Lithobates onca - (Cope in Yarrow, 1875)
Relict Leopard Frog
Synonym(s): Rana onca Cope, 1875
Taxonomic Status: Accepted
Related ITIS Name(s): Lithobates onca (Cope in Yarrow, 1875) (TSN 775105)
Unique Identifier: ELEMENT_GLOBAL.2.106274
Element Code: AAABH01150
Informal Taxonomy: Animals, Vertebrates - Amphibians - Frogs and Toads
 
Kingdom Phylum Class Order Family Genus
Animalia Craniata Amphibia Anura Ranidae Lithobates
Genus Size: D - Medium to large genus (21+ species)
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Concept Reference
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Concept Reference: Jaeger, J. R., B. R. Riddle, R. D. Jennings, and D. F. Bradford. 2001. Rediscovering RANA ONCA: evidence for phylogenetically distinct leopard frogs from the border region of Nevada, Utah, and Arizona. Copeia 2001:339-354.
Concept Reference Code: A01JAE01NAUS
Name Used in Concept Reference: Rana onca
Taxonomic Comments: Vegas Valley leopard frog, R. fisheri, (now considered extinct) previously was regarded as a subspecies of R. onca. Jennings et al. (1995) conducted morphological comparisons and concluded that R. fisheri and R. onca are distinct species. Jaeger et al. (2001) examined variation in mtDNA and morphology and concluded that certain leopard frog populations in the Virgin River/Black Canyon (Colorado River) region represent a species (R. onca) distinct from the lowland leopard frog (R. yavapaiensis).
Conservation Status
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NatureServe Status

Global Status: G1G2
Global Status Last Reviewed: 29Sep2010
Global Status Last Changed: 29Sep2010
Rounded Global Status: G1 - Critically Imperiled
Reasons: This frog occupies only 10-20 percent of the historical range and currently occurs in 8 natural and 5 translocation sites in Nevada. Primary threats include water diversions and developments, the presence of non-native predators and competitors, loss and fragmentation of habitat, and low numbers of individuals in metapopulations. Currently, no specific water developments or direct habitat losses are known that could result in impacts to the species, and the numbers of individuals and sites occupied by the frog are increasing through captive-rearing and translocation.
Nation: United States
National Status: N1N2 (29Sep2010)

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), Nevada (S1), Utah (SX)

Other Statuses

U.S. Fish & Wildlife Service Lead Region: R8 - California-Nevada
IUCN Red List Category: EN - Endangered

NatureServe Global Conservation Status Factors

Range Extent: 250-1000 square km (about 100-400 square miles)
Range Extent Comments: The known historical distribution includes springs, streams, and wetlands within the Virgin River drainage downstream from the vicinity of Hurricane, Utah; along the Muddy River, Nevada; and along the Colorado River from its confluence with the Virgin River downstream to Black Canyon below Lake Mead, Nevada and Arizona; all historical localities are at or within a few kilometers of these rivers, but this apparent restriction to the proximity of the main rivers may be partially an artifact of historical collecting activities (USFWS 2004). This species also may have occurred at lowland localities along the Colorado River upstream from the confluence with the Virgin River, but no known specimens exist from this area (Relict Leopard Frog Conservation Team 2005).

Relict leopard frogs are currently known to occur in two general areas in Nevada: near the Overton Arm area of Lake Mead, and Black Canyon below Lake Mead. Specimen records date back to 1936 at the Overton Arm area and to 1955 at Black Canyon. These two areas encompass maximum linear extents of only 3.6 and 5.1 kilometers, respectively (USFWS 2009). Relict leopard frog populations may possibly occur in other localized areas (USFWS 2009).

Two leopard frogs have been observed on different occasions in 2000 and 2001 at the fish hatchery at Willow Beach, Arizona, 10 km downstream from Bighorn Sheep Spring in Black Canyon; one of these frogs was collected and confirmed as R. onca based on mitochondrial DNA sequence similarity (C. Fiegel, pers. comm., 2001, cited by USFWS 2009). This individual was likely swept downstream from the occupied sites in Nevada.

Area of Occupancy: 3-500 4-km2 grid cells
Area of Occupancy Comments: Occupied areas in the Overton Arm area of Lake Mead and Black Canyon below Lake Mead encompass maximum linear extents of only 3.6 and 5.1 km, respectively (USFWS 2009).

