as most movements are well within this suggested minimum separation distance.

Date: 26May2004
Author: Cordeiro, J.
Population/Occurrence Viability
U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed
NatureServe Conservation Status Factors Edition Date: 02Mar2009
NatureServe Conservation Status Factors Author: Cordeiro, J. (2009); Doug Stone (1994)
Element Ecology & Life History Edition Date: 02Mar2009
Element Ecology & Life History Author(s): Cordeiro, J.

Zoological data developed by NatureServe and its network of natural heritage programs (see Local Programs) and other contributors and cooperators (see Sources).

  • Clarke, A. H. 1991. Final Report: Status Survey of selected land and freshwater gastropods in Utah. Ecosearch, Inc., Portland, Texas. Report submitted to U.S. Fish and Wildlife Service. Contract no. 14-16-0006-89-021.

  • Miller, M.P., J. Busch and P. Keim. 1997. Genetic diversity, population structure, and relationships of the Kanab amber snail (Oxyloma haydeni kanabensis) and Hayden's amber snail (Oxyloma haydeni haydeni) in the southwest USA. Contract technical report to Arizona Game and Fish Department. Northern Arizona University, Department of Biological Sciences, Flagstaff.

  • Miller, M.P., L.E. Stevens, J.D. Busch, J.A. Sorensen, and P. Keim. 2000. Amplified fragment length polymorphism and mitochondrial sequence data detect genetic differentiation and relationships in endangered southwestern U.S.A. ambersnails (Oxyloma spp.). Canadian Journal of Zoology, 78: 1845-1854.

  • 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.

  • Pilsbry, H.A. 1948. Land Mollusca of North America (north of Mexico). Monograph of the Academy of Natural Sciences of Philadelphia, 2(2): 521-1113.

  • Sorensen, J.A. and C.B. Nelson. 2002. Interim conservation plan for Oxyloma (haydeni) kanabensis complex and related ambersnails in Arizona and Utah. Technical Report 192 to the Nongame and Endangered Wildlife Program, Arizona Game and Fish Department, Phoenix, Arizona. 43 pp.

  • Sorensen, J.A. and D.M. Kubly. 2002. Investigations of teh endangered kanab ambersnail: monitoring, genetic studies, and habitat evaluation in Grand Canyon and northern Arizona. Technical Report 122 to the Nongame and Endangered Wildlife Porgram, Arizona Game and Fish Department, Phoenix, Arizona. 102 pp.

  • Spamer, E.E., and A.E. Bogan. 1993. Mollusca of the Grand Canyon and vicinity, Arizona; new and revised data on diversity and distributions, with notes on Pleistocene-Holocene mollusks of the Grand Canyon. Proceedings of the Academy of Natural Sciences of Philadelphia 144:21-68.

  • Stevens, L.E., F.R. Protiva, D.M. Kubly, V.J. Meretsky, and J. Petterson. 1997. The ecology of Kanab ambersnail (Succineidae: Oxyloma haydeni kanabensis Pilsbry, 1948) at Vaseys Paradise, Grand Canyon, Arizona: 1995 final report. Report to The Grand Canyon Monitoring and Research Center, Flagstaff, Arizona. 15 July 1997. 34 pp.

  • 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). 1994. Draft recovery plan for the Kanab ambersnail (Oxyloma haydeni kanabensis). Prepared for Region 2 (Albuquerque, NM) and Region 6 (Denver, CO) offices by J.L. England, USFWS, Salt Lake City, UT. 26 pp.

  • U.S. Fish and Wildlife Service (USFWS). 1995. Kanab ambersnail (Oxyloma haydeni kanabensis) recovery plan. U.S. Fish and Wildlife Service, Denver, Colorado. 21 pp.

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