Number of Occurrences: 1 - 5
Number of Occurrences Comments: The species is extant in only five locations in two general areas (Bradford et al. 2004, USFWS 2009). It occurs in multiple specific sites in each location. As of 2008, 13 sites (8 natural and 5 translocation sites) supported relict leopard frogs (egg masses observed at 10 of 13 sites) (USFWS 2009).

Population Size: 1000 - 2500 individuals
Population Size Comments: An estimate for the total number of frogs at all sites, based on mark-recapture data, visual encounter surveys, and extent of habitat, was approximately 1,100 adults (range 693-1,833) (Bradford et al. 2004)..

Number of Occurrences with Good Viability/Integrity: None (zero)

Overall Threat Impact: Very high - high
Overall Threat Impact Comments: The causes of the decline are not entirely clear, but suggested factors include alteration of aquatic habitat due to agriculture and water development, and the introduction of exotic predators and competitors (Jennings 1988, Jennings and Hayes 1994). The formation of Lake Mead in 1935 and Lake Mojave in 1951 inundated many river miles and adjacent associated wetlands and fragmented some of the remaining populations (USFWS 2009). Connectivity among the extant populations has almost certainly been dramatically reduced as a result of damming the Colorado River (USFWS 2009). The reduction in connectivity is a result of a wider waterbody created when the Colorado River was dammed, thus preventing frogs from moving from one side of the river to the other. Lake Mohave influences the river level such that the canyon floor is never exposed, predatory game fishes are present in the river, and water is continually cool as it emerges from Lake Mead (USFWS 2009). Moreover, wetland habitat has been converted to agriculture or urban development near the Virgin and Muddy Rivers in Utah, Arizona, and Nevada (USFWS 2004). Also, along the Virgin River, the hydrological regime has been substantially changed by upstream impoundments, diversions, and ground water pumping (BIO-WEST, Inc., 2001; USFWS 2009).

Two recent population extinctions occurred concomitantly with encroachment of emergent vegetation into pools; this may have occurred as a result of natural processes in one case, and anthropogenic processes in the other (Bradford et al. 2004).

Exotic species, which are often implicated as serious predators and competitors of native ranid frogs in the western U.S., have become widely distributed along the Virgin, Muddy, and Colorado Rivers. Included among these are the American bullfrog, many species of exotic fishes, and red swamp crayfish (Procambarus clarkii) (Jennings and Hayes 1994). These species potentially prey on all life stages of the relict leopard frog. Bullfrogs also negatively impact native amphibians through competition for prey and coversites. Crayfish and exotic fishes may be important predators on eggs and larvae of relict leopard frogs. [from USFWS 2002]

The relict leopard frog is further threatened by the low numbers of individuals within each population, some of which may not be viable. Amphibians are thought to have a metapopulation structure (i.e., groups of individuals inhabiting a system of habitat patches connected by migration across contiguous habitat). Populations that occur in isolated patches may be extirpated by stochastic events such that recolonization may not occur due to the distance of separation and absence of contiguous habitat. Genetic drift and inbreeding depression may also occur as a result of restricted gene flow associated with small, isolated populations, thus further threatening their persistence. [from USFWS 2002]

Chytridiomycosis, a fungal disease associated with population declines of various amphibian species, although not yet confirmed as a pathogen of relict leopard frogs, must be regarded as a potential threat.

Extirpations

Between 1991 and 1995, habitat change was conspicuous at Corral Springs. The pools that were initially largely open with scattered emergent vegetation became choked with emergent vegetation, primarily native Scirpus spp. By early summer of 1994, most of these pools had virtually no open water. Extirpation of leopard frogs from this site may have been the result of natural processes, because individuals may periodically colonize this site from Rogers Spring during wet periods after the site is scoured by flood waters, and populations may subsequently be extirpated due to shrinkage of aquatic habitat and vegetation encroachment as drier conditions prevail. The demise of the relict leopard frog at Corral Spring may also have been facilitated by the construction of a fence in 1991 to exclude feral burros from most of the site, an action that encouraged overgrowth of emergent vegetation. [from USFWS 2002]

As at Corral Spring, the demise of the population at Littlefield occurred concomitantly with loss of pool habitat due to rapid encroachment of emergent vegetation. Between 1992 and 2001, vegetation cover (primarily Scirpus spp.) had increased dramatically such that no pools of open water remained exposed except for the artificial pond. This rapid encroachment may have resulted from anthropogenic processes. Historically, prior to the establishment of reservoirs in the Virgin River watershed, the emergent vegetation at the Littlefield site would have been scoured periodically by flooding of the Virgin River. Until some years ago, vegetation in part of this area was kept open by light to moderate livestock grazing. Subsequently, with the absence of both flood action and grazing, emergent vegetation grew over virtually all the former open water at the site. Moreover, introduced bullfrogs, which may prey on the relict leopard frog, have become established in wetlands along this portion of the Virgin River (BIO-WEST, Inc., 2001). [from USFWS 2002]

Short-term Trend: Decline of <30% to relatively stable
Short-term Trend Comments: Two of seven populations that were extant in the 1990s have been extirpated (Bradford et al. 2004).

Long-term Trend: Decline of 70-90%
Long-term Trend Comments: USFWS (2009) estimated that the current distribution is approximately 10 to 20 percent of the historical distribution.

Intrinsic Vulnerability: Moderately vulnerable

Other NatureServe Conservation Status Information

Protection Needs: See management summary.

Distribution
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Global Range: (250-1000 square km (about 100-400 square miles)) The known historical distribution includes springs, streams, and wetlands within the Virgin River drainage downstream from the vicinity of Hurricane, Utah; along the Muddy River, Nevada; and along the Colorado River from its confluence with the Virgin River downstream to Black Canyon below Lake Mead, Nevada and Arizona; all historical localities are at or within a few kilometers of these rivers, but this apparent restriction to the proximity of the main rivers may be partially an artifact of historical collecting activities (USFWS 2004). This species also may have occurred at lowland localities along the Colorado River upstream from the confluence with the Virgin River, but no known specimens exist from this area (Relict Leopard Frog Conservation Team 2005).

Relict leopard frogs are currently known to occur in two general areas in Nevada: near the Overton Arm area of Lake Mead, and Black Canyon below Lake Mead. Specimen records date back to 1936 at the Overton Arm area and to 1955 at Black Canyon. These two areas encompass maximum linear extents of only 3.6 and 5.1 kilometers, respectively (USFWS 2009). Relict leopard frog populations may possibly occur in other localized areas (USFWS 2009).

Two leopard frogs have been observed on different occasions in 2000 and 2001 at the fish hatchery at Willow Beach, Arizona, 10 km downstream from Bighorn Sheep Spring in Black Canyon; one of these frogs was collected and confirmed as R. onca based on mitochondrial DNA sequence similarity (C. Fiegel, pers. comm., 2001, cited by USFWS 2009). This individual was likely swept downstream from the occupied sites in Nevada.

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, NV, UTextirpated

Range Map
Note: Range depicted for New World only. The scale of the maps may cause narrow coastal ranges or ranges on small islands not to appear. Not all vagrant or small disjunct occurrences are depicted. For migratory birds, some individuals occur outside of the passage migrant range depicted. For information on how to obtain shapefiles of species ranges see our Species Mapping pages at www.natureserve.org/conservation-tools/data-maps-tools.

Range Map Compilers: IUCN, Conservation International, NatureServe, and collaborators, 2004


U.S. Distribution by County Help
State County Name (FIPS Code)
AZ Mohave (04015)
NV Clark (32003)
UT Washington (49053)*
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
15 Lake Mead (15010005)+, Grand Wash (15010006)+, Upper Virgin (15010008)+*, Fort Pierce Wash (15010009)+*, Lower Virgin (15010010)+*, Muddy (15010012)+*, Havasu-Mohave Lakes (15030101)+
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History
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Basic Description: A leopard frog.
General Description: This is a medium-sized frog (4.4-8.9 centimeters snout-vent length. Generally, it is brown to gray above with greenish brown spots that are often reduced or obscure on the front of the body. The colors underneath are white to yellow with occasional grey or brown mottling. The dorsolateral folds are indistinct and end well before the groin. A light line runs from below the eye, under the tympanum, to behind the angle of the mouth (Stebbins 2003).
Reproduction Comments: Information is incomplete due to inadequate study; eggs have been found in November and February; calling has been heard in February, June, November (Jennings et al. 1995). Individuals reach sexual maturity in 1-2 years, and some likely live 4-5 years or more.
Habitat Type: Freshwater
Non-Migrant: N
Locally Migrant: N
Long Distance Migrant: N
Riverine Habitat(s): CREEK, Pool, SPRING/SPRING BROOK
Lacustrine Habitat(s): Deep water, Shallow water
Palustrine Habitat(s): HERBACEOUS WETLAND, Riparian
Special Habitat Factors: Benthic, Fallen log/debris
Habitat Comments: Historically, this frog probably occupied a variety of habitats including springs, streams, and wetlands characterized by clean, clear water, in both deep and shallow water, and cover such as submerged, emergent, and perimeter vegetation (USFWS 2009). Leopard frogs generally require shallow water with emergent and perimeter vegetation for foraging and basking, and deeper water, root masses, undercut banks, and debris piles for cover and hibernacula (Relict Leopard Frog Conservation Team 2005). Emergent or submergent vegetation provides cover and egg-deposition substrate (Relict Leopard Frog Conservation Team 2005). Adults appear to prefer relatively open shorelines where dense vegetation does not dominate (Bradford et al. 2005). The recently extant populations inhabit spring systems with largely unaltered hydrology and no introduced American bullfrogs or game fishes (Bradford et al. 2004).
Adult Food Habits: Invertivore
Immature Food Habits: Herbivore
Food Comments: Adults probably are mainly invertivorous. Larvae probably eat algae, organic debris, plant tissue, and minute organisms in water.
Adult Phenology: Crepuscular, Nocturnal
Immature Phenology: Crepuscular, Nocturnal
Phenology Comments: These frogs are inactive in cold temperatures. Most activity occurs at night.
Length: 8 centimeters
Economic Attributes Not yet assessed
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Management Summary
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Stewardship Overview: Recent conservation activities included the following (USFWS 2009): Maintaining frog-rearing facilities at the Willow Beach National Fish Hatchery. Planning for a relict leopard frog habitat project at the Willow Beach National Fish Hatchery. Augmenting six existing translocation sites (Goldstrike Canyon; Grapevine Spring, Arizona; Lower Grapevine Spring, Nevada; Pupfish Refuge, Black Canyon, Nevada; Red Rock Spring, Nevada (east of Overton Arm); and Tassi Spring, Arizona). Monitoring all translocated and natural populations. Enhancing habitat at the Pupfish Refuge and Salt Cedar Spring sites in Black Canyon. Working with conservation partners to establish a refugium near the Muddy River. Working with the Nevada Division of State Parks (NDSP) to develop an agreement to establish a refuge at Ash Grove Spring (Spring Mountain Ranch State Park). Finishing a GIS database of natural, transplanted, and potential sites. Beginning the implementation of three Clark County Multiple Species Habitat Conservation Plan (MSHCP) proposals: delineation of distribution, evaluation of relatedness, and assessment of connectivity for relict leopard frog populations; relict leopard frog monitoring and management; evaluation of experimental habitat manipulations on relict leopard frog populations. Investigating new translocation sites in Black Canyon and Gold Butte. Continuing to plan for a refuge site at the Las Vegas Springs Preserve. Investigating the potential for a water pumping station as a relict leopard frog site. Working with the NPS Data Management Team to ensure timely distribution of work products to the Conservation Team. Incorporating relict leopard frog conservation priorities into the Virgin River Habitat Conservation and Recovery Plan. Assessing chytrid fungus pathogen status in relict leopard frogs. Clearing Union Pass Spring and Quail Spring for translocation. Following up on Stuart Ranch and Pakoon Springs as potential translocation sites.

Recommended conservation measures include the following (USFWS 2009): 1. Remove or substantially minimize threats to extant populations and occupied habitats. 2. Enhance existing habitat and/or create new habitats where feasible. 3. Establish additional populations of relict leopard frogs in existing or created habitats. 4. Manage relict leopard frogs and their habitats to ensure persistence in diverse aquatic ecosystems, and facilitate processes that promote self-sustaining populations. 5. Monitor relict leopard frog populations. 6. Investigate the conservation biology of the relict leopard frog, and use the results of such investigations to better meet the goal and objectives.

Monitoring Requirements: Surveys should be done at night, at least twice weekly during expected periods of breeding (fall and late winter) (Jennings et al. 1995).
Management Research Needs: Habitat conditions required for long-term survival need to be determined, as does the importance of bighorn sheep and burros in maintaining favorable habitat (Jennings et al. 1995).
Biological Research Needs: See management summary.
Population/Occurrence Delineation
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Group Name: Ranid Frogs

Use Class: Not applicable
Subtype(s): Breeding Location
Minimum Criteria for an Occurrence: Occurrences are based on evidence of historical presence, or current and likely recurring presence, at a given location. Such evidence minimally includes collection or reliable observation and documentation of one or more individuals (including larvae or eggs) in or near appropriate habitat where the species is presumed to be established and breeding.
Separation Barriers: Busy major highway, especially at night, such that frogs rarely if ever cross successfully; urban development dominated by buildings and pavement; habitat in which site-specific data indicate the frogs virtually never occur.
Separation Distance for Unsuitable Habitat: 1 km
Separation Distance for Suitable Habitat: 5 km
Separation Justification: BARRIERS/UNSUITABLE HABITAT: Rivers may or may not be effective barriers, depending on stream width and flow dynamics; identification of streams as barriers is a subjective determination. Ranid frog species vary in habitat use, but even the most aquatic species may traverse upland habitat when conditions are suitable (Pope and Matthews 2001); natural and seminatural upland habitat generally does not constitute a barrier. Here, unsuitable habitat refers to upland habitat devoid or nearly devoid of wetlands, streams, ponds, or lakes. Bodies of water dominated by predatory fishes may be barriers to some species but suitable habitat for others; in most cases, such waters probably should be regarded as unsuitable habitat.

SUITABLE HABITAT: Suitable habitat includes riparian/riverine corridors, wetlands, and wetland/upland mosaics in which wetland patches are separated by less than 1 km of upland habitat; it also includes any upland habitat regularly used for feeding or wintering (e.g., mesic forest for wood frogs).

MOVEMENTS: Available information indicates that individual ranids occasionally move distances of several km (R. luteiventris: Reaser 1996, cited by Koch et al. 1997; R. blairi: Gillis 1975) but most individuals stay within a few kilometers of their breeding sites (R. aurora draytonii: USFWS, Federal Register, 11 September 2000; R. capito: Franz et al. 1988; R. clamitans: Lamoureux and Madison 1999; R. luteiventris: Turner 1960, Hollenbeck 1974, Bull and Hayes 2001). Similarly, maximum distance between capture points generally is a few kilometers or less (R. aurora: Hayes et al. 2001; USFWS, Federal Register, 11 September 2000; R. catesbeiana: Willis et al. 1956; R. luteiventris: Reaser and Pilliod, in press; Engle 2000; R. muscosa: Pope and Matthews 2001). Dispersal data for juveniles are lacking for most species.

Adult and juvenile R. sylvatica readily traveled in excess of 300 m from their pools of origin (Vasconcelos and Calhoun 2004). Bellis (1965) determined that adult and juvenile R. sylvatica in a peat bog had traveled at least 410 m from the nearest breeding pool. Berven and Grudzien (1990) found that dispersing R. sylvatica juveniles traveled an average of 1,208 m from their natal pools. In the Shenandoah Mountains, data for R. sylvatica indicated that ponds separated by a distance greater than 1,000 m should experience little gene flow (Berven and Grudzien 1991). In contrast, populations in Minnesota were very similar in allelic frequencies, even at distances greater than several kilometers (Squire and Newman 2002). However, sample sizes and number of loci examined were small, and genetic patterns do not necessarily reflect movement distances.

The preponderance of data for ranids indicate that a separation distance of several kilometers may be appropriate for suitable habitat and practical for occurrence delineation, despite occasional movements that are longer and that may allow some genetic interchange between distant populations. The movement data for ranids are here regarded as consistent enough to allow the same separation distance to be used for different species; much of the apparent variation in movements doubtless reflects differences in study methods and in the ability to detect long-distance movements.

Date: 01Apr2005
Author: Hammerson, G.
Population/Occurrence Viability
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U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed
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Authors/Contributors
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NatureServe Conservation Status Factors Edition Date: 04Apr2011
NatureServe Conservation Status Factors Author: Hammerson, G.
Element Ecology & Life History Edition Date: 29Sep2010
Element Ecology & Life History Author(s): Hammerson, G.

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

References
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  • BIO-WEST, Inc. 2001. An ecological evaluation of the lower Virgin River riparian corridor: final report. Submitted to the Southern Nevada Water Authority, Las Vegas, Nevada.

  • Behler, J. L., and F. W. King. 1979. The Audubon Society field guide to North American reptiles and amphibians. Alfred A. Knopf, New York. 719 pp.

  • Behler, J. L., and F. W. King. 1979. The Audubon Society field guide to North American reptiles and amphibians. Knopf, New York. 743 pp.

  • Blackburn, L., P. Nanjappa, and M. J. Lannoo. 2001. An Atlas of the Distribution of U.S. Amphibians. Copyright, Ball State University, Muncie, Indiana, USA.

  • Bradford, D. F., J. R. Jaeger, and R. D. Jennings. 2004. Population status and distribution of a decimated amphibian, the relict leopard frog (Rana onca). Southwestern Naturalist 49:218-228.

  • Bradford, D. F., J. R. Jaeger, and R. D. Jennings. 2005. Relict leopard frog (Rana onca). Pages 567-568 in M. Lannoo, editor. Amphibian declines: the conservation status of United States species. University of California Press, Berkeley.

  • Collins, J. T. 1990. Standard common and current scientific names for North American amphibians and reptiles (3rd ed.). Soc. Study Amphibians Reptiles, Herpetol. Circular No. 19, iii+ 41 pp.

  • Cope, E. D. 1875. Rana onca Cope, sp. nov., pp 528-529 in H. C. Yarrow, Reort upon the collections of batrachians and reptiles made in ... Vevada ... and Arizona during 1871 ... 1874, chapter IV, pp 509-584, in Report upon ... surveys west of the one-hundredth meridian, in charge of ... Geo. M. Wheeler .... Vol. V--Zoology. Govt. Printing Office, Washington.

  • Frost, D. R. 2002. Amphibian Species of the World: an online reference. V2.21 (15 July 2002). Electronic database available at http://research.amnh.org/herpetology/amphibia/index.html.

  • Frost, D. R. 2010. Amphibian Species of the World: an Online Reference. Version 5.4 (8 April 2010). Electronic Database accessible at http://research.amnh.org/herpetology/amphibia/index.php. American Museum of Natural History, New York, USA.

  • Frost, D.R., et al., 2006. The Amphibian Tree of Life. Bulletin of the American Museum of Natural History no. 297: 1-370. [15 Mar 2006]

  • Jaeger, J. R., B. R. Riddle, R. D. Jennings, and D. F. Bradford. 2001. Rediscovering RANA ONCA: evidence for phylogenetically distinct leopard frogs from the border region of Nevada, Utah, and Arizona. Copeia 2001:339-354.

  • Jaeger, J. R., B. R. Riddle, R. D. Jennings, and D. F. Bradford. 2001. Rediscovering Rana onca: evidence for phylogenetically distinct leopard frogs from the border region of Nevada, Utah, and Arizona. Copeia 2001: 339-354.

  • Jennings, M. R. 1988. Rana onca. Catalogue Amer. Amphibians Reptiles 417: 1-2.

  • Jennings, M. R., and M. P. Hayes. 1994. Decline of native ranid frogs in the desert southwest. Pages 183-211 in P. R. Brown and J. W. Wright (editors). Herpetology of the North American Deserts, Southwestern Herpetologists society, Special Publication Number 5.

  • Jennings, M.R. 1988. Rana onca Cope, relict leopard frog. Catalogue of American Amphibians and Reptiles. 417:1-2.

  • Jennings, R. D., B. R. Riddle, and D. Bradford. 1995. Rediscovery of Rana onca, the relict leopard frog, in southern Nevada with comments on the systematic relationships of some leopard frogs (Rana pipiens complex) and the status of populations along the Virgin River. Report prepared for Arizona Game and Fish Dept., U.S. Bureau of Land Management, Las Vegas Valley Water District, U.S. National Park Service, and Southwest Parks and Monuments Association.73 pp.

  • Jennings, R. D., B. R. Riddle, and D. Bradford. 1995. Rediscovery of Rana onca, the relict leopard frog, in southern Nevada with comments on the systematic relationships of some southwestern leopard frogs (Rana pipiens complex) and the status of populations along the Virgin River. Prepared for Reno Office, USFWS. 73 pp.

  • Platz, J. E. 1984. Status report for Rana onca. Prepared for Office of Endangered Species, U.S. Fish and Wildlife Service, Albuquerque, NM. 22 pp.

  • Platz, J.E. 1984. Status report for Rana onca cope. Report to Fish and Wildlife Service, Albuquerque.

  • Relict Leopard Frog Conservation Team. 2005. Conservation agreement and rangewide conservation assessment and strategy for the relict leopard frog (Rana onca). July 2005. 164 pp.

  • Stebbins, R. C. 1985. A field guide to western reptiles and amphibians. Houghton Mifflin Co., Boston. xiv + 336 pp.

  • Stebbins, R. C. 1985a. A field guide to western reptiles and amphibians. Second edition. Houghton Mifflin Company, Boston, Massachusetts. xiv + 336 pp.

  • Stebbins, R. C. 2003. A field guide to western reptiles and amphibians. Third edition. Houghton Mifflin Company, Boston.

  • Tanner, V. M. 1929. A distributional list of the amphibians and reptiles of Utah, no. 3. Copeia (171): 46-52.

  • Tanner, V. M. 1931. A synoptical study of Utah Amphibia. Proc. Utah Acad. Sci. 8: 159-198.

  • U. S. Fish and Wildlife Service (USFWS). 2016. Endangered and Threatened Wildlife and Plants; 12-Month Findings on Petitions To List 10 Species as Endangered or Threatened Species. Federal Register. 81(194):69425-69442.

  • U.S. Fish and Wildlife Service (USFWS). 2002. Candidate and listing priority assignment form: relict leopard frog.

  • U.S. Fish and Wildlife Service (USFWS). 2004. Species assessment and listing priority assignment form. Rana onca (relect leopard frog). 14 pp.

  • U.S. Fish and Wildlife Service (USFWS). 2009. Rana onca. Species assessment and listing priority assingment form.

  • Wright, A. H., and A. A. Wright. 1949. Handbook of frogs and toads of the United States and Canada. 3rd ed. Comstock Publ. Assoc., Ithaca, N. Y. xii + 640 pp.

  • ZHI-YONG YUAN, WEI-WEI ZHOU, XIN CHEN, NIKOLAY A. POYARKOV, JR., HONG-MAN CHEN, NIAN-HONG JANG-LIAW, WEN-HAO CHOU, NICHOLAS J. MATZKE, KOJI IIZUKA, MI-SOOK MIN, SERGIUS L. KUZMIN, YA-PING ZHANG, DAVID C. CANNATELLA, DAVID M. HILLIS, AND JING CHE. 2016. Spatiotemporal Diversification of the True Frogs (Genus Rana): A Historical Framework for a Widely Studied Group of Model Organisms.  Systematic Biology 65(5):824-842.

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"Data provided by NatureServe in collaboration with Robert Ridgely, James Zook, The Nature Conservancy - Migratory Bird Program, Conservation International - CABS, World Wildlife Fund - US, and Environment Canada - WILDSPACE."

Citation for Mammal Range Maps of North America:
Patterson, B.D., G. Ceballos, W. Sechrest, M.F. Tognelli, T. Brooks, L. Luna, P. Ortega, I. Salazar, and B.E. Young. 2003. Digital Distribution Maps of the Mammals of the Western Hemisphere, version 1.0. NatureServe, Arlington, Virginia, USA.

Acknowledgement Statement for Mammal Range Maps of North America:
"Data provided by NatureServe in collaboration with Bruce Patterson, Wes Sechrest, Marcelo Tognelli, Gerardo Ceballos, The Nature Conservancy-Migratory Bird Program, Conservation International-CABS, World Wildlife Fund-US, and Environment Canada-WILDSPACE."

Citation for Amphibian Range Maps of the Western Hemisphere:
IUCN, Conservation International, and NatureServe. 2004. Global Amphibian Assessment. IUCN, Conservation International, and NatureServe, Washington, DC and Arlington, Virginia, USA.

Acknowledgement Statement for Amphibian Range Maps of the Western Hemisphere:
"Data developed as part of the Global Amphibian Assessment and provided by IUCN-World Conservation Union, Conservation International and NatureServe."

NOTE: Full metadata for the Bird Range Maps of North America is available at:
http://www.natureserve.org/library/birdDistributionmapsmetadatav1.pdf.

Full metadata for the Mammal Range Maps of North America is available at:
http://www.natureserve.org/library/mammalsDistributionmetadatav1.pdf.

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